• Posted October 7, 2024

PFAS 'Forever Chemicals' Could Disrupt Sleep

Researchers at the University of Southern California (USC) have broken new ground, linking "forever chemicals" in the blood to poor sleep.

Their research -- published in the October issue of the journal Environmental Advances -- is the first to explore links between blood levels of four types of per- and polyfluoroalkyl (PFAS) chemicals and sleep. 

Their study included more than 140 19- to 24-olds who had given blood samples several years apart as part of a separate USC health study. They also described the duration and quality of their sleep.

Four forever chemicals had significant links to sleep quality or duration, researchers found.

"Sleep quality is an issue that affects almost everybody, so the impact of PFAS on sleep may have policy implications," said study co-author Shiwen (Sherlock) Li, a postdoctoral researcher at Keck School of Medicine of USC. 

"Long term, poor sleep has been connected to outcomes including neurological and behavioral problems, type 2 diabetes and Alzheimer's disease," Li added in a university news release.

PFAS chemicals can persist in the environment for decades. They are found in many consumer products, from nonstick cookware to shampoo. They may also be ingested with food and water. Researchers noted that the vast majority of Americans have detectable levels in their blood.

Four of seven types of PFAS examined were linked to sleep problems — PFDA, PFHxS, PFOA and PFOS.

Study participants with the highest blood levels of the first  three of those chemicals slept, on average, about 1 hour and 20 minutes less every night than participants with the lowest levels. 

High PFOS blood levels were associated with problems falling sleep, staying asleep, waking up or feeling tired during the day, researchers said.

The four chemicals were widely used from the 1950s to early 2000s, but they have been largely phased out in favor of other compounds whose safety is unknown.

"What we measured in the blood is likely driven by exposure since birth, or even prenatal exposure," Li said.

Drawing from databases that compile research linking chemicals, diseases and changes in gene expression to analyze the four types of PFAS, Li's team looked at links between PFAS-affected genes and genes related to sleep disorders. 

Of more than 600 gene candidates, seven activated by PFAS seemed to affect sleep, researchers said. One was an immune-oriented gene that helps produce the hormone cortisol. Cortisol plays a big part in regulating sleep-wake rhythms.

Cathepsin B, another gene that seems to play an important role, is related to memory and thinking skills, including development of the plaques found in the brains of Alzheimer's patients. Alzheimer's has its own links to sleep issues.

More information

The U.S. Food and Drug Administration has more about "forever chemicals."

SOURCE: Keck School of Medicine of USC, news release. Oct. 4, 2024