Potentially toxic ‘forever chemicals’ may harm kids during critical period for bone development

The forearm is particularly vulnerable, researchers found in a new study on PFAS exposure and bone health. (BSIP/Collection Mix: Subjects RF/Getty Images/File via CNN Newsource)

The “forever chemicals” known as PFAS are increasingly known to potentially pose many threats, the latest of which may be child bone health, according to a new study.

Perfluoroalkyl and polyfluoroalkyl substances, or PFAS, are a class of about 15,000 synthetic chemicals commonly used in products such as clothing, nonstick cookware, firefighting foams, food packaging, carpets, cleaning products, paints, and stain and water repellents. These compounds do not break down in the environment and can easily migrate into the air, dust, food and soil, also contaminating nearly half the drinking water in the United States.

Notably, PFAS accumulate in our bodies and have been found in the blood of people of all ages, including newborns.

“After you’re born, you start to accrue bone density, and you do it really rapidly through adolescence,” said Dr. Jessie Buckley, first author of the small study published Tuesday in the Journal of the Endocrine Society. “Then after around age 20 or so, you have reached all the bone density you’ll ever get, and it’s all downhill after that.”

“We found that PFAS chemical exposure in children tended to be related to lower bone strength when they’re young teens,” added Buckley, professor in the department of epidemiology at the University of North Carolina at Chapel Hill. “This was particularly true for one chemical, PFOA. It didn’t really matter when the exposure happened; it was consistently related to lower bone density, particularly in their forearm.”

Part of the PFAS class, PFOA is perfluorooctanoic acid — historically one of the most widely used and studied PFAS chemicals in the U.S.

The findings suggest “these chemicals may be causing folks to not reach their genetic potential for bone density,” potentially raising risk for fractures and osteoporosis in older adulthood, Buckley said.

Hundreds of studies have linked PFAS exposure with serious health problems, including cancers, endocrine disruption, reproductive issues, high cholesterol, weight gain, weakened childhood immunity and low birth weight.

Limiting PFAS exposures

Learning what your water utility is doing to reduce PFAS in your drinking water is one of the most important things you can do to curb your exposure, experts told CNN in a May report. Utilities may be testing and making the data publicly available.

At home, you can use a water filter independently certified by the NSF, formerly the National Sanitation Foundation, or another official lab. Reverse osmosis filters are most effective but also more expensive.

You can also avoid using conventional nonstick cookware and opt for ceramic, glass, cast-iron or stainless steel instead. Not consuming foods in fast-food wrappers, takeout containers and pizza boxes can also help since those are a significant source of dietary exposure to PFAS.

PFAS and child bone health

Buckley and other researchers have discovered associations between mothers’ PFAS exposures during pregnancy and their children’s lower bone density before.

“This study extends that by looking at the child’s own exposure throughout their life,” Buckley said.

The new study was on 218 children who had been part of a research cohort since birth. At the participants’ births, via the umbilical cord, and when they were ages 3, 8 and 12, authors studied their blood serum concentrations of four PFAS chemicals — PFOA, PFOS (perfluorooctane sulfonic acid), PFNA (perfluorononanoic acid) and PFHxS (perfluorohexane sulfonic acid). The research team measured bone density in six areas once the children had turned 12.

Children with higher PFAS levels had lower bone mineral density compared with participants who had the lowest amounts of PFAS chemicals.

Buckley said the way she and her coauthors calculated the bone mineral density, or BMD, scores of children with the highest or lowest PFAS levels doesn’t cleanly translate to percentage changes. But she noted the difference in scores is similar to the amount associated with roughly 10% to 30% higher odds of forearm fracture in childhood, based on previous research.

“Importantly, these BMD scores are as larger or larger than those reported for other recognized influences on adolescent bone health, such as diet quality, physical activity or genetic risk,” Buckley said.

For the chemicals besides PFOA, links to bone health depended more on time of exposure.

The research team found the highest PFAS concentrations when participants were age 3, which were associated with higher bone density at age 12, Buckley said — contrasting with the finding of lower adolescent bone density when the children had high PFAS levels closer to the preteen years.

This finding may indicate that PFAS exposure from ages 8 to 12 may have a greater impact than exposure during the toddler years, especially among girls, Buckley said. High chemical levels at age 3 may stem partly from PFAS transfer through breast milk from the mother, who naturally has accumulated chemicals over her lifetime, she added. That doesn’t mean people should avoid breastfeeding, Buckley said, noting its many benefits, including infant bone health.

“The benefits of breastfeeding outweigh the potential PFAS-related risks,” said Dr. Lida Chatzi, professor of population and public health sciences at the University of Southern California, via email. Chatzi wasn’t involved in the study.

Researchers have posed many hypotheses on the potential mechanisms by which PFAS levels might weaken bone health. “PFAS are endocrine-disrupting chemicals,” Buckley said. “Our hormones have a lot to do with our bones development and function, so if we are disrupting estrogen and testosterone and thyroid hormones, this can impact … how our bones are maintained.”

Another possibility is that PFAS may turn our stem cells into fat cells instead of bone cells, she said.

“Finally, PFAS have been detected directly in human bone tissue, suggesting they may accumulate in bone and potentially contribute to skeletal toxicity,” said Chatzi, who is also director of the USC Superfund Research and Training Program for PFAS Assessment, Remediation and Prevention Center.

What questions remain

The study also has a few limitations, Chatzi said, including its relatively small sample size. Additionally, while age 12 is an important time for bone development, it’s still before peak bone mass. “So, we don’t yet know whether these differences will persist, widen, or disappear by late adolescence or adulthood,” she added.

More long-term studies will be important for learning more, especially about any potential consequences, Buckley said. Associations between PFAS exposure, lower bone density and higher risk of osteoporosis have been found in adults, but both factors were measured at one point in time — which cannot prove as much as long-term research might.