Whole blood mercury and the risk of cardiovascular disease among the Greenlandic population

Background: Studies have found mercury to be associated with cardiovascular disease (CVD), however, primarily in populations with low exposure. The highest levels, and variations in the levels, of whole blood mercury (WBM) worldwide have been found in Greenland. We prospectively assessed the association between WBM and the risk of developing CVD in the Greenlandic population. Methods: We assessed the effects of WBM levels on incident CVD among 3083 Greenlandic Inuit, participating in a population-based cohort study conducted from 2005 to 2010. WBM was measured at baseline. Participants were followed in the National Patient Registries for Denmark and Greenland and in the causes of death register for CVD events from inclusion in the study until CVD event, emigration, death or end of follow-up (30/9-2013). Using Cox regression analyses, we calculated the incidence rates and the hazard ratio of CVD events according to WBM levels. Potential interactions with sex were also investigated. Results: The highest levels of WBM were found in men, who had a significantly higher median level (19 mu g/L (IQR:1-44)), compared with women (15 mu g/L (IQR: 1-32), (p < 0.001)). The crude hazard ratio (HR) for incident CVD was 1.00 (95% CI 1.00-1.00) for 5 mu g/l increase in WBM. After adjusting for several potential confounders, there was still no association between WBM and incident CVD (HR 0.99; 95%CI:0.99-1.00). We found no interactions with sex. Conclusions: In a population with high levels of WBM, we found no association between WBM and the risk of developing CVD in Greenland.