Chemicals used in consumer products, including rain gear, stain-resistant carpeting, microwave popcorn bags and fast-food packaging, appear to limit children’s disease-fighting immune responses, a study found.
The research by Danish investigators is one of the first to examine the effects of perfluorinated compounds, or PFCs, on the immune system. It showed that children with the highest levels in their blood had the weakest responses to childhood vaccines. Higher chemical exposure also led to less infection-fighting antibodies to keep disease at bay, the study reported.
Decreased antibody levels may signal a weakened immune system that could have long-lasting implications, said Philippe Grandjean, the lead author and chairman of environmental medicine at the University of Southern Denmark in Odense. The reduced vaccine response suggests a rising public health threat, he said.
“If that’s true, it’s quite worrying,” said Grandjean, who also serves as an adjunct professor of environmental health at Harvard School of Public Health in Boston. “It could affect the response of the immune system to infectious diseases and how we respond to microorganisms in general.”
Environmental experts and regulators worldwide have grown increasingly concerned that perfluorinated compounds, which are both water and grease resistant, are toxic, long-lasting and can accumulate over time. The Environmental Protection Agency started restricting their use a decade ago.
Research on the human-health consequences is in the early stages, and more work is needed, the agency says.
DuPont, the largest U.S. chemicals company by market value, uses one common type of PFC as a processing aid, the company said in a statement. Trace levels of the compound, known as perfluorooctanoic acid, can be found as unintentional byproducts in some consumer products made with DuPont materials, the company said.
The company plans to stop making, buying and using the compound dubbed PFOA by 2015, and has already introduced some new products including nonstick cookware without it. Previous studies have shown existing products made with PFOAs are safe for their intended uses, the company said.
The researchers tracked 587 children born in the Faroe Islands, a fishing community located northwest of Scotland. The high consumption of seafood on the 18-island archipelago is linked to exposure to PFCs, which were at similar or lower levels seen in American children, the researchers said.
Children who had levels of major PFCs that were twice as high in their blood at age 7 as their peers also had half the antibody concentrations for tetanus and diphtheria compared with the other children, the study found.
Those with the most exposure to PFCs by age 5 were significantly more likely to have insufficient protective antibody levels two years later, the researchers said.
Prenatal exposure to PFCs reduced the children’s ability to produce antibodies years later, the study found. Higher levels of PFCs in the mother’s blood were linked to fewer antibodies produced by the children at age 5. The pollutants can be transferred through placenta and breast milk, Grandjean said.
Only a handful of medical conditions, radiation treatment and cancer drugs have a similar effect on reducing the immune system’s response to immunizations, he said.
The National Institute of Environmental Health Sciences, the EPA, the Danish Council for Strategic Research and the Danish Environmental Protection Agency funded the study. It will appear in Wednesday’s edition of Journal of the American Medical Association.
Manufacturers should look for alternatives to PFCs and phase out their use once safer products are developed, Grandjean said by telephone. Until then, consumers should look for products that are certified and marketed as PFC-free, he said.
With assistance from Jack Kaskey in Houston.