DERT Stories of Success
PFCs in the United States
PFCs are highly persistent in the environment and are widely used in food packaging and textiles because of their stain-resistant and water-repellant properties. The U.S. Environmental Protection Agency has been working with the U.S. chemical industry to reduce production and emission of some of the most common PFCs, including perfluorooctanoic acid (PFOS) and perfluorooctane sulfonic acid (PFOA). PFC concentrations measured from blood samples are roughly the same in the United States and the Faroe Islands. Grandjean says that the concentrations of PFOS and PFOA in people are decreasing in the United States, but he is concerned that concentrations of alternative PFCs are beginning to increase. It is difficult to identify products containing PFCs, but PFC-free labels are beginning to appear on some products such as rain gear.
Philippe Grandjean, M.D.
NIEHS grantee Philippe Grandjean, M.D., published one of the first studies to link childhood exposure to perfluorinated compounds (PFCs) with immune system deficiency. The study showed that higher levels of exposure to PFCs were associated with reduced immune responses in children, and the results point to the importance of assessing the immunotoxic potential of PFCs. In addition, the immunotoxic effects of PFCs or other environmental contaminants might address variation in vaccine efficacy that have puzzled scientists.
As described in a JAMA paper, Grandjean and his colleagues studied the immunotoxic effects of PFCs by following about 600 children from the Faroese Islands. The people of these islands are exposed to a wide variety of contaminants because they frequently consume food from the ocean.
“We’ve worked with this community for 25 years and have been very successful in conducting population studies,” says Grandjean, an adjunct professor of environmental science at the Harvard School of Public Health in Boston. “We have a record of doing something that is useful to the community and also useful to science.”
The investigators assessed prenatal exposure by measuring PFCs in the mother’s serum during pregnancy and later checked for the compounds in samples from the children at age 5. They used the antibody response to childhood immunizations as an indication of how well a child’s immune system was functioning, taking measurements of antibody concentration just before the last booster shot at age 5 and again two years later.
The children with elevated exposure to PFCs showed lower antibody responses to childhood immunizations. “When the PFC exposure doubled, the child lost about half of the antibody concentration, and the risk of not being protected, even after four vaccinations, increased by a factor of two to four at age 7,” says Grandjean, who is also head of environmental medicine research at the University of Southern Denmark in Odense.
The researchers will continue to examine immune system dysfunction associated with PFC exposure, including responses to infectious disease. There are problems with vaccine efficiency around the world, and Grandjean says that immunotoxicity needs to be examined to ensure vaccinations are effective both on individual and population levels.