Forever Chemicals: Forever Health Problems?

By Mingyu Zhang, PhD, MHS
Imagine living in a city with strict environmental regulations. Then one day, the authorities announce that the city must switch to an alternative water source. Why? Because the current water supply has been contaminated – it’s no longer safe for drinking, cooking, or bathing. Suddenly, you and your family are living in fear of an invisible enemy that you cannot see, taste, or smell.

This is not a hypothetical scenario. It happened in Cambridge, MA in August 2022 when elevated levels of per- and polyfluoroalkyl substances (PFAS) were found in the drinking water. PFAS are chemicals used in a wide range of products, including food packaging, non-stick cookware, carpets, and waterproof clothing. Known as “forever chemicals”, PFAS are extremely stable and resist degradation. While this stability is beneficial for creating products that resist water, grease, and stains, it also means that PFAS can accumulate in the environment and our bodies, leading to widespread exposure.

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In a recent study published in Environmental Health Perspectives, researchers studied 545 mother-child pairs from the Project Viva cohort in Boston, Massachusetts. They analyzed six types of PFAS chemicals in mothers’ blood samples collected during pregnancy and assessed their children’s adiposity and body composition measures in late adolescence, at ages 16-20.

The findings are concerning. The study revealed that higher levels of maternal PFAS may increase the probability of obesity in late adolescence. Specifically, each doubling of PFOS, PFOA, and PFNA levels (three types of PFAS chemicals) was linked to a 59%, 24%, and 49% higher chance of obesity in late adolescence, respectively, even after accounting for other maternal and child factors. Additionally, the mixture of PFAS compounds had a cumulative effect, further increasing the chance of obesity and raising body mass index (BMI) in adolescents.

One intriguing aspect of the study was the “trajectory analysis” of BMI measures from birth to late adolescence. Project Viva has followed children for over 25 years, collecting BMI data from birth through adolescence. Researchers discovered that children with higher prenatal PFAS exposures experienced more rapid BMI increases starting around ages 9-11, coinciding with puberty onset. This suggests that PFAS may affect children’s weight and body composition by impacting puberty.

These findings highlight the potential long-term health impacts of prenatal PFAS exposures and underscore the need for stricter regulations and better monitoring. Known as “forever chemicals” due to their persistence in the environment “forever,” the health effects of PFAS may also be “forever”, with exposures occurring in the womb and outcomes observed 16-20 years later. As childhood and adolescent obesity rates continue to rise in the US, understanding and mitigating contributing factors is critical.

The Cambridge story has a positive outcome: three months later, the city switched back to its own water supply after successfully lowering the PFAS levels. However, it’s important to note that Cambridge boasts some of the strictest PFAS regulations in the US, whereas many other cities and states have no regulations at all. This suggests that the contamination in Cambridge’s water wasn’t unusually high, but rather that people elsewhere may have been unknowingly consuming higher levels of PFAS.

Recently, the US Environmental Protection Agency (EPA) finalized the first PFAS National Primary Drinking Water Regulation, and the US Food and Drug Administration (FDA) banned PFAS in food packaging. Both actions are critical steps toward reducing PFAS exposure and protecting public health. The fight against PFAS contamination, however, is far from over. Continued research, stricter regulations, and heightened public awareness remain essential in safeguarding future generations. It falls on all of us to advocate for cleaner, safer environments and to prevent “forever chemicals” from resulting in “forever health problems.”

About the Author:
Mingyu Zhang is an epidemiologist and faculty member in the Department of Medicine at Beth Israel Deaconess Medical Center, Harvard Medical School. He is a Co-Investigator of Project Viva. Previously, Mingyu worked as a Research Fellow at the Harvard Pilgrim Health Care Institute. The primary goal of his research program is to understand how environmental exposures shape disease risks and impact cardiometabolic health across the life course.