High blood levels of a chemical used in non-stick and stain-resistant coatings for pots and pans, furniture, clothing and other widely used products have been linked to an increased risk of osteoarthritis in a study of people exposed to contaminated drinking water.
Those with the highest levels of this chemical – perfluorooctanoate, or PFOA – in their bodies were 40 percent more likely to have osteoarthritis, or OA, than those in the study who had the lowest levels.
On the other hand, blood levels of a sister compound called perfluorooctane sulfonate, or PFOS, were inversely associated with OA – that is, the higher the blood levels, the less likelihood of having OA.
“While our findings suggest exposure to these chemicals may be linked to osteoarthritis risk, no conclusions regarding cause and effect can be drawn due to the cross-sectional nature of the study. Clearly, more research is warranted,” explains lead author Kim Innes, PhD, an associate professor at the School of Medicine at West Virginia University in Morgantown, in an email.
The study, which was published online in the June 2011 American Journal of Epidemiology, included almost 50,000 adults who lived in six different districts in West Virginia and Ohio where water was contaminated with PFOA and PFOS by a DuPont Chemical plant. These people participated in a 2001 class-action lawsuit against DuPont and were being monitored as part of a 2004 settlement.
PFOA and PFOS are organic pollutants that, once released, persist in the environment and remain in the human body for several years. Study participants were given a full health survey and had blood measurements of levels of PFOA, PFOS and other chemicals. The participants also provided a full medical history, including physician diagnosis of OA.
Nearly 8 percent of the participants were found to have OA. The connection between PFOA and OA was strongest in younger people and non-obese people.
This study does not show a direct cause and effect. However, Innes says, “If these associations [for PFOA and PFOS] are confirmed in large prospective studies in people free of osteoarthritis at baseline, public health implications could be substantial, given the high prevalence and costs of this disorder.”
“The study is important, because toxicity studies of chemicals do not necessarily look at the effects on joints first,” commented Robin Poole, PhD, scientific director emeritus of the Canadian Arthritis Network, A National Centre of Excellence. Any effect – direct or indirect – on arthritis may be missed if the joints are not the first priority when looking at the pathology of chemicals, Poole says.
At this point in time, specific recommendations regarding PFOA would be premature, Innes says, “but it is always wise to limit exposure to any known environmental pollutant, as many, including PFOA, may have negative effects on human health.”