Early Life Factors and Polycystic Ovary Syndrome in a Swedish Birth Cohort

Polycystic ovary syndrome (PCOS) is a medical condition with important consequences for women's well-being and reproductive outcomes. Although the etiology of PCOS is not fully understood, there is increasing evidence of both genetic and environmental determinants, including development in early life. We studied a population of 977,637 singleton women born in in Sweden between 1973 and 1995, followed sometime between the age 15 and 40. The incidence of PCOS was measured using hospital register data during 2001-2012, complemented with information about the women's, parents' and sisters' health and social characteristics from population and health care registers. Cox regression was used to study how PCOS is associated with intergenerational factors, and a range of early life characteristics. 11,594 women in the study sample were diagnosed with PCOS during the follow-up period. The hazard rate for PCOS was increased 3-fold (HR 2.98, 95% CI 2.43-3.64) if the index woman's mother had been diagnosed with PCOS, and with 1.5-fold (HR 1.51, 95% CI 1.39-1.63) if their mother had diabetes mellitus. We found associations of PCOS with lower (<7) one-minute Apgar score (HR 1.19, 95% CI 1.09-1.29) and with post-term birth (HR 1.19, 95% CI 1.13-1.26). Furthermore, heavy (10+ cigarettes/day) maternal smoking (HR 1.30, 95% CI 1.18-1.44) and maternal obesity (HR 1.90, 95% CI 1.62-2.36) were strongly associated with PCOS. This study finds support for the heritability and fetal origins of PCOS. Risk of PCOS could be reduced by further emphasizing the importance of maternal and early life health.

Variations in the association of height with mortality, cardiovascular disease and cancer in low-, middle- and high-income countries

BACKGROUND

Final adult height is a useful proxy measure of childhood nutrition and disease burden. Tall stature has been previously associated with decreased risk of all-cause mortality, decreased risk of major cardiovascular events and an increased risk of cancer. However, these associations have primarily been derived from people of European and East Asian backgrounds, and there are sparse data from other regions of the world.

METHODS

The Prospective Urban-Rural Epidemiology study is a large, longitudinal population study done in 21 countries of varying incomes and sociocultural settings. We enrolled an unbiased sample of households, which were eligible if at least one household member was aged 35-70 years. Height was measured in a standardized manner, without shoes, to the nearest 0.1 cm. During a median follow-up of 10.1 years (interquartile range 8.3-12.0), we assessed the risk of all-cause mortality, major cardiovascular events and cancer.

RESULTS

A total of 154 610 participants, enrolled since January 2003, with known height and vital status, were included in this analysis. Follow-up event data until March 2021 were used; 11 487 (7.4%) participants died, whereas 9291 (6.0%) participants had a major cardiovascular event and 5873 (3.8%) participants had a new diagnosis of cancer. After adjustment, taller individuals had lower hazards of all-cause mortality [hazard ratio (HR) per 10-cm increase in height 0.93, 95% confidence interval (CI) 0.90-0.96] and major cardiovascular events (HR 0.97, 95% CI 0.94-1.00), whereas the hazard of cancer was higher in taller participants (HR 1.23, 95% CI 1.18-1.28). The interaction p-values between height and country-income level for all three outcomes were <0.001, suggesting that the association with height varied by country-income level for these outcomes. In low-income countries, height was inversely associated with all-cause mortality (HR 0.88, 95% CI 0.84-0.92) and major cardiovascular events (HR 0.87, 95% CI 0.82-0.93). There was no association of height with these outcomes in middle- and high-income countries. The respective HRs for cancer in low-, middle- and high-income countries were 1.14 (95% CI 0.99-1.32), 1.12 (95% CI 1.04-1.22) and 1.20 (95% CI 1.14-1.26).

CONCLUSIONS

Unlike high- and middle-income countries, tall stature has a strong inverse association with all-cause mortality and major cardiovascular events in low-income countries. Improved childhood physical development and advances in population-wide cardiovascular treatments in high- and middle-income countries may contribute to this gap. From a life-course perspective, we hypothesize that optimizing maternal and child health in low-income countries may improve rates of premature mortality and cardiovascular events in these countries, at a population level.

Telomere length is associated with growth in children in rural Bangladesh

Background:

Previously, we demonstrated that a water, sanitation, handwashing, and nutritional intervention improved linear growth and was unexpectedly associated with shortened childhood telomere length (TL) (Lin et al., 2017). Here, we assessed the association between TL and growth.

Methods:

We measured relative TL in whole blood from 713 children. We reported differences between the 10th percentile and 90th percentile of TL or change in TL distribution using generalized additive models, adjusted for potential confounders.

Results:

In cross-sectional analyses, long TL was associated with a higher length-for-age Z score at age 1 year (0.23 SD adjusted difference in length-for-age Z score [95% CI 0.05, 0.42; FDR-corrected p-value = 0.01]). TL was not associated with other outcomes.

Conclusions:

Consistent with the metabolic telomere attrition hypothesis, our previous trial findings support an adaptive role for telomere attrition, whereby active TL regulation is employed as a strategy to address ‘emergency states’ with increased energy requirements such as rapid growth during the first year of life. Although short periods of active telomere attrition may be essential to promote growth, this study suggests that a longer overall initial TL setting in the first 2 years of life could signal increased resilience against future telomere erosion events and healthy growth trajectories.

Funding:

Funded by the Bill and Melinda Gates Foundation.

Clinical trial number:

NCT01590095

The Sex Specific Association Between Maternal Gestational Diabetes and Offspring Metabolic Status at 1 Year of Age

Previous studies showed the association between maternal GDM and long-term effects of overweight in offspring. However, the nature of this association in the early postnatal period is still undetermined. The aim of this prospective cohort study was to evaluate whether maternal GDM is associated with overweight and obesity status in offspring at age 1 year. We studied 1167 infants born at a large obstetrical care hospital including 778 normal glucose tolerance (NGT) and 389 GDM pregnancies, matched in a 1:2 ratio according to offspring's gender, during the years 2016-2017. Overweight and obesity status in offspring of both groups were evaluated at 1 year of age through questionnaires. Infant outcomes were defined according to the WHO Child Growth Standards based on the length-based BMI-for-age. Female offspring from the GDM group exhibited a higher mean BMI (17.2 vs. 16.6, p < 0.01), a higher rate of obesity (13.9% vs. 7.7%; p < 0.05), and overweight (33.1% vs. 23.5%; p < 0.05) as compared to the NGT female group. In the multivariable regression model, maternal GDM was found to be independently and significantly associated with overweight or obesity in 1-year aged female offspring only (OR 1.61, 95% CI 1.09-2.37, p < 0.05). We found a sex specific association between maternal GDM and the overweight risk only in female offspring at 1 year of age.

Social and physical environments early in development predict DNA methylation of inflammatory genes in young adulthood

Chronic inflammation contributes to a wide range of human diseases, and environments in infancy and childhood are important determinants of inflammatory phenotypes. The underlying biological mechanisms connecting early environments with the regulation of inflammation in adulthood are not known, but epigenetic processes are plausible candidates. We tested the hypothesis that patterns of DNA methylation (DNAm) in inflammatory genes in young adulthood would be predicted by early life nutritional, microbial, and psychosocial exposures previously associated with levels of inflammation. Data come from a population-based longitudinal birth cohort study in metropolitan Cebu, the Philippines, and DNAm was characterized in whole blood samples from 494 participants (age 20-22 y). Analyses focused on probes in 114 target genes involved in the regulation of inflammation, and we identified 10 sites across nine genes where the level of DNAm was significantly predicted by the following variables: household socioeconomic status in childhood, extended absence of a parent in childhood, exposure to animal feces in infancy, birth in the dry season, or duration of exclusive breastfeeding. To evaluate the biological significance of these sites, we tested for associations with a panel of inflammatory biomarkers measured in plasma obtained at the same age as DNAm assessment. Three sites predicted elevated inflammation, and one site predicted lower inflammation, consistent with the interpretation that levels of DNAm at these sites are functionally relevant. This pattern of results points toward DNAm as a potentially important biological mechanism through which developmental environments shape inflammatory phenotypes across the life course.