Levels of perfluoroalkyl substances and risk of coronary heart disease: Findings from a population-based longitudinal study.

BACKGROUND: Cross-sectional studies have shown an association between exposure to perfluoroalkyl substances (PFASs) and coronary heart disease (CHD). These findings need to be evaluated in longitudinal settings. OBJECTIVES: To investigate the risk of CHD in relation to PFAS levels in a longitudinal setting among Swedish rural residents. METHODS: In a population-based prospective cohort of male farmers and rural residents recruited in 1990-1991, all men who received a CHD diagnosis between 1992 and 2009 were identified from national registers (n=253). For each CHD case, one control, matched for age, was chosen randomly from the cohort. For all cases and controls, levels of eight PFASs at baseline were measured in stored blood samples. In addition, for a subsample, PFAS levels were also measured in serum samples collected at a follow-up in 2002-2003. RESULTS: There were no statistically significant associations between levels of seven of the eight PFASs at baseline and risk for developing CHD. There was a significant association between perfluoroheptanoic acid (PFHpA) and CHD (OR=2.72; 95% CI: 1.52, 4.84) for the 3rd quartile and (OR=2.45; 95% CI: 1.40, 4.29) for the 4th quartile compared to the lowest quartile. Changes in levels of PFCs between baseline and follow-up did not differ systematically between cases and controls. CONCLUSIONS: This longitudinal study does not lend support to the previously reported cross-sectional relationship between PFAS levels and CHD risk. We found a significant association with PFHpA, but this could be a chance finding, considering its chemical resemblance to other PFASs.