Exposure during pregnancy to a specific per- and polyfluoroalkyl substance (PFAS), combined with a low cholesterol level, is linked to a heightened risk of abdominal and whole-body obesity in granddaughters, according to a new analysis of the Child Health and Development Studies, which have been ongoing since the 1960s.
Researchers directly measured levels of N-ethyl-perfluorooctane sulfonamido acetic acid (EtFOSAA) in blood samples from the grandmothers, which had been taken shortly after delivery, and then analyzed measures of obesity and other metabolic factors in their daughters at ages 30 years and 50 years, and their granddaughters at age 20.
PFASs are synthetic compounds commonly used as oil and water repellents; coatings for cookware, carpets, and textiles; and as firefighting foams. The compounds do not break down in the environment or the human body and accumulate over time. They are known to disrupt the endocrine system.
EtFOSAA is a metabolite of a raw material used in the manufacturing of packaging and paper products, and itself gets converted to perfluorooctane sulfonic acid (PFOS), which is extremely stable in the environment and within organisms, leading to bioaccumulation that has the potential to span generations, Barbara A. Cohn, PhD, director of child health and development studies at the Public Health Institute in Berkeley, Calif., said during a virtual press conference held by The Endocrine Society. The study was slated for presentation during ENDO 2020, the society’s annual meeting, which was canceled because of the COVID-19 pandemic.
Abdominal obesity was defined as a waist circumference of more than 34.6 inches (88 cm), and whole-body obesity was defined as a body mass index of more than 30 kg/m2. Findings from a previous study drawn from the same cohort showed that exposure to EtFOSAA, combined with high maternal cholesterol levels, was linked to increased risk of breast cancer in daughters.
“I want to emphasize that we don’t understand the mechanism, but we do know that this finding [from the current study], if it is confirmed, has implications for the current epidemic of obesity. Exposure to these compounds is very widespread, [having] started in the 1940s and 50s, and is consistent with the timing of the obesity epidemic,” said Dr. Cohn, during the virtual press conference.
Dr. Robert Sargis
Robert Sargis, MD, professor of endocrinology, diabetes, and metabolism at the University of Illinois at Chicago, said the mechanistic connection could be complex. “It’s a combination of the possibility that the chemicals themselves are passed down either through breast milk or across the placenta, or that the biological impact is somehow coded epigenetically, and then that epigenetic code is somehow passed on to subsequent generations,” he said in an interview. He was not associated with the research.
Dr. Cohn said her team is investigating both of those possibilities through analysis of the existing blood samples. “There are implications for PFAS clean-up if [these findings are] confirmed, and there’s an opportunity for setting up precautions for pregnant women on how they can try to avoid this contamination to [offset] a rekindling of this generational effect 60 years down the road,” Dr. Cohn added.
Daughters of the original participants (now grandmothers) were measured at an average age of 50, and the granddaughters, at an average of 20 (219 dyads, 657 women in total). Daughters also reported their weight at age 30, which was close to the mean age at which they had given birth. This allowed the researchers to control for obesity present during gestation of the granddaughters.
The researchers analyzed EtFOSAA, PFOS, and cholesterol levels from archived blood samples taken from grandmothers within 3 days of delivery. There was an association between EtFOSAA and self-reported obesity at age 30 in daughters, as well as measured abdominal, whole-body obesity, and blood pressure at age 20 in granddaughters, and all were modified by low cholesterol levels (25% interquartile) in grandmothers (P < .05).
In granddaughters, the combined risk of abdominal and whole-body obesity was 2.3-fold higher in those whose grandmothers were in the top 25% of EtFOSAA exposure, compared with those whose grandmothers were in the lowest 25% (95% confidence interval, 1.1-4.8). Those associations remained after adjustments for race, being overweight in early pregnancy (BMI, >25 kg/m2), and serum PFOS levels.
Although the weight of daughters did not affect the association between the granddaughters’ risk for obesity risk and EtFOSAA levels in grandmothers, it did predict high metabolic risk in granddaughters. That suggests that the burden may be building over generations. “Independently, their mothers themselves are heavier and fatter, and that heaviness of the mother is also a source of increasing body size for the granddaughter. We have a multiplying, very ugly situation that may be helping us to understand this really quick rise of obesity,” said Dr. Cohn.
She also emphasized that PFAS may not be the only culprit in fueling obesity. “Most of us believe that there is sufficient data in the animal studies and, now, growing data in human studies, to suggest that these obesogens exist and are contributing to the health problems that are going to be following the obesity epidemic in young people now.”
Dr. Cohn noted that the study is limited by its lack of a control group.
The California Breast Research Foundation, the National Institutes of Health, and the State of California funded the study. Dr. Cohn and Dr. Sargis reported no relevant financial disclosures.
The study abstract will be published in the Journal of the Endocrine Society. In addition to a series of news conferences held on March 30-31, the society will host ENDO Online 2020 during June 8-22 with programming for clinicians and researchers.
SOURCE: Cohn B et al. ENDO 2020, Abstract LB132.