PFAS 'forever chemicals' linked to poor sleep

[New Sancai Compilation and First Release] Researchers at the University of Southern California (USC) have made a new breakthrough, linking "permanent chemicals" in the blood to poor sleep.

Their study, published in the October issue of the journal Environmental Advances, is the first to examine the link between blood levels of four per- and polyfluoroalkyl (PFAS) chemicals and sleep.

Their study included more than 140 young people, ages 19 to 24, whose blood samples were taken several years apart in a separate health study conducted at the University of Southern California. They also described the duration and quality of sleep.

Researchers found that four chemicals were significantly associated with sleep quality or duration.

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

"In the long term, poor sleep quality is associated with consequences such as neurological and behavioral problems, type 2 diabetes, and Alzheimer's disease," Lee added in a university news release.

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

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

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

Researchers say high PFOS blood levels are associated with problems falling asleep, staying asleep, waking up, or feeling tired during the day.

These four chemicals were widely used from the 1950s to the early 2000s, but they have largely been phased out and replaced by other compounds of unknown safety.

"What we measured in the blood could be caused by postnatal exposure or even prenatal exposure," Li said.

Li's team analyzed four types of PFAS using a database that compiles studies linking chemicals, disease and changes in gene expression, looking at links between genes affected by PFAS and genes associated with sleep disorders.

The researchers said that of more than 600 candidate genes, seven activated by PFAS appear to affect sleep. One is an immune-directed gene that helps produce the hormone cortisol. Cortisol plays an important role in regulating sleep-wake rhythms.

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

(Compiled by: Wang Jimin)

(Editor: Jiang Qiming)

(Source of the article: Compiled and published by New Sancai)