Perfluoroalkyl chemicals and elevated serum uric acid in US adults

BACKGROUND Perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, are man-made chemicals that have been detected in the blood of over 98% of the US population. Serum uric acid is a novel biomarker, even mild elevations of which has been implicated in the development of hypertension, diabetes mellitus, cardiovascular disease, and chronic kidney disease. We examined the relationship of serum perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, and elevated uric acid levels in a representative sample of US adults. METHODS We examined 3883 participants from the 1999-2000 and 2003-2006 National Health and Nutritional Examination Surveys, a representative, multiethnic population-based survey of noninstitutionalized US adults. Serum perfluorooctanoic acid and perfluorooctane sulfonate were analyzed as quartiles. The main outcome was hyperuricemia. RESULTS We found that serum levels of perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, were positively associated with hyperuricemia. This association appeared to be independent of confounders such as age, gender, race-ethnicity, body mass index, diabetes, hypertension, and serum cholesterol. Compared with subjects in quartile 1 (referent), the multivariate odds ratio for hyperuricemia among subjects in quartile 4 was 1.97 (95% confidence interval 1.44-2.70, P < 0.0001) for perfluorooctanoic acid and 1.48% (95% confidence interval 0.99-2.22, P = 0.0433) for perfluorooctane sulfonate. This observed association persisted in subgroup analysis by gender and body mass index. CONCLUSION Our results demonstrate that elevated levels of perfluoroalkyl chemicals are associated with hyperuricemia even at low perfluoroalkyl chemical exposure levels as seen in the US general population.