Does arsenic exposure increase the risk for circulatory disease?

Studies of residents in communities with high endemic concentrations of ars enic in drinking water suggest a deleterious effect on the circulatory syst em; however, studies among workers with high occupational exposures general ly have shown either no or weak associations. This discrepancy could be a r esult of the healthy worker effect, including the healthy hire component an d the healthy worker survivor effect (HWSE). Therefore, the authors conduct ed analyses of arsenic exposure in relation to circulatory disease mortalit y among 2,802 Tacoma, Washington, smelter workers by using 1) internal comp arisons to control for the healthy hire effect and 2) the tagging method, a djustment for employment status, and the G-null test to control for the HWS E. Both lagging and adjustment for work status increased circulatory mortal ity rate ratios at all exposure levels, as compared with a baseline Poisson model. This excess mortality was limited to cardiovascular disease; no exc ess was observed for cerebrovascular disease. G-null analyses suggested no adverse effect, but power was very limited for this analysis. Overall, thes e results may indicate that the HWSE obscures an effect of arsenic on circu latory disease. Since cardiovascular deaths constitute about one-third of t otal mortality, small rate ratios translate into large numbers of excess de aths and, if causal, could be of wide public health significance, Further s tudies of arsenic exposure and cardiovascular disease are needed, and those conducted in occupational cohorts must control for the HWSE.