Some of the most common types of PFAS may cause sleep disorders in young adults, new research finds, and the study’s authors for the first time identified how the chemicals probably impact the brain to cause disruptions.
The peer-reviewed University of Southern California (USC) study looked at PFAS levels in the blood of adults between 19 and 24 years old, and found those in the highest one-third slept an average of about 80 fewer minutes nightly than those in the lowest third.
For PFOS, a common compound, high blood concentrations were linked strongest to problems falling asleep, staying asleep, waking up or feeling tired during waking hours.
“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 Li, the study’s lead author and a postdoctoral researcher at USC.
PFAS are a class of about 15,000 chemicals typically used to make products that resist water, stains and heat. They are called “forever chemicals” because they do not naturally break down, and they accumulate in humans and the environment. The chemicals are linked to cancer, kidney disease, liver problems, immune disorders, birth defects and other serious health problems.
PFAS are also increasingly linked to neurological diseases, including Alzheimer’s, anxiety disorders and ADHD, though the study’s authors say epidemiological studies are needed to provide a clearer picture of brain impacts.
However, the study found very strong evidence of why the chemicals could affect sleep quality. Its authors checked a panel of proteins – the products of the blueprints inscribed in genes – from participants’ blood samples, and found seven genes that are probably activated by PFAS that seem to influence sleep.
Among those are a gene that converts cortisol to cortisone, a stress response hormone that also regulates sleep cycles.
“There’s a very strong biological pathway that we’re seeing – it’s not just observational,” Li said.
The chemicals also probably affect sleep, and potentially cognitive function and memory, because they target the cathepsin B gene. High levels of the resulting enzyme have been linked to cognitive decline in Alzheimer’s, which is also thought to stem from sleep disorders.
While the study found PFOS, one of the most common and toxic PFAS compounds, had the strongest links to sleep disruption, high levels of mixtures were also found to cause problems.
Previous research has found PFAS can probably cross the blood-brain barrier and disrupt the levels of neurotransmitters, like dopamine, glutamate and serotonin, and calcium homeostasis, which are all important for sleep health.
Meanwhile, a recent Chinese study of more than 4,100 pregnant women and their infants found the chemicals seemed to cause sleep disturbance, lower sleep efficiency, and shorter sleep duration across three trimesters for mothers and, after birth, for their children.
There is little that those with higher levels of PFAS in their blood can do beyond to avoid potential exposures via common routes like drinking water, food or household consumer products.
Some PFAS have a half-life – or the amount of time it takes to remove half the chemicals from a person’s blood – of several years, meaning it can take decades for the body to expel the highest levels. The research highlights the need for stronger regulations, the paper states.
“The problem is PFAS is a group of thousands of compounds so there should be discussions about regulating them as a chemical class,” Li said.
