LIFETIME EXPOSURE TO INORGANIC ARSENIC IN DRINKING WATER AND CORONARY HEART DISEASE

Background Consumption of drinking water with high levels of inorganic arsenic (over 1000μg/L) has been associated with coronary heart disease (CHD), but previous studies have been inconclusive about risks at lower levels (<100μg/L). Objectives We conducted a case-cohort study based on individual estimates of lifetime arsenic exposure validated by historically collected urinary arsenic concentrations to examine the relationship between chronic low-level arsenic exposure and risk of CHD.

Methods This study included 555 participants with 96 CHD events diagnosed between 1984 and 1998 for which individual lifetime arsenic exposure estimates were determined using data from a structured interview to determine lifetime residence and employment history, geospatial modeling of arsenic concentrations in drinking water, and urinary arsenic concentrations. A Cox proportional hazards model with known CHD risk factors as time-dependent covariates was used to assess the association between lifetime exposure to inorganic arsenic in drinking water and incident CHD.

Results Our findings show a positive association between inorganic arsenic exposure and CHD risk (Hazard Ratio (HR) per 15 μg/L=1.38, 95%=1.06, 1.78) while adjusting for age, gender, first degree family history of CHD, and serum low density lipoprotein levels. A dose response relationship was observed between CHD risk and mean inorganic arsenic exposure in water (relative to levels below 20 μg/L, HR = 1.2 for 20-30 μg/L, 2.2 for 30-45 μg/L, and 3.1 for 45-100 μg/L).

Conclusions Exposure to inorganic arsenic in drinking water is associated with increased risk for CHD in this population based on a comprehensive lifetime exposure assessment.