The “forever chemicals” known as PFAS are increasingly known to potentially have the following effects: They pose a number of threats, the latest of which may be to children’s bone health, according to new research.
Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of approximately 15,000 synthetic chemicals commonly used in products such as clothing, nonstick cookware, firefighting foam, food packaging, carpeting, cleaning supplies, paints, stain repellents, and water repellents. These compounds do not break down in the environment and easily migrate into the air, dust, food, and soil, contaminating nearly half of the drinking water in the United States.
PFAS, in particular, accumulate in our bodies and have been detected in the blood of people of all ages, including newborns.

“Bone density begins to increase after birth, and it increases very rapidly through adolescence,” said Dr. Jesse Buckley, lead author of the small study published Tuesday in the Journal of the Endocrine Society. “Then, around age 20, you reach the highest bone density you’ve ever had, but it’s all downhill from there.”
Buckley, a professor in the Department of Epidemiology at the University of North Carolina at Chapel Hill, added: “We found that exposure to PFAS chemicals in children tends to be associated with decreased bone strength during the teenage years.” “This was especially true for one chemical, PFOA. It didn’t really matter when the exposure occurred; it was always associated with decreased bone density, especially in the forearm.”
PFOA, part of the PFAS class, is perfluorooctanoic acid and has historically been one of the most widely used and studied PFAS chemicals in the United States.
The findings suggest that “these chemicals may be contributing to people not achieving their genetic potential for bone density,” potentially increasing the risk of fractures and osteoporosis in older adults, Buckley said.
Hundreds of studies have linked PFAS exposure to serious health problems, including cancer, endocrine disruption, reproductive problems, high cholesterol, weight gain, weakened childhood immunity, and low birth weight.
Knowing what water utilities are doing to reduce PFAS in drinking water is one of the most important things you can do to limit exposure, experts told CNN in a May report. Your utility company may be testing and publishing your data.
Homes can use water filters that are independently certified by NSF (formerly the National Sanitation Foundation) or another official laboratory. Reverse osmosis filters are the most effective, but also expensive.
You can also avoid using traditional nonstick cookware and choose ceramic, glass, cast iron, or stainless steel instead. It can also be helpful to avoid foods in fast food wrappers, takeout containers, and pizza boxes, as these are significant sources of dietary PFAS exposure. Detailed advice on PFAS sources can be found here.
PFAS and children’s bone health
Buckley and other researchers found a link between maternal PFAS exposure during pregnancy and earlier reductions in bone density in children.
“This study extends that by looking at children’s own lifetime exposures,” Buckley said.
The new study looked at 218 children who were part of the study cohort from birth. The authors studied serum concentrations of four PFAS chemicals: PFOA, PFOS (perfluorooctane sulfonic acid), PFNA (perfluorononanoic acid), and PFHxS (perfluorohexane sulfonic acid) when participants were born via the umbilical cord and when participants were 3, 8, and 12 years old. The research team measured bone density in six areas when the children turned 12 years old.
Children with higher PFAS levels had lower bone density compared to participants with the lowest amounts of PFAS chemicals.
Buckley said the way she and her co-authors calculated bone mineral density (BMD) scores for children with the highest or lowest PFAS levels did not reflect the change in percentages neatly. However, she noted that, based on previous research, the difference in scores is similar to the amount associated with an approximately 10% to 30% higher chance of having a forearm fracture in childhood.
“Importantly, these BMD scores are comparable to or better than those reported for other recognized influences on bone health in adolescents, such as diet quality, physical activity, and genetic risk,” Buckley said.
For chemicals other than PFOA, the association with bone health was more dependent on exposure time.
The research team found that PFAS concentrations were highest when participants were 3 years old, and this was associated with increased bone density at 12 years of age, Buckley said. In contrast, adolescents with elevated PFAS levels near age 10 were found to have lower bone density.
The findings may indicate that PFAS exposure between ages 8 and 12 may have a greater impact than early childhood exposure, particularly among girls, Buckley said. High chemical levels at age 3 may be due, in part, to the transfer of PFAS into the body. Breast milk from the mother is natural have She added that she had accumulated chemicals throughout her life. That doesn’t mean people should avoid breastfeeding, Buckley said, noting that breastfeeding has many benefits, including: infant bone health.
“The benefits of breastfeeding outweigh the potential PFAS-related risks,” Dr. Lida Chatzi, a professor of population and public health sciences at the University of Southern California, said in an email. Chatzi was not involved in the study.
Researchers have hypothesized a number of potential mechanisms by which PFAS levels compromise bone health. “PFAS are endocrine disrupting chemicals,” Buckley said. “Our hormones are highly involved in bone development and function, so disruptions to estrogen, testosterone, and thyroid hormones can affect how bones are maintained.”
Another possibility, she said, is that PFAS could cause stem cells to turn into fat cells rather than bone cells.
“Finally, the detection of PFAS directly in human bone tissue suggests that PFAS may accumulate in bone and contribute to skeletal toxicity,” Chatzi said. He is also the director of the USC Superfund Research and Training Program in the Center for PFAS Assessment, Remediation, and Prevention.
What questions remain?
Ciatzi said the study had some limitations, including a relatively small sample size. Additionally, the age of 12 is a critical period for bone development, but it is still before peak bone mass. “Thus, it remains to be seen whether these differences persist, widen, or disappear by late adolescence and adulthood,” she added.
Buckley said longer-term studies will be important, especially to learn more about potential effects. In adults, an association has been found between PFAS exposure, reduced bone density, and increased risk of osteoporosis, but both factors were measured at one point in time and cannot be as proven as in long-term studies.
Get inspired by our weekly roundup of healthy living, made simple. Sign up for CNN’s Life, But Better newsletter for information and tools to improve your health.

