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Søegaard SH, Rostgaard K, Kamper-Jørgensen M, Schmiegelow K, Hjalgrim H. Childcare attendance and risk of childhood acute lymphoblastic leukaemia: A register study based on the Danish childcare database. Int J Cancer 2023; 152:1817-1826. [PMID: 36545888 DOI: 10.1002/ijc.34413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/17/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
Childhood acute lymphoblastic leukaemia (ALL) is suggested to result from a dysregulated immune response to infections in children with a preleukaemic state. Childcare in early life supposedly may protect against childhood ALL by facilitating sufficient exposure to infections to stimulate and ensure normal maturation of the immune system. We assessed the association between childcare attendance before age 2 years and risk of childhood ALL in a register-based cohort study, including all children aged 2 to 14 years born in Denmark during 1991 to 2014 with available childcare information recorded in the Danish Childcare Database (n = 1 116 185). Cox regression was used to estimate hazard ratios (HRs) comparing children enrolled in childcare and children not enrolled before age 2 years. Further, we assessed the association according to age at enrolment, type of childcare facility and specific ALL subtypes. During 10 460 811 person-years of follow-up, 460 children developed ALL at ages 2 to 14 years. Of these, 57 (12.4%) never attended childcare before age 2 years compared with 10.6% in the total cohort. Compared with homecare, childcare attendance before age 2 years was associated with a statistically non-significantly, marginally decreased risk of childhood ALL with adjusted HR = 0.87 (95% confidence interval [CI]: 0.65-1.16). Risk estimates did neither vary statistically significantly by age at enrolment nor by type of childcare facility and also not between childhood ALL subtypes, including frequently prenatally initiated ALL subtypes. Results from this large, nationwide register-based study provided no evidence that childcare attendance in the first years of life protects against childhood ALL.
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Affiliation(s)
- Signe Holst Søegaard
- Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen, Denmark.,Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - Klaus Rostgaard
- Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen, Denmark.,Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | | | - Kjeld Schmiegelow
- Department of Paediatrics and Adolescent Medicine, University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Hjalgrim
- Danish Cancer Society Research Centre, Danish Cancer Society, Copenhagen, Denmark.,Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Medicine, University of Copenhagen, Copenhagen, Denmark.,Department of Haematology, University Hospital Rigshospitalet, Copenhagen, Denmark
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2
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Cardesa-Salzmann TM, Simon A, Graf N. Antibiotics in early life and childhood pre-B-ALL. Reasons to analyze a possible new piece in the puzzle. Discov Oncol 2022; 13:5. [PMID: 35201533 PMCID: PMC8777491 DOI: 10.1007/s12672-022-00465-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/23/2021] [Indexed: 11/29/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer with precursor B-cell ALL (pB-ALL) accounting for ~ 85% of the cases. Childhood pB-ALL development is influenced by genetic susceptibility and host immune responses. The role of the intestinal microbiome in leukemogenesis is gaining increasing attention since Vicente-Dueñas' seminal work demonstrated that the gut microbiome is distinct in mice genetically predisposed to ALL and that the alteration of this microbiome by antibiotics is able to trigger pB-ALL in Pax5 heterozygous mice in the absence of infectious stimuli. In this review we provide an overview on novel insights on the role of the microbiome in normal and preleukemic hematopoiesis, inflammation, the effect of dysbiosis on hematopoietic stem cells and the emerging importance of the innate immune responses in the conversion from preleukemic to leukemic state in childhood ALL. Since antibiotics, which represent one of the most widely used medical interventions, alter the gut microbial composition and can cause a state of dysbiosis, this raises exciting epidemiological questions regarding the implications for antibiotic use in early life, especially in infants with a a preleukemic "first hit". Sheading light through a rigorous study on this piece of the puzzle may have broad implications for clinical practice.
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Affiliation(s)
- T. M. Cardesa-Salzmann
- Department of Pediatric Hematology and Oncology, Universitätsklinikum des Saarlandes, Homburg, Saarland Germany
| | - A. Simon
- Department of Pediatric Hematology and Oncology, Universitätsklinikum des Saarlandes, Homburg, Saarland Germany
| | - N. Graf
- Department of Pediatric Hematology and Oncology, Universitätsklinikum des Saarlandes, Homburg, Saarland Germany
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3
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Cobaleda C, Vicente-Dueñas C, Sanchez-Garcia I. Infectious triggers and novel therapeutic opportunities in childhood B cell leukaemia. Nat Rev Immunol 2021; 21:570-581. [PMID: 33558682 DOI: 10.1038/s41577-021-00505-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2021] [Indexed: 01/30/2023]
Abstract
B cell acute lymphoblastic leukaemia (B-ALL) is the most common form of childhood cancer. Although treatment has advanced remarkably in the past 50 years, it still fails in ~20% of patients. Recent studies revealed that more than 5% of healthy newborns carry preleukaemic clones that originate in utero, but only a small percentage of these carriers will progress to overt B-ALL. The drivers of progression are unclear, but B-ALL incidence seems to be increasing in parallel with the adoption of modern lifestyles. Emerging evidence shows that a major driver for the conversion from the preleukaemic state to the B-ALL state is exposure to immune stressors, such as infection. Here, we discuss our current understanding of the environmental triggers and genetic predispositions that may lead to B-ALL, highlighting lessons from epidemiology, the clinic and animal models, and identifying priority areas for future research.
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Affiliation(s)
- Cesar Cobaleda
- Immune System Development and Function Unit, Centro de Biología Molecular Severo Ochoa, CSIC and Universidad Autónoma de Madrid, Madrid, Spain.
| | | | - Isidro Sanchez-Garcia
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca, Spain. .,Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, CSIC and Universidad de Salamanca, Salamanca, Spain.
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4
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Hauer J, Fischer U, Borkhardt A. Towards prevention of childhood ALL by early-life immune training. Blood 2021:blood. [PMID: 34010407 DOI: 10.1182/blood.2020009895] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/21/2021] [Indexed: 11/21/2022] Open
Abstract
B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is the most common form of childhood cancer. Chemotherapy is associated with life-long health sequelae and fails in ∼20% of cases. Thus, prevention of leukemia would be preferable to treatment. Childhood leukemia frequently starts before birth, during fetal hematopoiesis. A first genetic hit (eg, the ETV6-RUNX1 gene fusion) leads to the expansion of preleukemic B-cell clones, which are detectable in healthy newborn cord blood (up to 5%). These preleukemic clones give rise to clinically overt leukemia in only ∼0.2% of carriers. Experimental evidence suggests that a major driver of conversion from the preleukemic to the leukemic state is exposure to immune challenges. Novel insights have shed light on immune host responses and how they shape the complex interplay between (1) inherited or acquired genetic predispositions, (2) exposure to infection, and (3) abnormal cytokine release from immunologically untrained cells. Here, we integrate the recently emerging concept of “trained immunity” into existing models of childhood BCP-ALL and suggest future avenues toward leukemia prevention.
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5
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Tebbi CK, Badiga A, Sahakian E, Arora AI, Nair S, Powers JJ, Achille AN, Jaglal MV, Patel S, Migone F. Plasma of Acute Lymphoblastic Leukemia Patients React to the Culture of a Mycovirus Containing Aspergillus flavus. J Pediatr Hematol Oncol 2020; 42:350-8. [PMID: 32576782 DOI: 10.1097/MPH.0000000000001845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Acute lymphoblastic leukemia (ALL) is the most common cancer in children and is also seen in adults. Currently, no plasma-based test for the detection of ALL is available. We have cultured the home of a patient with ALL and isolated a mycovirus containing Aspergillus flavus. This culture was subjected to electron microscopy, purification, and mass spectrometry. Using enzyme-linked immunosorbent assay technique, plasma of patients with ALL and long-term survivors of this disease were tested for antibodies, utilizing supernatant of the culture of this organism. The results were compared with 3 groups of controls, including healthy individuals, patients with sickle cell disease, and solid tumors. Using electron microscopy, the isolated A. flavus contained mycovirus particles. In chemical analysis, this organism did not produce any aflatoxin. Using an enzyme-linked immunosorbent assay technique, the supernatant of the culture of the mycovirus containing A. flavus could differentiate ALL patients from each group of controls (P<0.001). These studies provide a new technique for the detection of ALL and may add information for future research regarding leukemogenesis.
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6
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Abstract
In this Review, I present evidence supporting a multifactorial causation of childhood acute lymphoblastic leukaemia (ALL), a major subtype of paediatric cancer. ALL evolves in two discrete steps. First, in utero initiation by fusion gene formation or hyperdiploidy generates a covert, pre-leukaemic clone. Second, in a small fraction of these cases, the postnatal acquisition of secondary genetic changes (primarily V(D)J recombination-activating protein (RAG) and activation-induced cytidine deaminase (AID)-driven copy number alterations in the case of ETS translocation variant 6 (ETV6)-runt-related transcription factor 1 (RUNX1)+ ALL) drives conversion to overt leukaemia. Epidemiological and modelling studies endorse a dual role for common infections. Microbial exposures earlier in life are protective but, in their absence, later infections trigger the critical secondary mutations. Risk is further modified by inherited genetics, chance and, probably, diet. Childhood ALL can be viewed as a paradoxical consequence of progress in modern societies, where behavioural changes have restrained early microbial exposure. This engenders an evolutionary mismatch between historical adaptations of the immune system and contemporary lifestyles. Childhood ALL may be a preventable cancer.
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Affiliation(s)
- Mel Greaves
- Centre for Evolution and Cancer, The Institute of Cancer Research, London, UK.
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7
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Shahriari M, Jafari M, Khalafi M, Ramezani M, Maki M, Hosseinpour Soleimani F, Khadem P, Ghorbani P, Allahverdi Khani M, Shahverdi E. Pre- and Post- birth Causes of Acute Lymphoblastic Leukemia. Int J Cancer Manag 2018; 11. [DOI: 10.5812/ijcm.66448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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8
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Hwee J, Tait C, Sung L, Kwong JC, Sutradhar R, Pole JD. A systematic review and meta-analysis of the association between childhood infections and the risk of childhood acute lymphoblastic leukaemia. Br J Cancer 2017; 118:127-137. [PMID: 29065105 PMCID: PMC5765221 DOI: 10.1038/bjc.2017.360] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 01/02/2023] Open
Abstract
Background: To determine whether childhood infections were associated with the development of childhood acute lymphoblastic leukaemia (ALL). Methods: We included studies that assessed any infection in childhood prior to the diagnosis of ALL in children aged 0–19 years compared to children without cancer. The primary analysis synthesised any infection against the odds of ALL, and secondary analyses assessed the frequency, severity, timing of infections, and specific infectious agents against the odds of ALL. Subgroup analyses by data source were investigated. Results: In our primary analysis of 12 496 children with ALL and 2 356 288 children without ALL from 38 studies, we found that any infection was not associated with ALL (odds ratio (OR)=1.10, 95% CI: 0.95–1.28). Among studies with laboratory-confirmed infections, the presence of infections increased the odds of ALL by 2.4-fold (OR=2.42, 95% CI: 1.54–3.82). Frequency, severity, and timing of infection were not associated with ALL. Conclusions: The hypothesis put forward by Greaves and others about an infectious aetiology are neither confirmed nor refuted and the overall evidence remains inadequate for good judgement. The qualitative difference in the subgroup effects require further study, and future research will need to address the challenges in measuring infectious exposures.
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Affiliation(s)
- Jeremiah Hwee
- Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, 155 College Street, Toronto, ON, Canada
| | - Christopher Tait
- Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, 155 College Street, Toronto, ON, Canada
| | - Lillian Sung
- Division of Haematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada.,Program in Child Health Evaluative Sciences, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, 686 Bay Street, Toronto, ON, Canada.,Institute of Health Policy, Management and Evaluation, University of Toronto, Health Sciences Building, 155 College Street, Toronto, ON, Canada
| | - Jeffrey C Kwong
- Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, 155 College Street, Toronto, ON, Canada.,Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, ON, Canada.,Department of Family and Community Medicine, University of Toronto, Toronto, ON Canada.,Public Health Ontario, Toronto, ON, Canada.,Toronto Western Family Health Team, University Health Network, Toronto, ON, Canada
| | - Rinku Sutradhar
- Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, 155 College Street, Toronto, ON, Canada.,Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, ON, Canada
| | - Jason D Pole
- Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, 155 College Street, Toronto, ON, Canada.,Pediatric Oncology Group of Ontario, 480 University Avenue, Suite 1014, Toronto, ON, Canada
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9
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Timms JA, Relton CL, Rankin J, Strathdee G, McKay JA. DNA methylation as a potential mediator of environmental risks in the development of childhood acute lymphoblastic leukemia. Epigenomics 2016; 8:519-36. [PMID: 27035209 PMCID: PMC4928498 DOI: 10.2217/epi-2015-0011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 01/22/2016] [Indexed: 11/21/2022] Open
Abstract
5-year survival rate for childhood acute lymphoblastic leukemia (ALL) has risen to approximately 90%, yet the causal disease pathway is still poorly understood. Evidence suggests multiple 'hits' are required for disease progression; an initial genetic abnormality followed by additional secondary 'hits'. It is plausible that environmental influences may trigger these secondary hits, and with the peak incidence of diagnosis between 2 and 5 years of age, early life exposures are likely to be key. DNA methylation can be modified by many environmental exposures and is dramatically altered in cancers, including childhood ALL. Here we explore the potential that DNA methylation may be involved in the causal pathway toward disease by acting as a mediator between established environmental factors and childhood ALL development.
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Affiliation(s)
- Jessica A Timms
- Institute of Health & Society, Newcastle University, Newcastle, UK
| | - Caroline L Relton
- MRC Integrative Epidemiology Unit, School of Social & Community Medicine, University of Bristol, UK
| | - Judith Rankin
- Institute of Health & Society, Newcastle University, Newcastle, UK
| | - Gordon Strathdee
- Northern Institute for Cancer Research, Newcastle University, UK
| | - Jill A McKay
- Institute of Health & Society, Newcastle University, Newcastle, UK
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10
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Sudan M, Arah OA, Olsen J, Kheifets L. Reported associations between asthma and acute lymphoblastic leukemia: insights from a hybrid simulation study. Eur J Epidemiol 2016; 31:593-602. [PMID: 26861154 DOI: 10.1007/s10654-016-0126-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 02/02/2016] [Indexed: 02/07/2023]
Abstract
Numerous studies have reported a protective association between asthma and acute lymphoblastic leukemia (ALL), but the causal structure of this association remains unclear. We present a hybrid simulation to examine the compatibility of this association with uncontrolled confounding by infection or another unmeasured factor. We generated a synthetic cohort using inputs on the interrelations of asthma, ALL, infections, and other suggested risk factors from the literature and the Danish National Birth Cohort. We computed odds ratios (ORs) between asthma and ALL in the synthetic cohort with and without adjustment for infections and other (including unmeasured) confounders. Only if infection was an extremely strong risk factor for asthma (OR of 10) and an extremely strong protective factor against ALL (OR of 0.1) was the asthma-ALL association compatible with the literature (OR of 0.78). Similarly, strong uncontrolled confounding by an unmeasured factor could downwardly bias the asthma-ALL association, but not enough to replicate findings in the literature. This investigation illustrates that the reported protective association between asthma and ALL is unlikely to be entirely due to uncontrolled confounding by infections or an unmeasured confounder alone. Simulation can be used to advance our understanding of risk factors for rare outcomes as demonstrated by this study.
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11
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Rudant J, Lightfoot T, Urayama KY, Petridou E, Dockerty JD, Magnani C, Milne E, Spector LG, Ashton LJ, Dessypris N, Kang AY, Miller M, Rondelli R, Simpson J, Stiakaki E, Orsi L, Roman E, Metayer C, Infante-Rivard C, Clavel J. Childhood acute lymphoblastic leukemia and indicators of early immune stimulation: a Childhood Leukemia International Consortium study. Am J Epidemiol 2015; 181:549-62. [PMID: 25731888 DOI: 10.1093/aje/kwu298] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 09/29/2014] [Indexed: 01/04/2023] Open
Abstract
The associations between childhood acute lymphoblastic leukemia (ALL) and several proxies of early stimulation of the immune system, that is, day-care center attendance, birth order, maternally reported common infections in infancy, and breastfeeding, were investigated by using data from 11 case-control studies participating in the Childhood Leukemia International Consortium (enrollment period: 1980-2010). The sample included 7,399 ALL cases and 11,181 controls aged 2-14 years. The data were collected by questionnaires administered to the parents. Pooled odds ratios and 95% confidence intervals were estimated by unconditional logistic regression adjusted for age, sex, study, maternal education, and maternal age. Day-care center attendance in the first year of life was associated with a reduced risk of ALL (odds ratio = 0.77, 95% confidence interval: 0.71, 0.84), with a marked inverse trend with earlier age at start (P < 0.0001). An inverse association was also observed with breastfeeding duration of 6 months or more (odds ratio = 0.86, 95% confidence interval: 0.79, 0.94). No significant relationship with a history of common infections in infancy was observed even though the odds ratio was less than 1 for more than 3 infections. The findings of this large pooled analysis reinforce the hypothesis that day-care center attendance in infancy and prolonged breastfeeding are associated with a decreased risk of ALL.
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12
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Ajrouche R, Rudant J, Orsi L, Petit A, Baruchel A, Lambilliotte A, Gambart M, Michel G, Bertrand Y, Ducassou S, Gandemer V, Paillard C, Saumet L, Blin N, Hémon D, Clavel J. Childhood acute lymphoblastic leukaemia and indicators of early immune stimulation: the Estelle study (SFCE). Br J Cancer 2015; 112:1017-26. [PMID: 25675150 PMCID: PMC4366894 DOI: 10.1038/bjc.2015.53] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/04/2015] [Accepted: 01/12/2015] [Indexed: 11/29/2022] Open
Abstract
Background: Factors related to early stimulation of the immune system (breastfeeding, proxies for exposure to infectious agents, normal delivery, and exposure to animals in early life) have been suggested to decrease the risk of childhood acute lymphoblastic leukaemia (ALL). Methods: The national registry-based case–control study, ESTELLE, was carried out in France in 2010–2011. Population controls were frequency matched with cases on age and gender. The participation rates were 93% for cases and 86% for controls. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios (OR) were estimated using unconditional regression models adjusted for age, gender, and potential confounders. Results: In all, 617 ALL and 1225 controls aged ⩾1 year were included. Inverse associations between ALL and early common infections (OR=0.8, 95% confidence interval (CI): 0.6, 1.0), non-first born (⩾3 vs 1; OR=0.7, 95% CI: 0.5, 1.0), attendance of a day-care centre before age 1 year (OR=0.7, 95% CI: 0.5, 1.0), breastfeeding (OR=0.8, 95% CI: 0.7, 1.0), and regular contact with pets (OR=0.8, 95% CI: 0.7, 1.0) in infancy were observed. Conclusions: The results support the hypothesis that conditions promoting the maturation of the immune system in infancy have a protective role with respect to ALL.
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Affiliation(s)
- R Ajrouche
- 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Sud University, Le Kremlin Bicêtre, France
| | - J Rudant
- 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France [3] RNHE-National Registry of Childhood Hematopoietic Malignancies, Villejuif, France
| | - L Orsi
- 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France
| | - A Petit
- 1] AP-HP, Hôpital Armand Trousseau, Paris, France [2] Université Paris 6 Pierre et Marie Curie, Paris, France
| | - A Baruchel
- 1] AP-HP, Hôpital Robert Debré, Paris, France [2] Université Paris 7, Paris, France
| | | | - M Gambart
- Hôpital des Enfants, Toulouse, France
| | - G Michel
- AP-HM, Hôpital la Timone, Marseille, France
| | - Y Bertrand
- Institut d'Hématologie et d'Oncologie Pédiatrique, Lyon, France
| | - S Ducassou
- Hôpital Pellegrin Tripode, Bordeaux, France
| | | | - C Paillard
- Hôpital de Hautepierre, Strasbourg, France
| | - L Saumet
- Hôpital Arnaud de Villeneuve, Montpellier, France
| | - N Blin
- Hôpital Mère-Enfant, CHU-Nantes, Nantes, France
| | - D Hémon
- 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France
| | - J Clavel
- 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France [3] RNHE-National Registry of Childhood Hematopoietic Malignancies, Villejuif, France
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13
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Abstract
The causes of childhood cancer have been systematically studied for decades, but apart from high-dose radiation and prior chemotherapy there are few strong external risk factors. However, inherent risk factors including birth weight, parental age, and congenital anomalies are consistently associated with most types of pediatric cancer. Recently the contribution of common genetic variation to etiology has come into focus through genome-wide association studies. These have highlighted genes not previously implicated in childhood cancers and have suggested that common variation explains a larger proportion of childhood cancers than adult. Rare variation and nonmendelian inheritance may also contribute to childhood cancer risk but have not been widely examined.
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Affiliation(s)
- Logan G. Spector
- Division of Epidemiology/Clinical Research Department of Pediatrics University of Minnesota 420 Delaware Street, SE, MMC 715 Minneapolis, MN 55455
| | - Nathan Pankratz
- Department of Lab Medicine and Pathology University of Minnesota
| | - Erin L. Marcotte
- Division of Epidemiology/Clinical Research Department of Pediatrics University of Minnesota
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14
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Mezei G, Sudan M, Izraeli S, Kheifets L. Epidemiology of childhood leukemia in the presence and absence of Down syndrome. Cancer Epidemiol 2014; 38:479-89. [DOI: 10.1016/j.canep.2014.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 07/10/2014] [Accepted: 07/11/2014] [Indexed: 02/05/2023]
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15
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Maia RDRP, Wünsch Filho V. Infection and childhood leukemia: review of evidence. Rev Saude Publica 2014; 47:1172-85. [PMID: 24626555 PMCID: PMC4206105 DOI: 10.1590/s0034-8910.2013047004753] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 07/09/2013] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To analyze studies that evaluated the role of infections as well as indirect
measures of exposure to infection in the risk of childhood leukemia,
particularly acute lymphoblastic leukemia. METHODS A search in Medline, Lilacs, and SciELO scientific publication databases
initially using the descriptors "childhood leukemia" and "infection" and
later searching for the words "childhood leukemia" and "maternal infection
or disease" or "breastfeeding" or "daycare attendance" or "vaccination"
resulted in 62 publications that met the following inclusion criteria:
subject aged ≤ 15 years; specific analysis of cases diagnosed with acute
lymphoblastic leukemia or total leukemia; exposure assessment of mothers' or
infants' to infections (or proxy of infection), and risk of leukemia. RESULTS Overall, 23 studies that assessed infections in children support the
hypothesis that occurrence of infection during early childhood reduces the
risk of leukemia, but there are disagreements within and between studies.
The evaluation of exposure to infection by indirect measures showed evidence
of reduced risk of leukemia associated mainly with daycare attendance. More
than 50.0% of the 16 studies that assessed maternal exposure to infection
observed increased risk of leukemia associated with episodes of influenza,
pneumonia, chickenpox, herpes zoster, lower genital tract infection, skin
disease, sexually transmitted diseases, Epstein-Barr virus, and
Helicobacter pylori. CONCLUSIONS Although no specific infectious agent has been identified, scientific
evidence suggests that exposure to infections has some effect on childhood
leukemia etiology.
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Abstract
BACKGROUND Epidemiologic studies indicate that infections in early childhood may protect against pediatric acute lymphoblastic leukemia (ALL). METHODS We identified 3,402 ALL cases among children 0 to 5 years of age using the California Cancer Registry. From California birth records we randomly selected controls in a 20:1 ratio and frequency matched them to cases by birth year. We investigated markers of exposure to infections, including month of birth, timing of birth in relation to influenza and respiratory syncytial virus (RSV) seasons, and birth order based on data from California birth certificates and national infection surveillance systems. RESULTS We observed an increased risk of ALL for spring and summer births, and for those first exposed to an influenza or RSV season at nine to twelve months of age compared with those exposed during the first three months of life, and this association was stronger among first born children [odds ratios (OR), 1.44 and 95% confidence intervals (CI), 1.13-1.82, for influenza exposure at nine to twelve months of age]. Decreased risk was observed with increasing birth order among non-Hispanic whites but not Hispanics (OR, 0.76 and 95% CI, 0.59-096, for fourth or higher birth order among whites). CONCLUSION Our results support the hypothesis that infections in early childhood decrease risk of ALL. IMPACT Our findings implicate early life exposure to infections as protective factors for ALL in young children.
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Affiliation(s)
- Erin L Marcotte
- Authors' Affiliations: Department of Pediatrics, Division of Epidemiology and Clinical Research, University of Minnesota, Minneapolis, Minnesota; Departments of
| | | | - Myles Cockburn
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Fei Yu
- Biostatistics, Fielding School of Public Health, University of California; and
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17
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Abstract
Healthy infants and toddlers who attend day care centers are at increased risk for contracting common childhood illnesses such as viral upper and lower respiratory illnesses, viral gastrointestinal infections, and acute and chronic otitis media. The author proposes that this high frequency of common infections be termed daycaritis. Daycaritis imposes significant social and economic burdens on both the family and the health care system. This review describes the most common infections seen in day care attendees, preventative measures to decrease the rates of illness, and a practical approach to diagnosis and management in the emergency department.
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Affiliation(s)
- Pamela Bailey
- Section of Emergency Medicine, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX
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18
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Vestergaard TR, Rostgaard K, Grau K, Schmiegelow K, Hjalgrim H. Hospitalisation for infection prior to diagnosis of acute lymphoblastic leukaemia in children. Pediatr Blood Cancer 2013; 60:428-32. [PMID: 22915267 DOI: 10.1002/pbc.24286] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 07/16/2012] [Indexed: 01/27/2023]
Abstract
BACKGROUND It has been proposed that infections in infancy and early childhood are associated with a reduced risk of childhood acute lymphoblastic leukaemia (ALL). We tested this hypothesis in a register-based study of hospitalisations for infectious diseases prior to diagnosis of childhood ALL. PROCEDURE A nation-wide cohort encompassing all Danish children aged 0-14 years and born between 1977 and 2008 (N = 1,778,129) was established and followed for hospitalisations for infectious diseases and risk of childhood ALL. The exposure was lagged 1 year to limit reverse causality. In the statistical analyses exposure was defined as (time dependent) number of early or late (before 2 or at/after 2 years of age) hospitalisations to further explore possible age-dependent associations. RESULTS A total of 815 children were diagnosed with ALL during follow-up. Risk of ALL was associated neither with hospitalisations for infectious diseases before (incidence rate ratio = 0.92, 95% confidence interval 0.78-1.07) nor at/after 2 years of age (incidence rate ratio = 1.04, 95% confidence interval 0.81-1.32). This also applied to subsets of ALL supposedly initiated prenatally. CONCLUSION The absence of association between hospitalisation for infections and risk of childhood ALL directs future investigations of the role of infections in development of childhood ALL towards exploration of less severe infections.
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19
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Chang JS, Tsai YW, Tsai CR, Wiemels JL. Allergy and risk of childhood acute lymphoblastic leukemia: a population-based and record-based study. Am J Epidemiol 2012; 176:970-8. [PMID: 23171876 DOI: 10.1093/aje/kws263] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A deficit of normal immune stimulation in early childhood is a suspected risk factor for both childhood acute lymphoblastic leukemia (ALL) and allergies. The present study utilized a population-based case-control design using medical claims data from the National Health Insurance Research Database of Taiwan to evaluate the association between allergy and childhood leukemia. Eight hundred forty-six childhood ALL patients who were newly diagnosed during 2000 to 2008 and were older than 1 but less than 10 years of age were individually matched with 3,374 controls based on sex, birth date, and time of diagnosis (reference date for the controls). Conditional logistic regression was performed to assess the association between childhood ALL and allergies. An increased risk of ALL was observed with having an allergy less than 1 year before the case's ALL diagnosis (odds ratio (OR) = 1.7, 95% confidence interval (CI): 1.5, 2.0), more than 1 year before the case's diagnosis (OR = 1.3, 95% CI: 1.1, 1.5), and before the age of 1 year (OR = 1.4, 95% CI: 1.1, 1.7). These results suggest that the pathogenesis of childhood ALL and allergy share a common biologic mechanism.
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Affiliation(s)
- Jeffrey S Chang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan.
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20
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Crouch S, Lightfoot T, Simpson J, Smith A, Ansell P, Roman E. Infectious illness in children subsequently diagnosed with acute lymphoblastic leukemia: modeling the trends from birth to diagnosis. Am J Epidemiol 2012; 176:402-8. [PMID: 22899827 DOI: 10.1093/aje/kws180] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Although there is increasing evidence that immune dysregulation in children who develop acute lymphoblastic leukemia (ALL) is detectable from birth, debate about the role of infectious exposures in infancy continues. With the aim of quantifying children's infectious exposures, investigators have used a number of infection exposure proxies, but there is a lack of consistency in findings, with some markers indicating increased ALL risks and others decreased risks, the disparity being evident both within and between studies. Accordingly, the authors conducted an in-depth analysis of key infection exposure proxies used in the United Kingdom Childhood Cancer Study, a national population-based case-control study conducted over the period 1991-1996, which combined data from medical records, parental interview, and population census. This longitudinal approach revealed the marked deterioration in immune response that emerged around 5 months prior to ALL diagnosis and confirmed that infectious diagnoses in the first year of life were significantly increased (P < 0.05) in children who developed leukemia between 2 and 14 years of age, as well as in those who had birth orders >1, were not breastfed, lived in deprived areas, or were diagnosed with eczema. By contrast, no association between infectious illness and preschool activity was detected, the lower infection levels among controls whose mothers reported attendance contributing to a significantly reduced ALL odds ratio.
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Affiliation(s)
- Simon Crouch
- Epidemiology & Cancer Statistics Group, Department of Health Sciences, University of York, Heslington, York, United Kingdom.
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21
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Chang JS, Tsai CR, Tsai YW, Wiemels JL. Medically diagnosed infections and risk of childhood leukaemia: a population-based case-control study. Int J Epidemiol 2012; 41:1050-9. [PMID: 22836110 DOI: 10.1093/ije/dys113] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Previous studies on the association between childhood infections and childhood leukaemia have produced inconsistent results, likely due to the recall error/bias of infection data reported by the parents. The current study used a population-based and record-based case-control design to evaluate the association between childhood leukaemia and infections using the National Health Insurance Research Database of Taiwan. METHODS In all, 846 childhood acute lymphoblastic leukaemia (ALL) and 193 acute myeloid leukaemia (AML) patients newly diagnosed between 2000 and 2008, aged >1 and <10 years, were included. Up to four controls (3374 for ALL and 766 for AML) individually matched to each case on sex, birth date and time of diagnosis (reference date for the controls) were identified. Conditional logistic regression was performed to assess the association between childhood leukaemia and infections. RESULTS Having any infection before 1 year of age was associated with an increased risk for both childhood ALL (odds ratio = 3.2, 95% confidence interval 2.2-4.7) and AML (odds ratio = 6.0, 95% confidence interval 2.0-17.8), with a stronger risk associated with more episodes of infections. Similar results were observed for infections occurring >1 year before the cases' diagnosis of childhood leukaemia. CONCLUSIONS Children with leukaemia may have a dysregulated immune function present at an early age, resulting in more episodes of symptomatic infections compared with healthy controls. However, confounding by other infectious measures such as birth order and day care attendance could not be ruled out. Finally, the results are only relevant to the medically diagnosed infections.
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Affiliation(s)
- Jeffrey S Chang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan, ROC.
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22
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Urayama KY, Ma X, Selvin S, Metayer C, Chokkalingam AP, Wiemels JL, Does M, Chang J, Wong A, Trachtenberg E, Buffler PA. Early life exposure to infections and risk of childhood acute lymphoblastic leukemia. Int J Cancer 2010; 128:1632-43. [PMID: 21280034 DOI: 10.1002/ijc.25752] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 10/12/2010] [Indexed: 11/06/2022]
Abstract
Evidence from a growing number of studies indicates that exposure to common infections early in life may be protective against childhood acute lymphoblastic leukemia (ALL). We examined the relationship between three measures of early life exposure to infections-daycare attendance, birth order and common childhood infections in infancy-with the risk of ALL in non-Hispanic white and Hispanic children, two ethnicities that show sociodemographic differences. The analysis included 669 ALL cases (284 non-Hispanic whites and 385 Hispanics) and 977 controls (458 non-Hispanic whites and 519 Hispanics) ages 1-14 years enrolled in the Northern California Childhood Leukemia Study (NCCLS). When the three measures were evaluated separately, daycare attendance by the age of 6 months (odds ratio [OR] for each thousand child-hours of exposure = 0.90, 95% confidence interval [CI]: 0.82-1.00) and birth order (OR for having an older sibling = 0.68, 95% CI: 0.50-0.92) were associated with a reduced risk of ALL among non-Hispanic white children but not Hispanic children, whereas ear infection before age 6 months was protective in both ethnic groups. When the three measures were assessed simultaneously, the influence of daycare attendance (OR = 0.83, 95% CI: 0.73-0.94) and having an older sibling (OR = 0.59, 95% CI: 0.43-0.83) became stronger for non-Hispanic white children. In Hispanic children, a strong reduction in risk associated with ear infections persisted (OR = 0.45, 95% CI: 0.25-0.79). Evidence of a protective role for infection-related exposures early in life is supported by findings in both the non-Hispanic white and Hispanic populations within the NCCLS.
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Affiliation(s)
- Kevin Y Urayama
- School of Public Health, University of California, Berkeley, CA, USA.
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23
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Rudant J, Orsi L, Menegaux F, Petit A, Baruchel A, Bertrand Y, Lambilliotte A, Robert A, Michel G, Margueritte G, Tandonnet J, Mechinaud F, Bordigoni P, Hémon D, Clavel J. Childhood acute leukemia, early common infections, and allergy: The ESCALE Study. Am J Epidemiol 2010; 172:1015-27. [PMID: 20807738 DOI: 10.1093/aje/kwq233] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
This study investigated the role of factors considered related to early stimulation of the immune system in the etiology of childhood acute leukemia. The national registry-based case-control study ESCALE was carried out in France in 2003-2004. Population controls were frequency matched to cases on age and gender. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios were estimated using unconditional regression models adjusted for potential confounders. Included were 634 acute lymphoblastic leukemia cases, 86 acute myeloblastic leukemia cases, and 1,494 controls aged ≥1 year. Negative associations were observed between acute lymphoblastic leukemia and birth order (P for trend < 0.0001), attendance at a day-care center before age 1 year (odds ratio (OR) = 0.8, 95% confidence interval (CI): 0.6, 1.1), prolonged breastfeeding (OR = 0.7, 95% CI: 0.5, 1.0), repeated early common infections (OR = 0.7, 95% CI: 0.6, 0.9), regular contact with farm animals (OR = 0.6, 95% CI: 0.5, 0.8), frequent farm visits in early life (OR = 0.4, 95% CI: 0.3, 0.6), and history of asthma (OR = 0.7, 95% CI: 0.4, 1.0) or eczema (OR = 0.7, 95% CI: 0.6, 0.9). Results support the hypothesis that repeated early infections and asthma may play a role against childhood acute leukemia.
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Affiliation(s)
- Jérémie Rudant
- CESP Centre for Research in Epidemiology and Population Health, INSERM, Villejuif, France
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24
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Chang JS, Wiemels JL, Chokkalingam AP, Metayer C, Barcellos LF, Hansen HM, Aldrich MC, Guha N, Urayama KY, Scélo G, Green J, May SL, Kiley VA, Wiencke JK, Buffler PA. Genetic polymorphisms in adaptive immunity genes and childhood acute lymphoblastic leukemia. Cancer Epidemiol Biomarkers Prev 2010; 19:2152-63. [PMID: 20716621 DOI: 10.1158/1055-9965.epi-10-0389] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Childhood acute lymphoblastic leukemia (ALL) has been hypothesized to have an infection- and immune-related etiology. The lack of immune priming in early childhood may result in abnormal immune responses to infections later in life and increase ALL risk. METHODS The current analyses examined the association between childhood ALL and 208 single-nucleotide polymorphisms (SNP) of 29 adaptive immune function genes among 377 ALL cases and 448 healthy controls. Single SNPs were analyzed with a log-additive approach using logistic regression models adjusted for sex, age, Hispanic ethnicity, and race. Sliding window haplotype analyses were done with haplotypes consisting of 2 to 6 SNPs. RESULTS Of the 208 SNPs, only rs583911 of IL12A, which encodes a critical modulator of T-cell development, remained significant after accounting for multiple testing (odds ratio for each copy of the variant G allele, 1.52; 95% confidence interval, 1.25-1.85; P = 2.9 x 10(-5)). This increased risk was stronger among firstborn children of all ethnicities and among non-Hispanic children with less day care attendance, consistent with the hypothesis about the role of early immune modulation in the development of childhood ALL. Haplotype analyses identified additional regions of CD28, FCGR2, GATA3, IL2RA, STAT4, and STAT6 associated with childhood ALL. CONCLUSION Polymorphisms of genes on the adaptive immunity pathway are associated with childhood ALL risk. IMPACT Results of this study support an immune-related etiology of childhood ALL. Further confirmation is required to detect functional variants in the significant genomic regions identified in this study, in particular for IL12A.
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Affiliation(s)
- Jeffrey S Chang
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA.
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25
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Urayama KY, Buffler PA, Gallagher ER, Ayoob JM, Ma X. A meta-analysis of the association between day-care attendance and childhood acute lymphoblastic leukaemia. Int J Epidemiol 2010; 39:718-32. [PMID: 20110276 PMCID: PMC2878455 DOI: 10.1093/ije/dyp378] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Childhood acute lymphoblastic leukaemia (ALL) may be the result of a rare response to common infection(s) acquired by personal contact with infected individuals. A meta-analysis was conducted to examine the relationship between day-care attendance and risk of childhood ALL, specifically to address whether early-life exposure to infection is protective against ALL. Methods Searches of the PubMed database and bibliographies of publications on childhood leukaemia and infections were conducted. Observational studies of any size or location and published in English resulted in the inclusion of 14 case–control studies. Results The combined odds ratio (OR) based on the random effects model indicated that day-care attendance is associated with a reduced risk of ALL [OR = 0.76, 95% confidence interval (CI): 0.67, 0.87]. In subgroup analyses evaluating the influence of timing of exposure, a similarly reduced effect was observed for both day-care attendance occurring early in life (≤2 years of age) (OR = 0.79, 95% CI: 0.65, 0.95) and day-care attendance with unspecified timing (anytime prior to diagnosis) (OR = 0.81, 95% CI: 0.70, 0.94). Similar findings were observed with seven studies in which common ALL were analysed separately. The reduced risk estimates persisted in sensitivity analyses that examined the sources of study heterogeneity. Conclusions This analysis provides strong support for an association between exposure to common infections in early childhood and a reduced risk of ALL. Implications of a ‘hygiene’-related aetiology suggest that some form of prophylactic intervention in infancy may be possible.
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Affiliation(s)
- Kevin Y Urayama
- School of Public Health, University of California, Berkeley, CA 94720, USA.
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26
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Abstract
This review considers recent studies regarding the role of environmental factors in the etiology of childhood leukemia and lymphoma. Potential environmental risk factors identified for childhood leukemia include exposure to magnetic fields of more than 0.4 micro Tessla, exposure to pesticides, solvents, benzene and other hydrocarbons, maternal alcohol consumption (but only for certain genotypes), contaminated drinking water, infections, and high birth weight. The finding of space-time clustering and seasonal variation also supports a role for infections. There is little evidence linking childhood leukemia with lifetime exposure to ionizing radiation although fetal exposures to X-rays are associated with increased risk. Breast-feeding, consumption of fresh fruit and vegetables and having allergies all appear to be protective. Burkitt lymphoma (BL) is confined to areas of the world where malaria is endemic, with the additional involvement of the Epstein-Barr virus (EBV) as a co-factor. Environmental risk factors suggested for other types of non-Hodgkin lymphoma (NHL) include exposure to ionizing radiation (both lifetime and antenatal), pesticides, and, in utero exposure to cigarette smoke, benzene and nitrogen dioxide (via the mother). Hodgkin lymphoma (HL) is especially associated with higher levels of socioeconomic deprivation, but breast-feeding seems to confer lower risk. This is consistent with an infection or immune-response mediated etiology for HL.
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Affiliation(s)
- Richard J Q McNally
- School of Clinical Medical Sciences, Child Health, University of Newcastle Upon Tyne, UK.
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27
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Roman E, Simpson J, Ansell P, Lightfoot T, Smith A. Infectious proxies and childhood leukaemia: Findings from the United Kingdom Childhood Cancer Study (UKCCS). Blood Cells Mol Dis 2009; 42:126-8. [DOI: 10.1016/j.bcmd.2008.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/18/2008] [Indexed: 11/20/2022]
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28
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Ma X, Urayama K, Chang J, Wiemels JL, Buffler PA. Infection and pediatric acute lymphoblastic leukemia. Blood Cells Mol Dis 2008; 42:117-20. [PMID: 19064328 DOI: 10.1016/j.bcmd.2008.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/18/2008] [Indexed: 10/21/2022]
Abstract
In this review, we provide an overview of recent findings from the Northern California Childhood Leukemia Study (NCCLS) on factors related to the immune system including child's vaccination history and measures of child's exposure to infectious agents, namely daycare attendance, infection during infancy, and parental social contact in the work place. We also provide suggestions for the next stages of studies.
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Affiliation(s)
- Xiaomei Ma
- Department of Epidemiology and Public Health, Yale University School of Medicine, 60 College Street, New Haven, CT 06520-8034, USA.
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29
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Abstract
Three hypotheses have proposed the involvement of infections in the aetiology of childhood leukaemia, suggesting either a specific leukaemogenic infection or a series of common infections that lead to a dysregulation of the immune system. Much of the evidence for the link with infections has been based on epidemiological observations, often using proxy measures of infection. Proxy measures include population mixing, parental occupation, age distribution of incidence, spatial and space-time clustering of cases, birth order and day care during infancy. This paper discusses the proxies used and examines to what extent a commonly used proxy measure, birth order, is a fair representation of either specific infections or general infectious load. It is clear that although leukaemia, and other diseases, may be linked with infections, one needs to (1) measure specific and general infections with more accuracy and (2) understand how proxy measures relate to real infections in the population.
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Affiliation(s)
- Graham Richard Law
- Biostatistics Unit, Centre for Epidemiology and Biostatistics, Room 8.01, Worsley Building, University of Leeds, Leeds LS2 9LN, UK.
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30
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Abstract
There is growing evidence supporting a role for infections in the aetiology of childhood leukaemia. Hypotheses proposed by both Greaves and Kinlen describe childhood leukaemia to be a rare response to one or more common infections acquired through personal contacts. Previous epidemiological studies have used day-care attendance as an indicator of the increased likelihood of early and frequent exposure to infections. It is well-documented that in developed countries, exposures to common infections occur more frequently in this type of setting. Within the Northern California Childhood Leukaemia Study, the role of social contact has been assessed and a unique 'child-hours' summary measure incorporating information on the number of months attending a day-care, mean hours per week at this day-care and the number of children in the day-care setting was constructed. In this review, the previously reported day-care results have been described, showing that in non-Hispanic White children, children in the highest category of total child-hours of exposure had a reduced risk of acute lymphoblastic leukaemia (ALL), particularly common B-cell precursor ALL (c-ALL), compared with children without such exposures, with evidence of a dose-response effect. In addition, a literature review of relevant studies has been conducted, examining the relationship between day-care attendance and risk of childhood ALL. Overall, the 14 studies identified provided consistent support for this hypothesis, with the majority of studies reporting some evidence of a reduced risk. A meta-analysis is currently underway, which will provide a quantitative evaluation of the overall consistency and strength of the association between day-care attendance or social contact and risk of childhood ALL.
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Affiliation(s)
- Kevin Y Urayama
- School of Public Health, University of California, Berkeley, 2150 Shattuck Avenue, Suite 500, Berkeley, CA 94704, USA.
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31
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Abstract
Leukemia is the most common childhood cancer and a major source of morbidity and mortality. The etiology of childhood leukemia remains largely unknown. Cytogenetic abnormalities determine disease subtypes, prognosis, clinical presentation, and course and may help in discovering etiological factors. Epidemiologic investigations of leukemia are complicated by many factors, including the rarity of the disease, necessitating careful study design. Two emerging areas of interest in leukemia etiology are birth weight and diet. High birth weight has been associated with increased risk of childhood leukemia. The biological mechanism behind this association may involve insulin-like growth factor I (IGF-I), which is associated with high birth weight. IGF-I may act by increasing the absolute number of stem cells available for transformation, stimulating the growth of cells that are already transformed, or a combination of effects. Diet has been linked with leukemia. Maternal dietary DNA topoisomerase II (DNAt2) inhibitor intake is associated with infant acute myeloid leukemia (AML) with the MLL gene translocation. Increased intake of fruits and vegetables has been associated with decreased leukemia risk and, relatedly, lack of maternal folate supplementation has been associated with increased childhood leukemia risk, possibly by causing DNA hypomethylation and increased DNA strand breaks. Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms modify this risk.
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Affiliation(s)
- Richard L Tower
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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32
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Cardwell CR, McKinney PA, Patterson CC, Murray LJ. Infections in early life and childhood leukaemia risk: a UK case-control study of general practitioner records. Br J Cancer 2008; 99:1529-33. [PMID: 18827817 DOI: 10.1038/sj.bjc.6604696] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We investigated infections in early life (diagnosed in general practice) and subsequent risk of childhood leukaemia in the UK General Practice Research Database (GPRD). All children born at GPRD practices and subsequently diagnosed with leukaemia were identified as cases and were individually matched (on year of birth, sex and practice) to up to 20 controls. The final analysis included 162 leukaemia cases and 2215 matched controls. Conditional logistic regression demonstrated no evidence that children with one or more recorded infection in the first year of life had a reduced risk of leukaemia (OR=1.05, 95%CI 0.69, 1.59; P=0.83) or acute lymphoblastic leukaemia (ALL; OR=1.05, 95%CI 0.64–1.74; P=0.84). Our study provides no support for the Greaves hypothesis, which proposes that reduced or delayed exposure to infections in early life increases the risk of childhood ALL.
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33
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Harding NJ, Birch JM, Hepworth SJ, McKinney PA. Infectious exposure in the first year of life and risk of central nervous system tumors in children: analysis of day care, social contact, and overcrowding. Cancer Causes Control 2008; 20:129-36. [DOI: 10.1007/s10552-008-9224-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 08/14/2008] [Indexed: 12/20/2022]
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34
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Abstract
There is growing evidence that some chronic diseases are caused, or promoted, by infectious disease. 'Population mixing' has been used as a proxy for the range and dose of infectious agents circulating in a community. Given the speculation over the role of population mixing in many chronic diseases, we review the various methods used for measuring population mixing, and provide a classification of these. We recommend that authors fulfill two criteria in publications: measures are demonstrably associated with the putative risk factors for which population-mixing is acting as a proxy and fundamental characteristics of the chosen measures are clearly defined.
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Affiliation(s)
- Graham R Law
- Biostatistics Unit, University of Leeds, Leeds, UK
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35
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Simpson J, Smith A, Ansell P, Roman E. Childhood leukaemia and infectious exposure: a report from the United Kingdom Childhood Cancer Study (UKCCS). Eur J Cancer 2007; 43:2396-403. [PMID: 17826085 DOI: 10.1016/j.ejca.2007.07.027] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 07/24/2007] [Accepted: 07/31/2007] [Indexed: 12/01/2022]
Abstract
Data from a national case-control study are used to explore the relationships between childhood leukaemia, infant infection and three markers of infectious exposure - birth order, infant-activity group attendance and area-based deprivation. Amongst controls, clinically diagnosed infection in the first year varied little with birth order and infant-activity group attendance - with 4 in 5 children having at least one infection, and each child averaging around 2.9 (2.8-3.0). Amongst cases of acute lymphoblastic leukaemia (ALL), the levels of infection increased as the indices of infectious exposure increased - for example, odds ratios associated with at least one infection in the first year being 0.9 (95% confidence interval (CI): 0.6-1.4) for birth order one and 1.6 (95% CI: 1.1-2.2) for birth order two or more. By contrast, interview data were misleading, with mothers - particularly case mothers - consistently under-reporting. We conclude that the findings based on clinical data, combined with the markers of infectious exposure, confirm the observation that immune dysregulation among children who develop ALL is detectable from an early age.
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Affiliation(s)
- Jill Simpson
- Department of Health Sciences, University of York, YO10 5DD, UK.
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36
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Goodman M, Dana Flanders W. Study design options in evaluating gene-environment interactions: practical considerations for a planned case-control study of pediatric leukemia. Pediatr Blood Cancer 2007; 48:375-9. [PMID: 16874764 DOI: 10.1002/pbc.20933] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND We compare methodological approaches for evaluating gene-environment interaction using a planned study of pediatric leukemia as a practical example. We considered three design options: a full case-control study (Option I), a case-only study (Option II), and a partial case-control study (Option III), in which information on controls is limited to environmental exposure only. PROCEDURE For each design option we determined its ability to measure the main effects of environmental factor E and genetic factor G, and the interaction between E and G. Using the leukemia study example, we calculated sample sizes required to detect and odds ratio (OR) of 2.0 for E alone, an OR of 10 for G alone and an interaction G x E of 3. RESULTS Option I allows measuring both main effects and interaction, but requires a total sample size of 1,500 cases and 1,500 controls. Option II allows measuring only interaction, but requires just 121 cases. Option III allows calculating the main effect of E, and interaction, but not the main effect of G, and requires a total of 156 cases and 133 controls. CONCLUSIONS In this case, the partial case-control study (Option III) appears to be more efficient with respect to its ability to answer the research questions for the amount of resources required. The design options considered in this example are not limited to observational epidemiology and may be applicable in studies of pharmacogenomics, survivorship, and other areas of pediatric ALL research.
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Affiliation(s)
- Michael Goodman
- Department of Epidemiology Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, USA.
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Linet MS, Byrne J, Willis GB, Wacholder S, Forman MR. Maternal sensitivity concerning aetiological research into childhood cancer: results of preliminary focus groups. Paediatr Perinat Epidemiol 2007; 21:169-78. [PMID: 17302647 DOI: 10.1111/j.1365-3016.2007.00792.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We and others have postulated that modifications to epidemiological methods and tools could improve understanding of childhood cancer aetiology. We describe features of paediatric cancer that influence study design and data collection strategies, and examine determinants of the reproducibility and accuracy of mothers' responses to questionnaires, which are the primary source of risk factor information. Two focus group sessions with mothers of children with acute lymphoblastic leukaemia (ALL) and two with mothers of children with brain tumours were conducted to explore: the optimal time of day, method of administration, and location for the interview; the availability of alternative data sources; the interval between paediatric cancer diagnosis and epidemiological interview; and other features which may affect maternal interview responses. Mothers of children with both types of cancer preferred being interviewed at home during the evening and were willing to provide complete access to their offsprings' medical records. Emotional, socio-economic and perhaps cultural differences between the groups of mothers were exemplified by the willingness of mothers of children with ALL to participate in epidemiological interviews earlier in their child's treatment course and to provide greater access to maternal reproductive history records compared with mothers of children with brain tumours. Parental concerns about the difficult disease and treatment course of children with brain tumours were a key element in their decision to defer participating in epidemiological interviews for many months after their child's cancer diagnosis. We conclude that the focus group approach can contribute to a broad strategy for improving questionnaires and methods for conducting paediatric cancer epidemiological research.
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Affiliation(s)
- Martha S Linet
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Baethesda, MD 20892-7238, USA.
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Mallol-Mesnard N, Menegaux F, Auvrignon A, Auclerc MF, Bertrand Y, Nelken B, Robert A, Michel G, Margueritte G, Perel Y, Méchinaud F, Bordigoni P, Leverger G, Baruchel A, Hémon D, Clavel J. Vaccination and the risk of childhood acute leukaemia: the ESCALE study (SFCE). Int J Epidemiol 2007; 36:110-6. [PMID: 17227780 PMCID: PMC2292812 DOI: 10.1093/ije/dyl270] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In 2002, a poster alerted the French health authorities to the possibility that the risk of childhood leukaemia might be increased by hepatitis B vaccination. Elucidating the role of vaccination in the aetiology of childhood acute leukaemia (AL) was therefore included in the objectives of an ongoing national study. METHODS The ESCALE study was a French national population-based case-control study conducted in France in 2003 and 2004 in order to investigate the role of infectious, environmental and genetic factors in four childhood neoplastic diseases (leukaemia, lymphoma, neuroblastoma and brain tumour). The controls were randomly selected from the French population and age and gender frequency matched with the cases. A total of 776 cases of AL (91% of the eligible cases) and 1681 controls (71% of the eligible controls) were included. In a specific standardized telephone interview, which was the same for both the cases and controls, each mother was asked to read out her child's complete vaccination record. RESULTS No association between vaccination and the risk of childhood AL: acute lymphoblastic leukaemia or acute myeloblastic leukaemia was observed. No relationship between the risk of leukaemia and the type of vaccine, number of doses of each vaccine, total number of injections, total number of vaccine doses or number of early vaccinations was evidenced. No confounding factor was observed. CONCLUSION The study did not show any evidence of a role of vaccination in the aetiology of childhood leukaemia.
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Affiliation(s)
- Nathalie Mallol-Mesnard
- Epidémiologie environnementale des cancers
INSERM : U754INSERM : IFR69Université Paris Sud - Paris XI16, Avenue Paul Vaillant-Couturier
94807 VILLEJUIF CEDEX,FR
| | - Florence Menegaux
- Epidémiologie environnementale des cancers
INSERM : U754INSERM : IFR69Université Paris Sud - Paris XI16, Avenue Paul Vaillant-Couturier
94807 VILLEJUIF CEDEX,FR
| | - Anne Auvrignon
- Service d'hématologie-immunologie-oncologie pédiatrique
AP-HPHôpital Armand TrousseauUniversité Pierre et Marie Curie - Paris VI26, avenue du Docteur Arnold-Netter
75571 PARIS Cedex 12,FR
| | - Marie-Françoise Auclerc
- Service d'hématologie pédiatrique
AP-HPHôpital Saint-LouisUniversité Denis Diderot - Paris VIIParis,FR
| | | | - Brigitte Nelken
- Service d'Hématologie-Oncologie Pédiatrique
Hôpital Jeanne de FlandreCHRU LilleLille,FR
| | | | - Gérard Michel
- Hôpital La Timone
AP-HMHôpital La TimoneMarseille,FR
| | | | - Yves Perel
- Hôpital Pellegrin
CHU BordeauxBordeaux,FR
| | | | - Pierre Bordigoni
- Hôpital de Brabois
CHU NancyHôpital de BraboisUniversité Henri Poincaré - Nancy I54500 Vandoeuvre les Nancy,FR
| | - Guy Leverger
- Service d'hématologie-immunologie-oncologie pédiatrique
AP-HPHôpital Armand TrousseauUniversité Pierre et Marie Curie - Paris VI26, avenue du Docteur Arnold-Netter
75571 PARIS Cedex 12,FR
| | - André Baruchel
- Service d'hématologie pédiatrique
AP-HPHôpital Saint-LouisUniversité Denis Diderot - Paris VIIParis,FR
| | - Denis Hémon
- Epidémiologie environnementale des cancers
INSERM : U754INSERM : IFR69Université Paris Sud - Paris XI16, Avenue Paul Vaillant-Couturier
94807 VILLEJUIF CEDEX,FR
| | - Jacqueline Clavel
- Epidémiologie environnementale des cancers
INSERM : U754INSERM : IFR69Université Paris Sud - Paris XI16, Avenue Paul Vaillant-Couturier
94807 VILLEJUIF CEDEX,FR
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Abstract
Infections as well as environmental exposures are proposed determinants of childhood acute lymphoblastic leukemia (ALL), particularly common precursor B-cell ALL (cALL). Lines of investigation test hypotheses that cALL is a rarer result of common infection, that it results from uncommon infection, or that it ensues from abnormal immune development; perhaps it requires a preceding prenatal or early childhood insult. Ideally, studies should document that particular infections precede leukemiA and induce malignant transformation. However, limited detection studies have not directly linked specific human or nonhuman infectious agents with ALL or cALL. Primarily based on surrogate markers of infectious exposure, indirect evidence from ecologic and epidemiologic studies varies widely, but some suggest that infancy or early childhood infectious exposures might protect against childhood ALL or cALL. Several others suggest that maternal infection during pregnancy might increase risk or that certain breast-feeding practices decrease risk. To date, evidence cannot confirm or refute whether at least one infection induces or is a major co-factor for developing ALL or cALL, or perhaps actually protects against disease. Differences in methodology and populations studied may explain some inconsistencies. Other challenges to proof include the likely time lag between infection and diagnosis, the ubiquity of many infections, the influence of age at infection, and the limitations in laboratory assays; small numbers of cases, inaccurate background leukemia rates, and difficulty tracking mobile populations further affect duster investigations. Nevertheless, existing evidence partially supports plausibility and warrants further investigation into potential infectious determinants of ALL and cALL, particularly in the context of multifactorial or complex systems.
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Affiliation(s)
- Siobhán M O'Connor
- National Center for Infectious Diseases and National Center for HIV, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Altieri A, Castro F, Bermejo JL, Hemminki K. Number of siblings and the risk of lymphoma, leukemia, and myeloma by histopathology. Cancer Epidemiol Biomarkers Prev 2006; 15:1281-6. [PMID: 16835324 DOI: 10.1158/1055-9965.epi-06-0087] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Epidemiologic evidence indicates that several markers of exposure to childhood infections are inversely associated with the risk of childhood leukemia and lymphomas. We used the Swedish Family-Cancer Database to assess the effects of number of siblings on the risk of non-Hodgkin's (n = 7,007) and Hodgkin's lymphomas (n = 3,115), leukemias (n = 7,650), and multiple myeloma (n = 1,492) by histopathology. Poisson regression models included terms for age, sex, family history, period, and socioeconomic index. Having four or more siblings compared with none was associated with an excess risk of childhood acute lymphoblastic leukemia [ALL; rate ratio (RR), 2.11; P(trend) = 0.001], acute monocytic leukemia (RR, 2.51; P(trend) = 0.002), and multiple myeloma (RR, 1.34; P(trend) = 0.006). Having three or more older siblings compared with none decreased the risk of acute monocytic leukemia (RR, 0.35; P(trend) = 0.001) and childhood ALL (RR, 0.69; P(trend) = 0.01). The risk of Hodgkin's lymphoma for five or more older siblings compared with none was 0.41 (P(trend) = 0.003). Acute myeloid leukemia, chronic lymphocytic leukemia, and other lymphoproliferative malignancies were not associated with number of siblings. In conclusion, we found an excess risk of childhood ALL and acute monocytic leukemia in large families. However, for ALL, acute monocytic leukemia, and Hodgkin's lymphoma, younger siblings were strongly protected compared with older siblings. The remarkable protective effect of number of older siblings on acute monocytic leukemia is a novel finding of potential interest. Possible interpretations of our findings in the context of a putative infectious etiology are discussed.
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Affiliation(s)
- Andrea Altieri
- Division of Molecular Genetic Epidemiology, German Cancer Research Centre, Heidelberg
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41
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Paltiel O, Laniado DE, Yanetz R, Deutsch L, Calderon-Margalit R, Harlap S, Friedlander Y. The Risk of Cancer following Hospitalization for Infection in Infancy: A Population-Based Cohort Study. Cancer Epidemiol Biomarkers Prev 2006; 15:1964-8. [PMID: 17035406 DOI: 10.1158/1055-9965.epi-06-0313] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The relation between infections in infancy and subsequent cancer risk in children and young adults is controversial. Our aim was to examine this association in the Jerusalem Perinatal Study, a population-based cohort comprising all offspring from western Jerusalem and surroundings born from 1964 to 1976. METHODS Identity numbers of non-malformed singletons with recorded data about hospital admission in the 1st year of life (n = 24,554) were linked to the Population and Cancer Registries. Person-year incidence rates were calculated for the exposed (admitted for infection) and nonexposed (not admitted for infection) groups from birth to date of cancer diagnosis, death, or December 31, 2004. We used Cox proportional hazards models to adjust for covariates associated with hospitalization. RESULTS The median follow-up was 36 years. Cancer developed in 283 individuals. Hospitalization for infection was not associated with overall cancer risk [risk ratio (RR), 0.88; 95% confidence interval (95% CI), 0.56-1.37]. The incidence rate for non-Hodgkin's lymphoma was higher in the exposed compared with the nonexposed group (RR, 3.46; 95% CI, 1.38-8.68), remaining unchanged after controlling for birth weight, gender, and maternal education. Leukemia risk was not significantly associated (RR, 0.44; 95% CI, 0.06-3.24) with hospitalization for infection. CONCLUSIONS Hospital admission in the 1st year of life due to infection is associated with an increased risk of non-Hodgkin's lymphoma. This is consistent with observations that mild immunodeficiencies predispose to lymphoma. Survival of infants with subtle immune defects, who may have previously succumbed to their infection, may contribute to the increased incidence of non-Hodgkin's lymphoma observed over the last 50 years.
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Affiliation(s)
- Ora Paltiel
- School of Public Health and Community Medicine, Hadassah-Hebrew University Hospital, Jerusalem, Israel.
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42
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Abstract
The 'hygiene hypothesis' as originally formulated by Strachan, proposes that a cause of the recent rapid rise in atopic disorders could be a lower incidence of infection in early childhood, transmitted by unhygienic contact with older siblings. Use of the term 'hygiene hypothesis' has led to several interpretations, some of which are not supported by a broader survey of the evidence. The increase in allergic disorders does not correlate with the decrease in infection with pathogenic organisms, nor can it be explained by changes in domestic hygiene. A consensus is beginning to develop round the view that more fundamental changes in lifestyle have led to decreased exposure to certain microbial or other species, such as helminths, that are important for the development of immunoregulatory mechanisms. Although this review concludes that the relationship of the hypothesis to hygiene practice is not proven, it lends strong support to initiatives seeking to improve hygiene practice. It would however be helpful if the hypothesis were renamed, e.g. as the 'microbial exposure' hypothesis, or 'microbial deprivation' hypothesis, as proposed for instance by Bjorksten. Avoiding the term 'hygiene' would help focus attention on determining the true impact of microbes on atopic diseases, while minimizing risks of discouraging good hygiene practice.
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Affiliation(s)
- S F Bloomfield
- London School of Hygiene and Tropical Medicine, London, UK.
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Abstract
Childhood leukaemia is the principal subtype of paediatric cancer and, despite success in treatment, its causes remain enigmatic. A plethora of candidate environmental exposures have been proposed, but most lack a biological rationale or consistent epidemiological evidence. Although there might not be a single or exclusive cause, an abnormal immune response to common infection(s) has emerged as a plausible aetiological mechanism.
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Affiliation(s)
- Mel Greaves
- The Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, United Kingdom.
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44
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Ma X, Buffler PA, Wiemels JL, Selvin S, Metayer C, Loh M, Does MB, Wiencke JK. Ethnic difference in daycare attendance, early infections, and risk of childhood acute lymphoblastic leukemia. Cancer Epidemiol Biomarkers Prev 2005; 14:1928-34. [PMID: 16103439 DOI: 10.1158/1055-9965.epi-05-0115] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A role for infectious agents has been proposed in the etiology of childhood acute lymphoblastic leukemia (ALL), particularly for common ALL (c-ALL; ALL diagnosed in children ages 2-5 years and expressing CD10 and CD19 surface antigens). We evaluated the possible etiologic role of daycare attendance (a proxy measure for exposure to infectious agents) and infections during infancy in the Northern California Childhood Leukemia Study. A total of 294 incident ALL cases (ages 1-14 years) and 376 individually matched controls were included in this analysis. In non-Hispanic White children, daycare attendance measured by child-hours was associated with a significantly reduced risk of ALL. Compared with children who did not attend any daycare, the odds ratio (OR) for those who had >5,000 child-hours during infancy was 0.42 [95% confidence interval (95% CI), 0.18-0.99] for ALL and 0.33 (95% CI, 0.11-1.01) for c-ALL. Test for trend is also significant, which supports a dose-response relationship. The magnitude of effect associated with the same number of child-hours was stronger for daycare attendance during infancy than for daycare attendance before diagnosis. In addition, self-reported ear infection during infancy was associated with a significantly reduced risk of c-ALL (OR, 0.32; 95% CI, 0.14-0.74) in non-Hispanic White children. In Hispanic children, no association was observed among daycare attendance, early infections, and risk of childhood ALL or c-ALL. These results offer indirect yet strong support for the infectious disease hypothesis in the etiology of ALL in non-Hispanic White children and highlight an important ethnic difference.
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Affiliation(s)
- Xiaomei Ma
- Department of Epidemiology and Public Health, Yale University School of Medicine, 60 College Street, New Haven, CT 06520-8034, USA.
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45
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Gilham C, Peto J, Simpson J, Roman E, Eden TOB, Greaves MF, Alexander FE. Day care in infancy and risk of childhood acute lymphoblastic leukaemia: findings from UK case-control study. BMJ 2005; 330:1294. [PMID: 15849205 PMCID: PMC558199 DOI: 10.1136/bmj.38428.521042.8f] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/15/2005] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To test the hypothesis that reduced exposure to common infections in the first year of life increases the risk of developing acute lymphoblastic leukaemia. Design and setting The United Kingdom childhood cancer study (UKCCS) is a large population based case-control study of childhood cancer across 10 regions of the UK. PARTICIPANTS 6305 children (aged 2-14 years) without cancer; 3140 children with cancer (diagnosed 1991-6), of whom 1286 had acute lymphoblastic leukaemia (ALL). MAIN OUTCOME MEASURE Day care and social activity during the first year of life were used as proxies for potential exposure to infection in infancy. RESULTS Increasing levels of social activity were associated with consistent reductions in risk of ALL; a dose-response trend was seen. When children whose mothers reported no regular activity outside the family were used as the reference group, odds ratios for increasing levels of activity were 0.73 (95% confidence interval 0.62 to 0.87) for any social activity, 0.62 (0.51 to 0.75) for regular day care outside the home, and 0.48 (0.37 to 0.62) for formal day care (attendance at facility with at least four children at least twice a week) (P value for trend < 0.001). Although not as striking, results for non-ALL malignancies showed a similar pattern (P value for trend < 0.001). When children with non-ALL malignancies were taken as the reference group, a significant protective effect for ALL was seen only for formal day care (odds ratio = 0.69, 0.51 to 0.93; P = 0.02). Similar results were obtained for B cell precursor common ALL and other subgroups, as well as for cases diagnosed above and below age 5 years. CONCLUSION These results support the hypothesis that reduced exposure to infection in the first few months of life increases the risk of developing acute lymphoblastic leukaemia.
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Affiliation(s)
- C Gilham
- Cancer Research UK Epidemiology and Genetics Unit, Institute of Cancer Research, Sutton SM2 5NG
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46
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Abstract
Infectious disease histories were evaluated in a population-based case-control study of childhood acute lymphoblastic leukaemia (ALL) as it has been hypothesised that delays in early infections are associated with an increased risk of disease. Allergy histories were also assessed as part of a broader evaluation of the role of immune factors in ALL. Cases (n = 255) were diagnosed between 1980 and 1991 at one of four referral centres in a 31-county area of New York State; controls (n = 760) were a random sample of live births from the same region, frequency matched to cases by sex, race and birth year. Data were collected by mailed questionnaire, completed by case and control parents in 1995. Allergy and infectious histories before the age at leukaemia diagnosis for cases and an equivalent age for controls were evaluated. The adjusted odds ratio and 95% confidence interval [CI] associated with a positive history of any allergy was 0.58 [95% CI 0.38, 0.88] compared with a negative allergy history. The occurrence of several common childhood illnesses before 25 months of age and ALL were assessed, with both weak positive and weak inverse associations observed. Overall, these analyses provide little support for the hypothesis that infection delay in early life is associated with an increased risk of ALL. Children with positive allergy histories reported significantly more infections than those with negative histories; however, effect modification of the infection-ALL associations by child allergy history was not observed. Nonetheless, these observations suggest the importance of assessing both allergy and infectious histories and their possible interactions when evaluating the association between these immune factors and childhood ALL.
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Affiliation(s)
- Paula F Rosenbaum
- Center for Outcomes Research and Evaluation, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
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47
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Canfield KN, Spector LG, Robison LL, Lazovich D, Roesler M, Olshan AF, Smith FO, Heerema NA, Barnard DR, Blair CK, Ross JA. Childhood and maternal infections and risk of acute leukaemia in children with Down syndrome: a report from the Children's Oncology Group. Br J Cancer 2005; 91:1866-72. [PMID: 15520821 PMCID: PMC2409774 DOI: 10.1038/sj.bjc.6602223] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Children with Down syndrome (DS) are highly susceptible to acute leukaemia. Given the potential role of infections in the aetiology of leukaemia in children without DS, we investigated whether there was an association between early-life infections and acute leukaemia in children with DS. Maternal infections during pregnancy were also examined. We enrolled 158 incident cases of acute leukaemia in children with DS (97 acute lymphoblastic leukaemia (ALL) and 61 acute myeloid leukaemia (AML)) diagnosed at Children's Oncology Group institutions between 1997 and 2002. DS controls (N=173) were selected from the cases' primary care clinics and frequency matched on age at leukaemia diagnosis. Data were collected on demographics, child's medical history, mother's medical history, and other factors by maternal interview. Analyses were conducted using unconditional logistic regression adjusted for potential confounders. A significant negative association was observed between acute leukaemia and any infection in the first 2 years of life (adjusted odds ratio (OR)=0.55, 95% confidence interval (CI) (0.33–0.92); OR=0.53, 95% CI (0.29–0.97); and OR=0.59, 95% CI (0.28–1.25) for acute leukaemia combined, ALL, and AML respectively). The association between acute leukaemia and maternal infections during pregnancy was in the same direction but not significant. This study offers support for the hypothesis that early-life infections may play a protective role in the aetiology of acute leukaemia in children with DS.
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Affiliation(s)
- K N Canfield
- Division of Epidemiology, University of Minnesota School of Public Health, Minneapolis, MN 55454, USA
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - L G Spector
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- University of Minnesota Cancer Center, USA
| | - L L Robison
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- University of Minnesota Cancer Center, USA
| | - D Lazovich
- Division of Epidemiology, University of Minnesota School of Public Health, Minneapolis, MN 55454, USA
- University of Minnesota Cancer Center, USA
| | - M Roesler
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- University of Minnesota Cancer Center, USA
| | - A F Olshan
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - F O Smith
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - N A Heerema
- Department of Pathology, The Ohio State University, Columbus, OH 43210, USA
| | | | - C K Blair
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- University of Minnesota Cancer Center, USA
| | - J A Ross
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- University of Minnesota Cancer Center, USA
- Department of Pediatrics, Division of Epidemiology and Clinical Research, University of Minnesota, MMC 422, 420 Delaware St SE, Minneapolis, MN 55455, USA. E-mail:
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48
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Roman E, Simpson J, Ansell P, Lightfoot T, Mitchell C, Eden TOB. Perinatal and reproductive factors: a report on haematological malignancies from the UKCCS. Eur J Cancer 2005; 41:749-59. [PMID: 15763652 DOI: 10.1016/j.ejca.2004.11.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Revised: 10/18/2004] [Accepted: 11/11/2004] [Indexed: 10/26/2022]
Abstract
The United Kingdom Childhood Cancer Study was designed to examine the potential aetiological role of a range of perinatal and reproductive factors. Our use of clinical records permitted a more exact characterisation of reproductive events than is possible in investigations that rely on self-reporting; and the increased specificity with which antecedent events were measured produced more precise risk estimates, albeit ones based on progressively smaller numbers. Information on the conduct of this component of the study and results for 1485 children with haematological malignancies and 4864 controls are presented. The 'find' rate for obstetric records was high at 86% for cases, with 81% having information on both matched controls. Associations were seen for severe hyperemesis (Odds Ratio=3.6, 95%Confidence Interval=1.3-10.1, for all leukaemias), polyhydramnios (OR=4.0, 95%CI=1.5-10.3, for acute myeloid leukaemia (AML)), anaemia (haemoglobin <10 g, OR=2.6, 95%CI=1.7-4.1, for AML), and pre-eclampsia (OR=1.7, 95%CI=1.1-2.7, for non-Hodgkin's lymphoma). Babies who developed leukaemia were heavier at birth (>4000 g, OR=1.2, 95%CI=1.0-1.4), as were their older siblings (>4000 g, OR=1.4, 95%1.0-1.9). Mothers' whose children developed common B-cell precursor acute lymphoblastic leukaemia (ALL) were more likely to have had a previous molar pregnancy (OR=5.2, 95%CI=1.9-14.7). Gender-specific analysis revealed that findings often differed markedly for boys and girls; and, in common with other reports, strong associations with Down's syndrome were seen for both ALL and AML.
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Affiliation(s)
- E Roman
- Leukaemia Research Fund Epidemiology and Genetics Unit, Department of Health Sciences, University of York, YO10 5DD, UK.
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49
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Abstract
Studies suggest nearly a 20-fold increased risk of leukemia in individuals with Down syndrome. Most of this increased risk appears in the first few decades of life, with the highest incidence in children less than 5 years of age. It is unknown why children with Down syndrome are at such an increased risk of leukemia. With respect to environmental exposures, it will be important to investigate risk factors associated with childhood leukemia in general (including diagnostic x-rays, pesticides, and other occupational exposures) as well as experiences common to children with Down syndrome (including routine medical screening tests, increased susceptibility to infections, and increased vitamin deficiencies).
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Affiliation(s)
- Julie A Ross
- Division of Pediatric Epidemiology and Clinical Research, Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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zur Hausen H, de Villiers EM. Virus target cell conditioning model to explain some epidemiologic characteristics of childhood leukemias and lymphomas. Int J Cancer 2005; 115:1-5. [PMID: 15688417 DOI: 10.1002/ijc.20905] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Frequent infections in early childhood, whole-day care and a socially unprivileged environment have been reported as protective factors for childhood leukemias and lymphomas. Conversely, a protected social environment, higher level of education and growing up in families with a low number of children are considered as risk factors. Additional risk factors involve agricultural occupation of the parents and exposure to several other occupational factors. These data led to a number of hypotheses that attempted to explain the epidemiologic observations; however, a number of questions are still open. Here we propose a new concept that could explain most of the epidemiologic characteristics. This concept is based on the assumption that persistent infections with TT virus-like agents increase the risk for specific chromosomal translocations. This risk should correlate with the viral load. Interferon induction by intermittent infections should reduce the viral load and thus decrease the risk for chromosomal modifications. Some virologic observations in support of this model are presented.
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Affiliation(s)
- Harald zur Hausen
- Deutsche Krebsforschungszentrum, Angewandte Tumorvirologie, Heidelberg, Germany.
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