Perinatal markers of estrogen exposure and risk of testicular cancer: follow-up of 1,333,873 Danish males born between 1950 and 2002

Collateral Damage: Maternal Obesity During Pregnancy Continues to Rise

Importance

The pandemic of obesity during pregnancy now afflicts 1 out of every 2 pregnant women in the United States. Even though unintended pregnancy has decreased to 45% of all pregnancies, 50% of those unintended pregnancies occur in obese women.

Objective

This study aims to identify why current lifestyle interventions for obese pregnancy are not effective and what the newer complications are for obesity during pregnancy.

Evidence Acquisition

Available literatures on current treatments for maternal obesity were reviewed for effectiveness. Emerging maternal and infant complications from obesity during pregnancy were examined for significance.

Results

Limitations in successful interventions fell into 3 basic categories to include the following: (1) preconception weight loss; (2) bariatric surgery before pregnancy; and (3) prevention of excessive gestational weight gain during pregnancy. Emerging significant physiological changes from maternal obesity is composed of inflammation (placenta and human milk), metabolism (hormones, microbiome, fatty acids), and offspring outcomes (body composition, congenital malformations, chronic kidney disease, asthma, neurodevelopment, and behavior).

Conclusions and Relevance

Are current prepregnancy lifestyle and behavioral interventions feasible to prevent maternal obesity complications? Epigenetic and metabolomic research will be critical to determine what is needed to blunt the effects of maternal obesity and to discover successful treatment.

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.

Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: A systematic review

INTRODUCTION

The digitalization of medicine has led to a considerable growth of heterogeneous health datasets, which could improve healthcare research if integrated into the clinical life cycle. This process requires, amongst other things, the harmonization of these datasets, which is a prerequisite to improve their quality, re-usability and interoperability. However, there is a wide range of factors that either hinder or favor the harmonized collection, sharing and linkage of health data.

OBJECTIVE

This systematic review aims to identify barriers and facilitators to health data harmonization-including data sharing and linkage-by a comparative analysis of studies from Denmark and Switzerland.

METHODS

Publications from PubMed, Web of Science, EMBASE and CINAHL involving cross-institutional or cross-border collection, sharing or linkage of health data from Denmark or Switzerland were searched to identify the reported barriers and facilitators to data harmonization.

RESULTS

Of the 345 projects included, 240 were single-country and 105 were multinational studies. Regarding national projects, a Swiss study reported on average more barriers and facilitators than a Danish study. Barriers and facilitators of a technical nature were most frequently reported.

CONCLUSION

This systematic review gathered evidence from Denmark and Switzerland on barriers and facilitators concerning data harmonization, sharing and linkage. Barriers and facilitators were strictly interrelated with the national context where projects were carried out. Structural changes, such as legislation implemented at the national level, were mirrored in the projects. This underlines the impact of national strategies in the field of health data. Our findings also suggest that more openness and clarity in the reporting of both barriers and facilitators to data harmonization constitute a key element to promote the successful management of new projects using health data and the implementation of proper policies in this field. Our study findings are thus meaningful beyond these two countries.

Early life risk factors for testicular cancer: a case-cohort study based on the Copenhagen School Health Records Register

PURPOSE

One established risk factors for testicular cancer is cryptorchidism. However, it remains unclear whether cryptorchidism is a risk factor in itself or whether the two conditions share common causes in early life (estrogen hypothesis), such as birth weight and birth order. The objective of this study is to utilize data from the Copenhagen School Health Records Register (CSHRR) to evaluate cryptorchidism, birth weight and birth order as risk factors for testicular cancer.

METHODS

The study population consisted of 408 cases of testicular cancer identified by a government issued identification number linkage of the entire CSHRR with the Danish Cancer Registry and a random subsample of 4819 males from the CSHRR. The study design was case-cohort and the period of follow-up between 2 April 1968 and 31 December 2003.

RESULTS

Cryptorchidism was significantly associated with testicular cancer in crude analyses [hazard ratio (HR) = 3.60, 95% CI 2.79-4.65]. Birth weight was inversely associated with testicular cancer and no clear association with birth order was observed. The positive association between cryptorchidism and testicular cancer was only slightly attenuated controlling for birth weight and birth order and stratified on birth cohort (HR = 3.46, 95% CI 2.67-4.48).

CONCLUSION

This study confirmed the robustness of the association between cryptorchidism and testicular cancer even after adjustment for birth weight and birth order. Furthermore, the study showed an inverse association between birth weight and testicular cancer.

Risk of Sex-Specific Cancers in Opposite-Sex and Same-Sex Twins in Denmark and Sweden

BACKGROUND

Increasing evidence shows that some cancers originate in utero. It is hypothesized that elevated exposure to some steroid hormones might increase cancer risk and that hormone transfer between twin fetuses could result in different prenatal exposure to testosterone.

METHODS

This large-scale prospective twin study compared opposite-sex (OS) and same-sex (SS) twins to test the impact of intrauterine exposures on cancer risk. On the basis of the Danish and Swedish twin and cancer registries, we calculated incidence rate ratios for OS and SS twins, whereas standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated for OS/SS twins compared with the general population.

RESULTS

A total of 18,001 cancers were identified during 1943-2009. No significant differences were observed between OS and SS twins, neither for the sex-specific cancers nor for cancer at all sites. All-cause cancer was slightly reduced for OS and SS twins compared with the general population, significant for OS males (SIR, 0.95; 95% CI, 0.92-0.98) and for SS males and females (SIR, 0.97; 95% CI, 0.94-0.99).

CONCLUSIONS

Our data suggest that having a male co-twin-which may entail higher exposure to prenatal testosterone-does not increase the risk of sex-specific cancers in OS females. Furthermore, the study supports that twinning per se is not a risk factor of cancer.

IMPACT

Findings are reassuring, as they fail to provide evidence for the hypothesis that endocrine or other difference in the in utero milieu affects the risk of sex-specific cancers.

Endocrine disruption: fact or urban legend?

Endocrine disruptors (EDs) are substances that cause adverse health effects via endocrine-mediated mechanisms in an intact organism or its progeny or (sub) populations. Purported EDCs in personal care products include 4-MBC (UV filter) or parabens that showed oestrogenic activity in screening tests, although regulatory toxicity studies showed no adverse effects on reproductive endpoints. Hormonal potency is the key issue of the safety of EDCs. Oestrogen-based drugs, e.g. the contraceptive pill or the synthetic oestrogen DES, possess potencies up to 7 orders of magnitude higher than those of PCP ingredients; yet, in utero exposure to these drugs did not adversely affect fertility or sexual organ development of offspring unless exposed to extreme doses. Additive effects of EDs are unlikely due to the multitude of mechanisms how substances may produce a hormone-like activity; even after uptake of different substances with a similar mode of action, the possibility of additive effects is reduced by different absorption, metabolism and kinetics. This is supported by a number of studies on mixtures of chemical EDCs. Overall, despite of 20 years of research a human health risk from exposure to low concentrations of exogenous chemical substances with weak hormone-like activities remains an unproven and unlikely hypothesis.

The maternal womb: a novel target for cancer prevention in the era of the obesity pandemic?

The dramatic rise in worldwide prevalence of obesity has necessitated the search for more efficacious antiobesity strategies to counter the increased cancer risks in overweight and obese individuals. The mechanistic pathways linking obesity status with adult chronic diseases such as cancer remain incompletely understood. A growing body of evidence suggests that novel approaches and interventional agents to disrupt the feed-forward cycle of maternal to offspring obesity transfer that is initiated in utero will be important for stemming both the obesity pandemic and the associated increase in cancer incidence. The convergence of multiple research areas including those encompassing the insulin and insulin-like growth factor systems, epigenetics, and stem cell biology is providing insights into the potential for cancer prevention in adult offspring previously exposed to the intrauterine environment of overweight/obese mothers. Here, we review the current state of this nascent research field, with a focus on three major cancers, namely breast, colorectal, and liver, and suggest some possible future directions to optimize its impact for the health of future generations.

Cryptorchidism and hypospadias in a cohort of 934,538 Danish boys: the role of birth weight, gestational age, body dimensions, and fetal growth

Early delivery and low birth weight are strong predictors of the urogenital anomalies cryptorchidism (undescended testis) and hypospadias. Understanding these associations may lead to important etiologic clues. Therefore, the authors revisited the prevailing hypotheses regarding fetal growth restriction as a risk factor for urogenital anomalies. They studied a population of 934,538 Danish boys born alive between January 1, 1980, and December 31, 2008. Cryptorchidism and hypospadias were associated with low weight-for-gestational-age, an indicator of fetal growth restriction, and furthermore the authors observed strong interaction with early delivery. Low birth weight in a singleton compared with the mean birth weight of all singleton brothers in the family or in a twin compared with the male co-twin was associated with higher risk of urogenital anomalies, suggesting an effect of relative fetal growth restriction within families. Contrary to previous reports, newborns' body dimensions assessed independently of birth weight were not associated with urogenital anomalies. The hypothesis that shared factors cause both fetal growth restriction and urogenital anomalies was supported by comparison of urogenital anomaly risks in singletons and twins and by patterns of cryptorchidism and hypospadias co-occurrence in individuals. These novel insights might also extend to other male reproductive conditions with prenatal etiology.

Gestational age at birth and risk of testicular cancer

Most testicular germ cell tumors originate from carcinoma in situ cells in fetal life, possibly related to sex hormone imbalances in early pregnancy. Previous studies of association between gestational age at birth and testicular cancer have yielded discrepant results and have not examined extreme preterm birth. Our objective was to determine whether low gestational age at birth is independently associated with testicular cancer in later life. We conducted a national cohort study of 354,860 men born in Sweden in 1973-1979, including 19,214 born preterm (gestational age < 37 weeks) of whom 1,279 were born extremely preterm (22-29 weeks), followed for testicular cancer incidence through 2008. A total of 767 testicular cancers (296 seminomas and 471 nonseminomatous germ cell tumors) were identified in 11.2 million person-years of follow-up. Extreme preterm birth was associated with an increased risk of testicular cancer (hazard ratio = 3.95; 95% confidence interval = 1.67-9.34) after adjusting for other perinatal factors, family history of testicular cancer and cryptorchidism. Only five cases (three seminomas and two nonseminomas) occurred among men born extremely preterm, limiting the precision of risk estimates. No association was found between later preterm birth, post-term birth or low or high fetal growth and testicular cancer. These findings suggest that extreme but not later preterm birth may be independently associated with testicular cancer in later life. They are based on a small number of cases and will need confirmation in other large cohorts. Elucidation of the key prenatal etiologic factors may potentially lead to preventive interventions in early life.

Birthweight and mortality in adulthood: a systematic review and meta-analysis

BACKGROUND

Small birth size may be associated with increased risk of cardiovascular diseases (CVD), whereas large birth size may predict increased risk of obesity and some cancers. The net effect of birth size on long-term mortality has only been assessed in individual studies, with conflicting results.

METHODS

The Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines for conducting and reporting meta-analysis of observational studies were followed. We retrieved 22 studies that assessed the association between birthweight and adult mortality from all causes, CVD or cancer. The studies were systematically reviewed and those reporting hazard ratios (HRs) and 95% confidence intervals (95% CIs) per kilogram (kg) increase in birthweight were included in generic inverse variance meta-analyses.

RESULTS

For all-cause mortality, 36,834 deaths were included and the results showed a 6% lower risk (adjusted HR = 0.94, 95% CI: 0.92-0.97) per kg higher birthweight for men and women combined. For cardiovascular mortality, the corresponding inverse association was stronger (HR = 0.88, 95% CI: 0.85-0.91). For cancer mortality, HR per kg higher birthweight was 1.13 (95% CI: 1.07-1.19) for men and 1.04 (95% CI: 0.98-1.10) for women (P(interaction) = 0.03). Residual confounding could not be eliminated, but is unlikely to account for the main findings.

CONCLUSION

These results show an inverse but moderate association of birthweight with adult mortality from all-causes and a stronger inverse association with cardiovascular mortality. For men, higher birthweight was strongly associated with increased risk of cancer deaths. The findings suggest that birthweight can be a useful indicator of processes that influence long-term health.

Maternal body mass index and risk of testicular cancer in male offspring: a systematic review and meta-analysis

OBJECTIVES

To date a number of studies have examined the association between maternal weight and testicular cancer risk although results have been largely inconsistent. This systematic review and meta-analysis investigated the nature of this association.

METHODS

Search strategies were conducted in Ovid Medline (1950-2009), Embase (1980-2009), Web of Science (1970-2009), and CINAHL (1937-2009) using keywords for maternal weight (BMI) and testicular cancer.

RESULTS

The literature search produced 1689 hits from which 63 papers were extracted. Only 7 studies met the pre-defined criteria. Random effects meta-analyses were conducted. The combined unadjusted OR (95% CI) of testicular cancer in the highest reported category of maternal BMI compared with the moderate maternal BMI was 0.82 (0.65-1.02). The Cochran's Q P value was 0.82 and the corresponding I(2) was 0%, both indicating very little variability among studies. The combined unadjusted OR (95% CI) for testicular cancer risk in the lowest reported category of maternal BMI compared to a moderate maternal BMI category was 0.88 (0.65-1.20). The Cochran's Q P value was 0.05 and the corresponding I(2) was 54%, indicating evidence of statistical heterogeneity. The combined unadjusted OR (95% CI) of testicular cancer risk per unit increase in maternal BMI was 1.01 (0.97-1.06). The Cochran's Q test had a P value of 0.05 and the corresponding I(2) was 55% indicating evidence of statistical heterogeneity.

CONCLUSION

This meta-analysis, which included a small number of studies, showed that a higher maternal weight does not increase the risk of testicular cancer in male offspring. Though an inverse association between high maternal BMI and testicular cancer risk was detected, it was not statistically significant. Further primary studies with adjustment for appropriate confounders are required.