Number of siblings and the risk of solid tumours: a nation-wide study

Interactions of Consanguinity and Number of Siblings with Childhood Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a common malignancy in children. Consanguinity has a high prevalence in developing countries and increases the probability of homozygosity for many genes which may affect ALL and its prognosis. We conducted a study to explore the impact of consanguinity and number of siblings on ALL as there are currently no studies to describe this effect. Data were collected from patients' records from the Children's University Hospital of Damascus University, which is the major cancer centre for children in Syria. This study included 193 children with ALL over one year. Number of siblings was not with the French-American-British (FAB) classification, gender, ALL subtype, or risk of ALL children. When comparing consanguinity degrees and complete blood counts at diagnosis, significant contradicting data were found in the third-degree and fourth-degree consanguinity when compared to one another and to not having consanguineous parents as third degree consanguinity was associated with normal platelets but lower WBC counts, and fourth-degree consanguinity was associated with normal haemoglobin levels and WBC counts, but lower platelet counts. Having consanguineous parents was also associated with acquiring ALL at an older age, L2 FAB classification, having a positive family history for malignancies, and not having hepatosplenomegaly (P < 0.05). Although L2 is known to be a poor prognosis indicatory, no association was found with consanguinity and risk. Finally, no association was found with ALL subtype or risk (P > 0.05). Although consanguinity and number of siblings have affected some variables and prognostic features of childhood ALL, the aetiology is not clear and we need further studies to clarify such an association as this will help in optimising therapy and accurately determine the risk.

Familial testicular germ cell tumors in two brothers

INTRODUCTION

Two percent of testicular germ cell tumors occur in family clusters. Here, we report metachronous testicular germ cell tumors in two brothers.

CASE PRESENTATION

An elder brother was diagnosed at the age of 30 years old and the pathological diagnosis was mixed testicular germ cell tumor. A tumor in the younger brother was suspected during testicular self-examination. It was confirmed by ultrasound examination at the age of 30 years old, 3 years and 6 months after the diagnosis of the testicular tumor in elder brother. The pathological diagnosis was pure seminoma. Both brothers had stage 1 testicular germ cell tumors and no recurrence was observed during the follow-up period of 4 years and 4 months and 10 months, respectively.

CONCLUSION

Various histological types of tumor can occur in members of one family. Besides genetic predisposition, shared diet, environmental exposure and other factors can contribute to the familial testicular cancer. Testicular self-examination is recommended for family members of a person with testicular germ cell tumor.

Impact of maternal reproductive factors on cancer risks of offspring: A systematic review and meta-analysis of cohort studies

Background

A number of studies have reported on associations between reproductive factors, such as delivery methods, number of birth and breastfeeding, and incidence of cancer in children, but systematic reviews addressing this issue to date have important limitations, and no reviews have addressed the impact of reproductive factors on cancer over the full life course of offspring.

Methods

We performed a comprehensive search in MEDLINE, and Embase up to January 2020 and Web of Science up to 2018 July, including cohort studies reporting the association between maternal reproductive factors of age at birth, birth order, number of births, delivery methods, and breastfeeding duration and cancer in children. Teams of two reviewers independently extracted data and assessed risk of bias. We conducted random effects meta-analyses to estimate summary relative estimates, calculated absolute differences between those with and without risk factors, and used the GRADE approach to evaluate the certainty of evidence.

Results

For most exposures and most cancers, we found no suggestion of a causal relation. We found low to very low certainty evidence of the following very small possible impact: higher maternal age at birth with adult multiple myeloma and lifetime uterine cervix cancer incidence; lower maternal age at birth with childhood overall cancer mortality (RR = 1.15, 95% CI = 1.01–1.30; AR/10,000 = 1, 95% CI = 0 to 2), adult leukemia and lifetime uterine cervix cancer incidence; higher birth order with adult melanoma, cervix uteri, corpus uteri, thyroid cancer incidence, lifetime lung, corpus uteri, prostate, testis, sarcoma, thyroid cancer incidence; larger number of birth with childhood brain (RR = 1.27, 95% CI = 1.06–1.52; AR/10,000 = 1, 95% CI = 0 to 2), leukemia (RR = 2.11, 95% CI = 1.62–2.75; AR/10,000 = 9, 95% CI = 5 to 14), lymphoma (RR = 4.66, 95% CI = 1.40–15.57; AR/10,000 = 11, 95% CI = 1 to 44) incidence, adult stomach, corpus uteri cancer incidence and lung cancer mortality, lifetime stomach, lung, uterine cervix, uterine corpus, multiple myeloma, testis cancer incidence; Caesarean delivery with childhood kidney cancer incidence (RR = 1.25, 95% CI = 1.01–1.55; AR/10,000 = 0, 95% CI = 0 to 1); and breastfeeding with adult colorectal cancer incidence.

Conclusion

Very small impacts existed between a number of reproductive factors and cancer incidence and mortality in children and the certainty of evidence was low to very low primarily due to observational design.

Sociodemographic and Lifestyle Factors in Relation to Gastric Cancer in a High-Risk Region of China: A Matched Case-Control Study

Objectives: To explore the role of sociodemographic and lifestyle factors in the development of gastric cancer in a high-risk region of China.Methods: In a case-control study, all newly diagnosed patients with gastric cancer were compared with healthy controls matched (1:1) by sex, age (±3 years), and place of residence during 2013-2017.Results: A total of 622 gastric cancer and 622 healthy controls were included. Larger household size (>4 family members) appeared to decrease gastric cancer risk for Helicobacter pylori-negative ones (odd ratio = 0.43, 95% CI = 0.26-0.70). Similarly, longer refrigerator ownership was associated with a 67% decreased risk in H. pylori-negative group (95% CI = 0.15-0.77). Participants with a family history of gastric cancer had nearly fivefold higher risk (odd ratio = 4.88, 95% CI = 2.49-9.55). Smoking attributed to 83% increased risk (odd ratio = 1.83, 95% CI = 1.19-2.80). Tea consumption dramatically decreased risk in whole study population (odd ratio = 0.28, 95% CI = 0.17-0.45).Conclusions: In summary, family history, smoking, H. pylori-related chronic atrophic gastritis, and H. pylori infection were positively associated with gastric cancer. Whereas, tea consumption and refrigerator use negatively associated with gastric cancer and could be promoted to reduce gastric cancer rate in high-risk populations, especially in the developing regions.

Global incidence and mortality of pancreatic diseases: a systematic review, meta-analysis, and meta-regression of population-based cohort studies

BACKGROUND

There is a lack of robust estimates of the worldwide incidence and mortality of acute pancreatitis, chronic pancreatitis, pancreatic cysts, and pancreatic cancer in the general population. Our aim was to quantitate and compare the incidence and mortality of major pancreatic diseases in high-quality population-based cohort studies.

METHODS

Three databases (PubMed, Embase, and Scopus) were searched independently by two reviewers. Data from eligible studies were subject to meta-analysis to obtain global estimates. A number of prespecified subgroup analyses and meta-regression analyses were also done.

FINDINGS

48 population-based cohort studies (35 on pancreatic cancer, ten on acute pancreatitis, three on chronic pancreatitis, and none on pancreatic cysts) were identified, with a total study population of 296 million individuals and 119 000 patients with pancreatic diseases. Global estimates of incidence and mortality were 8·14 cases (95% CI 6·63-9·98) per 100 000 person-years and 6·92 deaths (95% CI 3·72-12·89) per 100 000 person-years for pancreatic cancer, 33·74 cases (95% CI 23·33-48·81) per 100 000 person-years and 1·60 deaths (95% CI 0·85-1·58) per 100 000 person-years for acute pancreatitis, and 9·62 cases (95% CI 7·86-11·78) per 100 000 person-years and 0·09 deaths (95% CI 0·02-0·47) per 100 000 person-years for chronic pancreatitis. Subgroup analysis based on the WHO regions showed that the incidences of both pancreatic cancer and acute pancreatitis, and mortality from pancreatic cancer, were significantly higher in the American region than in the European and Western Pacific regions, while the incidence of chronic pancreatitis was significantly higher in the European region than in the American region. Mortality from pancreatic cancer was lowest in the Southeast Asian region. The incidence of chronic pancreatitis was twice as high in men as in women, although there was no difference between sexes for pancreatic cancer or acute pancreatitis.

INTERPRETATION

Globally, acute pancreatitis is the most common pancreatic disease whilst pancreatic cancer is the most lethal. However, their burden is not equal across the globe. The epidemiological estimates reported in this study could inform future high-quality studies.

FUNDING

None.

Birth Order and Mortality: A Population-Based Cohort Study

This study uses Swedish population register data to investigate the relationship between birth order and mortality at ages 30 to 69 for Swedish cohorts born between 1938 and 1960, using a within-family comparison. The main analyses are conducted with discrete-time survival analysis using a within-family comparison, and the estimates are adjusted for age, mother’s age at the time of birth, and cohort. Focusing on sibships ranging in size from two to six, we find that mortality risk in adulthood increases with later birth order. The results show that the relative effect of birth order is greater among women than among men. This pattern is consistent for all the major causes of death but is particularly pronounced for mortality attributable to cancers of the respiratory system and to external causes. Further analyses in which we adjust for adult socioeconomic status and adult educational attainment suggest that social pathways only mediate the relationship between birth order and mortality risk in adulthood to a limited degree.

Risk factors for esophageal and gastric cancers in Shanxi Province, China: a case-control study

OBJECTIVE

Smoking and alcohol consumption explain little of the risk for upper-gastrointestinal (UGI) cancer in China, where over half of all cases in the world occur.

METHODS

We evaluated questionnaire-based risk factors for UGI cancers in a case-control study from Shanxi Province, China, including 600 esophageal squamous cell carcinomas (ESCCs), 599 gastric cardia adenocarcinomas (GCAs), 316 gastric noncardia adenocarcinomas (GNCAs), and 1514 age- and gender-matched controls.

RESULTS

Ever smoking and ever use of any alcohol were not associated with risk of UGI cancer; only modest associations were observed between ESCC risk and highest cumulative smoking exposure, as well as GNCA risk and beer drinking. While several associations were noted for socioeconomic and some dietary variables with one or two UGI cancers, the strongest and most consistent relations for all three individual UGI cancers were observed for consumption of scalding hot foods (risk increased 150-219% for daily vs. never users) and fresh vegetables and fruits (risk decreased 48-70% for vegetables and 46-68% for fruits, respectively, for high vs. low quartiles).

CONCLUSION

This study confirms the minor role of tobacco and alcohol in UGI cancers in this region, and highlights thermal damage as a leading etiologic factor.

Influence of family size and birth order on risk of cancer: a population-based study

BACKGROUND

Family size and birth order are known to influence the risk of some cancers. However, it is still unknown whether these effects change from early to later adulthood. We used the data of the Swedish Family-Cancer Database to further analyze these effects.

METHODS

We selected over 5.7 million offspring with identified parents but no parental cancer. We estimated the effect of birth order and family size by Poisson regression adjusted for age, sex, period, region and socioeconomic status. We divided the age at diagnosis in two groups, below and over 50 years, to identify the effect of family size and birth order for different age periods.

RESULTS

Negative associations for increasing birth order were found for endometrial, testicular, skin, thyroid and connective tissue cancers and melanoma. In contrast, we observed positive association between birth order and lung, male and female genital cancers. Family size was associated with decreasing risk for endometrial and testicular cancers, melanoma and squamous cell carcinoma; risk was increased for leukemia and nervous system cancer. The effect of birth order decreased for lung and endometrial cancer from age at diagnosis below to over 50 years. Combined effects for birth order and family size were marginally significant for thyroid gland tumors. Especially, the relative risk for follicular thyroid gland tumors was significantly decreased for increasing birth order.

CONCLUSION

Our findings suggest that the effect of birth order decreases from early to late adulthood for lung and endometrial cancer.

Birth order and risk of non-hodgkin lymphoma--true association or bias?

There is inconsistent evidence that increasing birth order may be associated with risk of non-Hodgkin lymphoma (NHL). The authors examined the association between birth order and related variables and NHL risk in a pooled analysis (1983-2005) of 13,535 cases and 16,427 controls from 18 case-control studies within the International Lymphoma Epidemiology Consortium (InterLymph). Overall, the authors found no significant association between increasing birth order and risk of NHL (P-trend = 0.082) and significant heterogeneity. However, a significant association was present for a number of B- and T-cell NHL subtypes. There was considerable variation in the study-specific risks which was partly explained by study design and participant characteristics. In particular, a significant positive association was present in population-based studies, which had lower response rates in cases and controls, but not in hospital-based studies. A significant positive association was present in higher-socioeconomic-status (SES) participants only. Results were very similar for the related variable of sibship size. The known correlation of high birth order with low SES suggests that selection bias related to SES may be responsible for the association between birth order and NHL.

The association between birth order, sibship size and glioma development in adulthood

The etiology of brain tumors is still largely unknown. Previous research indicates that infectious agents and immunological characteristics may influence adult glioma risk. The purpose of our study was to evaluate the effects of birth order and sibship size (total number of siblings), as indicators of the timing and frequency of early life infections, on adult glioma risk using a population of 489 cases and 540 cancer-free controls from the Harris County Brain Tumor Study. Odds ratios for birth order and sibship size were calculated separately from multivariable logistic regression models, adjusting for sex, family history of cancer, education, and age. Each one-unit increase in birth order confers a 13% decreased risk of glioma development in adulthood (OR = 0.87, 95% CI = 0.79-0.97). However, sibship size was not significantly associated with adult glioma status (OR = 0.97, 95% CI = 0.91-1.04). Our study indicates that individuals who were more likely to develop common childhood infections at an earlier age (those with a higher birth order) may be more protected against developing glioma in adulthood. More biological and epidemiological research is warranted to clarify the exact mechanisms through which the timing of common childhood infections and the course of early life immune development affect gliomagenesis.

Etiologic factors in testicular germ-cell tumors

Globally, testicular cancer incidence is highest among men of northern European ancestry and lowest among men of Asian and African descent. Incidence rates have been increasing around the world for at least 50 years, but mortality rates, at least in developed countries, have been declining. While reasons for the decreases in mortality are related to improvements in therapeutic regimens introduced in the late 1970s, reasons for the increase in incidence are less well understood. However, an accumulating body of evidence suggests that testicular cancer arises in fetal life. Perinatal factors, including exposure to endocrine-disrupting chemicals, have been suggested to be related to risk.

A systematic review and meta-analysis of perinatal variables in relation to the risk of testicular cancer--experiences of the mother

BACKGROUND

We undertook a systematic review and meta-analysis of perinatal variables in relation to testicular cancer risk, with a specific focus upon characteristics of the mother.

METHODS

EMBASE, PubMed, Scopus and Web of Science databases were searched using sensitive search strategies. Meta-analysis was undertaken using STATA 10.

RESULTS

A total of 5865 references were retrieved, of which 67 met the inclusion criteria and contributed data to at least one perinatal analysis. Random effects meta-analysis found maternal bleeding during pregnancy [odds ratio (OR) 1.33, 95% confidence interval (CI) 1.02-1.73], birth order (primiparous vs not, 1.08, 95% CI 1.01-1.16; second vs first, OR 0.94, 95% CI 0.88-0.99; third vs first, OR 0.91, 95% CI 0.83-1.01; fourth vs first, OR 0.80, 95% CI 0.69-0.94) and sibship size (2 vs 1, OR 0.93, 95% CI 0.75-1.15; 3 vs 1, OR 0.89, 95% CI 0.74-1.07; 4 vs 1, OR 0.75, 95% CI 0.62-0.90) to be associated with testicular cancer risk. Meta-analyses that produced summary estimates which indicated no association included maternal age, maternal nausea, maternal hypertension, pre-eclampsia, breech delivery and caesarean section. Meta-regression provided evidence that continent of study is important in the relationship between caesarean section and testicular cancer (P = 0.035), and a meta-analysis restricted to the three studies from the USA was suggestive of association (OR 1.67, 95% CI 1.07-2.56).

CONCLUSIONS

This systematic review and meta-analysis has found evidence for associations of maternal bleeding, birth order, sibship size and possibly caesarean section with risk of testicular cancer.

Sibship size, Helicobacter pylori infection and chronic atrophic gastritis: a population-based study among 9444 older adults from Germany

BACKGROUND

Early-life social environment has been suggested to play an important role during the development of Helicobacter pylori-related gastric diseases. We aimed to assess the association of sibship size with H. pylori infection and chronic atrophic gastritis (CAG) in a population-based study from Germany.

METHODS

In the baseline examination of ESTHER, a study conducted in Saarland, serological measurements of pepsinogen I and II and H. pylori antibodies were taken in 9444 participants aged 50-74 years. Information on potential risk factors and medical history were obtained by self-administered standardized questionnaire.

RESULTS

A strong dose-response relationship between sibship size and H. pylori seroprevalence was observed (P < 0.01). Adjusted odds ratios (ORs) 95% confidence interval (CI) for H. pylori seropositivity for subjects with 4, 5, 6 and 7 or more siblings compared with subjects without siblings were 1.45 (1.20-1.77), 1.83 (1.50-2.22) and 1.84 (1.47-2.31), respectively. A large sibship size was also associated with an increased risk of CAG with an adjusted OR of 1.42 (1.01-2.01) for 7 or more compared with less than or equal to 2 siblings. This association was attenuated but not entirely eliminated after additional adjustment for H. pylori infection. Notably, a significant association between large sibship size and CAG was also found among H. pylori-negative subjects.

CONCLUSIONS

Our results suggest that large sibship size is associated with increased H. pylori prevalence and CAG risk. The association with CAG risk may be mediated at least in part by H. pylori infection. However, mechanisms other than H. pylori infection may contribute to the 'sibling effect' as well.

Association between number of siblings and cause-specific mortality in the Glasgow alumni cohort study

In the Glasgow University Alumni cohort, students with no siblings experienced higher respiratory disease mortality. This risk diminished after accounting for potential confounders. We did not find strong evidence of an association with all cause, coronary heart disease, stroke or stomach cancer mortality. Number of siblings is a proxy for other exposures and exploring its association with specific disease outcomes can help disentangle some of the pathways relating early life exposures to adult mortality.