Research Links ‘Forever Chemicals’ to Disrupted Sleep in Young Adults

New research reveals that exposure to certain “forever chemicals” may be disrupting the sleep quality of young adults, contributing to not only tiredness but also potential health risks. A study from the University of Southern California, recently published in *Environmental Advances*, found that individuals with elevated levels of four specific per- and polyfluoroalkyl substances (PFAS) in their blood experienced poorer sleep quality.

PFAS, often referred to as “forever chemicals” because they persist in the body and environment, may interfere with the function of a key gene involved in producing the hormone cortisol. Cortisol plays a crucial role in regulating sleep and wakefulness patterns, and disruptions to this hormone can affect sleep, the study authors noted.

“Because the body needs sleep every day, if PFAS might be interfering with your sleep, that may affect you more immediately than other chronic health issues,” said Shiwen (Sherlock) Li, lead author of the study and a postdoctoral researcher at USC’s Keck School of Medicine, in a statement.

There are thousands of types of PFAS, some of which are linked to illnesses like kidney cancer, testicular cancer, and thyroid disease. These chemicals are commonly found in firefighting foams, industrial waste, household products, cosmetics, and waterproof apparel.

Building upon previous knowledge that PFAS can disrupt hormones and the immune system, the USC researchers collected blood samples and sleep data from 144 participants aged 19 to 24. These young adults were part of the USC Children’s Health Study, a long-term research project studying the effects of pollutants on children.

The study was conducted in two phases. The first phase involved data collection from 136 participants between 2014 and 2018. The second phase, which took place between 2020 and 2022, reassessed 76 of these participants, while also including an additional eight individuals.

The researchers measured blood concentrations of seven PFAS compounds: PFOS, PFOA, PFHxS, PFHpS, PFPeS, PFNA, and PFDA. They then assessed the participants’ sleep duration based on self-reports and used validated tools to track sleep disturbances.

Of these seven chemicals, four—PFDA, PFHxS, PFOA, and PFOS—were significantly associated with poor sleep quality or shorter sleep duration, according to the findings.

Even though PFOA and PFOS are considered “legacy PFAS” and have largely been phased out of production, they remain widely present in the environment.

“It could be a matter of cumulative exposure over time,” Li explained. “What we measured in the blood is likely driven by exposure since birth, or even prenatal exposures.”

The study found that individuals with higher blood levels of PFDA, PFOA, and PFHxS had notably shorter sleep duration. Specifically, those with the highest levels of these compounds slept an average of 80 minutes less each night compared to those with the lowest levels.

Meanwhile, PFOS was linked to increased sleep disturbances and sleep-related impairments. Affected participants reported difficulty falling or staying asleep, trouble waking up, and feeling tired during the day.

The research team delved deeper to understand why these chemicals might be impacting sleep quality. They examined potential connections between PFAS exposure and genes associated with sleep disorders by utilizing toxicology databases that map relationships between chemicals, diseases, and changes in gene expression.

They identified more than 600 possible candidate genes and narrowed down their focus to seven that appeared to be activated by PFAS exposure and were also associated with sleep regulation.

One of the genes, HSD11B1, is involved in producing cortisol. The hormone plays an essential role in controlling sleep and wakefulness rhythms. Disruptions to the expression of the protein encoded by this gene could lead to altered cortisol levels, which, in turn, could affect sleep, according to the study.

“If the expression of the protein encoded by HSD11B1 is disrupted, that means that cortisol levels could also be disrupted,” Li said. “That, in turn, affects sleep.”

Another gene of interest was cathepsin B, which produces enzymes that are precursors to amyloid beta proteins. These proteins are commonly found in the brains of Alzheimer’s patients. High levels of cathepsin B have previously been linked to cognitive decline in Alzheimer’s disease, which itself has been associated with sleep deficits, the researchers explained.

The findings are significant because they suggest that PFAS exposure may contribute to broader health consequences through its impact on sleep. The team plans to continue exploring the effects of forever chemicals on children’s sleep as part of a larger National Institutes of Health initiative.

“Sleep quality is an issue that affects almost everybody, so the impact of PFAS on sleep may have policy implications,” Li added.

This research underscores the potential public health concern related to PFAS exposure and its effects on sleep, especially in young adults. As these chemicals continue to persist in the environment, the findings highlight the need for further studies and possibly regulatory changes to address the presence of PFAS in everyday products.