Maternal exposure to airborne polychlorinated biphenyls (PCBs) and risk of adverse birth outcomes

Human health effects of airborne lower-chlorinated polychlorinated biphenyls (LC-PCBs) are largely unexplored. Since PCBs may cross the placenta, maternal exposure could potentially have negative consequences for fetal development. We aimed to determine if exposure to airborne PCB during pregnancy was associated with adverse birth outcomes. In this cohort study, exposed women had lived in PCB contaminated apartments at least one year during the 3.6 years before conception or the entire first trimester of pregnancy. The women and their children were followed for birth outcomes in Danish health registers. Logistic regression was performed to estimate odds ratios (OR) for changes in secondary sex ratio, preterm birth, major congenital malformations, cryptorchidism, and being born small for gestational age. We performed linear regression to estimate difference in birth weight among children of exposed and unexposed mothers. All models were adjusted for maternal age, educational level, ethnicity, and calendar time. We identified 885 exposed pregnancies and 3327 unexposed pregnancies. Relative to unexposed women, exposed women had OR 0.97 (95% CI 0.82, 1.15) for secondary sex ratio, OR 1.13 (95% CI 0.76, 1.67) for preterm birth, OR 1.28 (95% CI 0.81, 2.01) for having a child with major malformations, OR 1.73 (95% CI 1.01, 2.95) for cryptorchidism and OR 1.23 (95% CI 0.88, 1.72) for giving birth to a child born small for gestational age. The difference in birth weight for children of exposed compared to unexposed women was − 32 g (95% CI—79, 14). We observed an increased risk of cryptorchidism among boys after maternal airborne LC-PCB exposure, but due to the proxy measure of exposure, inability to perform dose–response analyses, and the lack of comparable literature, larger cohort studies with direct measures of exposure are needed to investigate the safety of airborne LC-PCB exposure during pregnancy

The Effect of Consanguinity on Reproductive Fitness and Selection Intensity in the Muslim Population of Western Uttar Pradesh, India

ABSTRACT The study sought to ascertain the adverse effects of consanguinity among Muslim parents of Aligarh city located in western Uttar Pradesh in India. More than 478 families were visited and data were collected from only 100 of them being inbred to varying degrees of consanguinity. It was found that increasing degree of consanguinity decreases fertility (R2 = 0.2671, r = -0.1568), but increases mortality (R2 = 0.3161, r = 0.5622). Selection intensity (R2 = 0.1734, r = 0.4164) and secondary sex ratio (R2 = 0.3757, r = 0.6129) also go up as the degree of consanguinity increases. However, the genomic basis of Runs of Homozygosity (ROH) is a more accurate method of calculating homozygosity. Next Generation Sequencing may help better understand ROH and their utility as a tool for inbreeding detection. To avoid the inbreeding load, there is a need to raise public awareness of reproductive health and the potential negative effects of consanguinity.