Paternal occupation and neuroblastoma: a case-control study based on cancer registry data for Great Britain 1962-1999

Agricultural exposures and risk of childhood neuroblastoma: a systematic review and meta-analysis

While neuroblastoma accounts for an estimated 8% of childhood cancers, it causes about 15% of childhood cancer deaths in the United States. The role of agricultural exposures in the development of neuroblastoma is unclear. We conducted a systematic review and meta-analysis of studies examining the relationship between agricultural exposures and neuroblastoma. MEDLINE, EMBASE, Scopus, and Google Scholar were searched in February 2022, identifying 742 publications. Seventeen articles met the inclusion criteria; all were published between 1985 and 2020 and included 14 case-control, one cross-sectional, and two cohort studies. Random and fixed effects models were used to calculate summary odds ratios (sORs) and 95% confidence intervals (CIs). An increased odds of developing neuroblastoma with parental exposure to any pesticides (sOR = 1.25, 95% CI: 1.03-1.48; 4 studies), insecticides (sOR = 1.55, 95% CI: 1.19-1.91; 3 studies), and residential exposure to crops/vegetables (sOR = 1.04, 95% CI: 1.01-1.06; 2 studies) was seen. Heterogeneity was low in all analyses, and no publication bias was evident. No significant associations were found with agricultural occupations, herbicides, and agricultural dusts. The studies were limited by exposure measurements and small sample sizes. Further studies are needed to explore mechanisms in the development of neuroblastoma in children with parental agricultural exposures, especially pesticides, and to improve methods of measuring agricultural-related exposures.

Relationship between parental exposure to radiofrequency electromagnetic fields and primarily hematopoietic neoplasms (lymphoma, leukemia) and tumors in the central nervous system in children: a systematic review

Low-frequency electromagnetic fields have grown exponentially in recent years due to technological development and modernization. The World Health Organization (WHO)/International Agency for Research on Cancer (IARC) has classified radiofrequency electromagnetic fields (RF-EMFs) as possibly carcinogenic to humans (Group 2B), and recent studies have investigated the association between exposure to electromagnetic fields in parents and possible health effects in children, especially the development of tumours of the central nervous system (CNS). The objective of this systematic review was to collate all evidence on the relationship between parental occupational exposure to electromagnetic fields and the development of CNS cancer in children and to evaluate this association. This review was prepared according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Embase, and Web of Science were searched from January 1990 to April 2021. The search was conducted using the following search string: "occupational" AND "child" AND "electromagnetic" AND "cancer". Seventeen articles met our inclusion criteria: 13 case-control studies, two cohort studies, and 2 meta-analyses. Most of the studies showed several methodological weaknesses that limited their results. Due to a lack of consistency regarding the outcome as well as the heterogeneity in the reviewed studies, the body of evidence for the effects of parental exposure to electromagnetic fields is not clear. Methodological heterogeneity in the way that studies were conducted could be responsible for the lack of consistency in the findings. Overall, the body of evidence allows no conclusion on the relationship between parental exposure to electromagnetic fields and the occurrence of CNS tumours in children.

Pre-conceptional and prenatal exposure to pesticides and pediatric neuroblastoma. A meta-analysis of nine studies

Neuroblastoma is primarily an embryonal tumor of infancy. Recently, some toxicological agents used as pesticides have been associated with an increased incidence of this tumor. We intended to determine the potential association between prenatal exposure to pesticides and the incidence of neuroblastoma in children. Studies targeting the link between neuroblastoma and pesticides were searched in PUBMED, SCOPUS, and Google Scholar from January 1, 1960, through December 2020. We performed a PRISMA-based systematic review and meta-analysis. In addition, we took into consideration the IARC evaluation on pesticides issued in recent monographs. Prenatal pesticide exposure is associated with an increased risk of neuroblastoma with an OR of 1.6 (1.1-2.3; p = 0.013), while the OR is 1.0 (0.8-1.3; p = 0.723) for pesticide exposure after birth. There is a significant association between prenatal pesticide exposure and neuroblastoma. We emphasize the IARC conclusions evaluating the carcinogenicity of diazinon, glyphosate, malathion, parathion, and tetrachlorvinphos.

Case-control study of paternal occupational exposures and childhood bone tumours and soft-tissue sarcomas in Great Britain, 1962-2010

BACKGROUND

This nationwide study investigated associations between paternal occupational exposure and childhood bone tumours and soft- tissue sarcomas.

METHODS

The UK National Registry of Childhood Tumours provided cases of childhood sarcomas born and diagnosed in Great Britain, 1962-2010. Control births, unaffected by childhood cancer, were matched on sex, birth period and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups and coded for occupational social class.

RESULTS

We analysed 5,369 childhood sarcoma cases and 5380 controls. Total bone tumours, total soft-tissue sarcomas and the subgroups osteosarcoma, rhabdomyosarcoma and Ewing Sarcoma Family of Tumours (ESFT) were considered separately. Significant positive associations were seen between rhabdomyosarcoma and paternal exposure to EMFs (odds ratio = 1.67, CI = 1.22-2.28) and also for ESFT and textile dust (1.93, 1.01-3.63). There were putative protective effects on total bone tumours of paternal dermal exposure to hydrocarbons, metal, metal working or oil mists.

CONCLUSIONS

Despite the large size and freedom from bias of this study, our results should be interpreted with caution. Many significance tests were undertaken, and chance findings are to be expected. Nevertheless, our finding of associations between ESFT and paternal exposure to textile dust may support related suggestions in the literature.

Parental occupational organic dust exposure and selected childhood cancers in Denmark 1968-2016

BACKGROUND

Parental occupational exposures are suggested as contributing causes of childhood cancer.

METHODS

Children age< = 19, born in Denmark and diagnosed with leukemia, central nervous system (CNS) cancers and likely prenatally initiated cancers [hepatoblastoma, medulloblastoma, Wilms tumor (nephroblastoma), neuroblastoma, retinoblastoma and acute lymphoid leukemia] n = 4268 were identified using Danish registries. We randomly selected twenty-five controls per case matched on birth year and sex. Parents and their employment histories were extracted from nationwide registries. We examined occupational dust exposures perinatally and postnatally in both parents. Odds ratios (ORs) and 95 % confidence intervals (95 % CI) were estimated using conditional logistic regression.

RESULTS

Maternal wood dust exposure from birth to diagnosis was associated with increased risks of leukemia (OR 1.44, 95 % CI 1.08-1.94) and acute myeloid leukemia (OR 2.14, 95 % CI 1.13-4.03); exposure to paper dust was associated with CNS cancer (OR 2.28, 95 % CI 1.22-4.2).. Paternal exposure to wood dust was associated with astrocytoma in both periods (OR 1.43, 95 % CI 1.05-1.96 and 1.42, 1.09-1.86, respectively) and CNS cancer (OR 1.24, 95 % CI 1.00-1.53) in the perinatal period. The increased risk observed for potentially prenatally-initiated cancers in relation to wood was driven by ORs for neuroblastoma (1.54, 95 % CI 1.03-2.29) and hepatoblastoma (2.41, 95 % CI 0.99-5.88). An OR of 2.58 (95 % CI 1.10-6.05) for CNS cancer was associated with both parents working in textile industries postnatally.

CONCLUSION

The study suggests that parental exposure to wood dust may increase risk of specific childhood cancers.

Case-control study of paternal occupational exposures and childhood lymphoma in Great Britain, 1962-2010

BACKGROUND

This nationwide study investigates associations between paternal occupational exposure and childhood lymphoma.

METHODS

The UK National Registry of Childhood Tumours provided cases of childhood lymphoma born and diagnosed in Great Britain 1962-2010. Control births, unaffected by childhood cancer, were matched on sex, birth period and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups and also coded for occupational social class.

RESULTS

We analysed 5033 childhood lymphoma cases and 4990 controls. Total lymphoma and the subgroups Hodgkin, Burkitt and non-Hodgkin lymphoma were considered separately. No one exposure was significantly associated with increased risk within all subgroups and for total lymphoma. However, exposure to "ceramics and glass" was significantly associated with increased risk of total lymphoma, Hodgkin and non-Hodgkin lymphoma. Paternal lead exposure was associated with Burkitt lymphoma and exposure to metal fumes was associated with Hodgkin lymphoma.

CONCLUSIONS

This study provides no support for previous suggestions of an association between childhood lymphoma and paternal occupational exposure to pesticides, solvents/hydrocarbons or infections potentially transmitted by father's social contacts. An association with exposure to "ceramics and glass" was noted for the two major lymphoma subtypes together comprising 80% of total lymphoma.

Association between parental occupational exposure to extremely low frequency magnetic fields and childhood nervous system tumors risk: A meta-analysis

BACKGROUND AND OBJECTIVE

Previous epidemiological studies suggested association between parental occupational exposure to extremely low frequency magnetic fields (ELF-MF) and risk of childhood nervous system tumors, but the results were inconsistent. We conducted a meta-analysis of case-control and cohort studies to re-evaluate this association.

METHODS

Relevant studies were identified by searching PubMed and Web of Science databases as well as by manual searching. Summary odds ratio (OR) with 95% confidence interval (CI) were pooled with a fixed-effects or random-effects model.

RESULTS

A total of 22 eligible articles (21 case-control studies and 1 cohort study) were included for the quantitative analysis. The results showed that parental occupational ELF-MF exposure was significantly associated with an increased risk of childhood nervous system tumors (OR = 1.11, 95% CI = 1.02-1.21), and this association remained in studies on central nervous system (CNS) tumors (OR = 1.13, 95% CI = 1.02-1.27) but not neuroblastoma (OR = 1.02, 95% CI = 0.92-1.14). Furthermore, maternal (OR = 1.14, 95% CI = 1.05-1.23) but not paternal (OR = 1.05, 95% CI = 0.98-1.13) occupational ELF-MF exposure significantly increased risk of childhood nervous system tumors. Increased risk of childhood CNS tumors was significant associated with maternal (OR = 1.16, 95% CI = 1.06-1.26) but not paternal (OR = 1.15, 95% CI = 0.98-1.34) occupational ELF-MF exposure.

CONCLUSION

In conclusion, our results provide limited evidence for the association between maternal occupational exposure to ELF-MF and increased risk of childhood CNS tumors, which should be explained with cautions. Future studies are needed to further evaluate the association of paternal occupational ELF-MF exposure with risk of childhood CNS tumors.

Childhood cancer research in Oxford II: The Childhood Cancer Research Group

BACKGROUND

We summarise the work of the Childhood Cancer Research Group, particularly in relation to the UK National Registry of Childhood Tumours (NRCT).

METHODS

The Group was responsible for setting up and maintaining the NRCT. This registry was based on notifications from regional cancer registries, specialist children's tumour registries, paediatric oncologists and clinical trials organisers. For a large sample of cases, data on controls matched by date and place of birth were also collected.

RESULTS

Significant achievements of the Group include: studies of aetiology and of genetic epidemiology; proposals for, and participation in, international comparative studies of these diseases and on a classification system specifically for childhood cancer; the initial development of, and major contributions to, follow-up studies of the health of long-term survivors; the enhancement of cancer registration records by the addition of clinical data and of birth records. The Group made substantial contributions to the UK government's Committee on Medical Aspects of Radiation in the Environment.

CONCLUSION

An important part of the ethos of the Group was to work in collaboration with many other organisations and individuals, both nationally and internationally: many of the Group's achievements described here were the result of such collaborations.

Cancer incidence and survival among infants in Israel, 1998-2007

Cancer during the first year of life is relatively rare and often has clinical and biological properties different from those of the same histologic type of cancer occurring in older children. The aim of this study was to find differences in epidemiology and survival between infants and older children and to compare the percentage of distribution of infant cancer types in Israel with that reported in the United States. We collected infant <1 year of age cases diagnosed between 1998 and 2007 as having cancer from the database of the Israel National Cancer Registry, a total of 309 cases with an incidence rate of 228.5 cases per million. The largest group was diagnosed with neuroblastoma (35%) with an incident rate of 80 per million, followed by leukemia (15.9%), with acute lymphoid leukemia and acute myeloid leukemia accounting for most of this group and central nervous system malignancies comprised 10.7% of infant cancer. One hundred and fifty four new cases of infant girls was diagnosed compared to 155 infant boys with an incidence rates of 234 cases per million for girls and 224.7 for boys, not statistically significant (F:M rate ratio of 1.04). The 5-year survival rates seen in the different groups were leukemia: 55.3%, lymphoma: 71%, CNS tumors: 53.3%, neuroblastoma: 93.4%, retinoblastoma: 94.7% renal tumors: 90.9%, hepatic tumors: 63.3%, soft tissue sarcoma: 76.2%, germ cell neoplasms: 83.3%, and other epithelial neoplasms: 100%. Our study did not find survival differences with statistical significance upon comparing survival rates between different genders and ethnic groups.

The statistical power of epidemiological studies analyzing the relationship between exposure to ionizing radiation and cancer, with special reference to childhood leukemia and natural background radiation

The etiology of childhood leukemia remains generally unknown, although risk models based on the Japanese A-bomb survivors imply that the dose accumulated from protracted exposure to low-level natural background ionizing radiation materially raises the risk of leukemia in children. In this paper a novel Monte Carlo score-test methodology is used to assess the statistical power of cohort, ecological and case-control study designs, using the linear low-dose part of the BEIR V model derived from the Japanese data. With 10 (or 20) years of follow-up of childhood leukemias in Great Britain, giving about 4600 (or 9200) cases, under an individual-based cohort design there is 67.9% (or 90.9%) chance of detecting an excess (at 5% significance level, one-sided test); little difference is made by extreme heterogeneity in risk. For an ecological design these figures reduce to 57.9% (or 83.2%). Case-control studies with five controls per case achieve much of the power of a cohort design, 61.1% (or 86.0%). However, participation bias may seriously affect studies that require individual consent, and area-based studies are subject to severe interpretational problems. For this reason register-based studies, in particular those that make use of predicted doses that avoid the need for interviews, have considerable advantages. We argue that previous studies have been underpowered (all have power <80%), and some are also subject to unquantifiable biases and confounding. Sufficiently large studies should be capable of detecting the predicted risk attributable to natural background radiation.