By Megan Boland
A recent study by NIEHS-funded researchers investigated links between developmental per- and polyfluoroalkyl substances (PFAS) exposure and reduced bone density in childhood and adolescence. Led by Annelise Blomberg, Sc.D., of the Harvard University School of Public Health and Lund University, the study has important implications for children’s health.
PFAS are manmade chemicals used in a variety of products ranging from firefighting foams to non-stick cookware. Often referred to as “forever chemicals,” PFAS are difficult to break down and are found across the globe in air, water, and soil.
Human exposure to PFAS is widespread and has been linked to many adverse health outcomes, including birth outcomes, cancer, thyroid dysfunction, and high cholesterol.
There is also evidence that PFAS is associated with lower bone mass density, a measure of bone health and an important determinant of osteoporosis risk.
Faroe Islands Birth Cohort
To understand the impacts of PFAS on bone density, the study leveraged an existing birth cohort — a group of children followed from birth through their lives — in the Faroe Islands, a fishing community west of Norway. No manufacturing of PFAS takes place on the islands, but the community is exposed through consumer products and their traditional diet of whale meat.
"PFAS exposures are a global problem," said Blomberg. "Even PFAS that have been phased out of production are still found in our environment and our bodies."
Previous research in the Faroe Islands has found an association between PFAS exposures and decreased birth size. Children are likely exposed to PFAS via breast milk, diet, and consumer products, and are more vulnerable to PFAS since their bones and bodies are still developing.
“Children are exposed in different ways and have much smaller bodies,” explained Blomberg. “During prenatal and early childhood periods, systems are changing fast — if children are exposed to chemicals, it has the potential for longer-term health outcomes.”
PFAS and Children’s Bone Health
To assess whether PFAS may affect bone health, the team measured five of the most commonly detected PFAS in 366 participants at birth and at 18 months, 5 years, and 9 years of age. They conducted a bone mass density assessment at age nine.
The researchers found that higher concentrations of PFAS at age 18 months and 5 years were associated with decreased bone mass density measures at age 9, with the strongest effect for perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) exposures at age 5.
Next, the team investigated whether body composition — including body mass index (BMI), body fat, and lean mass — could explain these associations between PFAS and bone mass density.
PFAS exposures at age 5 were generally not associated with body composition, but exposure at 18 months may affect both bone mass and body composition. This suggests that differing mechanisms may be at play for PFAS exposures at different developmental stages and highlights potential sensitive windows of exposure.
“Early PFAS exposures may impact the accrual of bone mass density throughout childhood, which can impact long term risk of osteoporosis,” Blomberg noted. “While further studies are needed to evaluate associations of PFAS exposures with clinical outcomes like fractures, the associations found in this study support the possibility that bone may be a target tissue for developmental PFAS toxicity in humans.”
NIEHS PFAS Research
NIEHS and the National Toxicology Program (NTP) support research to better understand the health effects, remediation, and detection of PFAS. To date, over 700 NIEHS-funded publications have contributed to our understanding of PFAS.
Results from some of these studies have found associations between PFAS and children’s cognitive health, diabetes, liver injury, and metabolism. Researchers also find novel ways to detect PFAS in environment, including the use of pine needles as passive samplers and the development of portable detection tools. In an effort to remove PFAS from the environment, researchers have used plants, fungi, and solar powered nanomaterials as remediation strategies.
The Superfund Research Program (SRP) within NIEHS supports multiple institutions participating in PFAS research. Researchers have found signs of immune disruption in alligators living in PFAS-contaminated waters, elevated cholesterol levels in residents with PFAS in their drinking water, and PFAS-associated increases in lipid accumulation in human cells. To remediate PFAS, researchers developed membranes and a water pitcher filter to remove PFAS from water. Grantees also translate research findings to inform drinking water health advisories issued by the U.S. Environmental Protection Agency (EPA) for several types of PFAS.