Arsenic exposure and young adult's mortality risk: A 13-year follow-up study in Matlab, Bangladesh.

Background: Widespread arsenic contamination in underground water is a well-documented public health concern that threatens millions of lives worldwide. We investigated the risk of young-adult mortality due to high chronic exposure to arsenic through years of drinking arsenic contaminated water.

Methods: A prospective cohort study of 58,406 individuals was enrolled who were 4-18 years at baseline. Since Matlab HDSS (Health and Demographic Surveillance System) has an active surveillance system, all individuals were included in the follow up. Each individual's arsenic exposure was calculated at (1) baseline As level as current exposure (2) time-weighted lifetime (average or lifetime average) and (3) cumulative arsenic exposure. Age, sex, educational attainment and SES were adjusted during the analysis. In this 13 years closed-cohort study (2003-2015), all young-adult deaths were captured through verbal autopsy (VA) using International Classification of Diseases (ICD-10) to define the causes.

Results: Although, girls had higher values of cumulative arsenic exposure via tube well water than boys (median: 1858.5 μg/year/L vs. 1798.8 μg/year/L) but higher mortality due to cancers and due to cerebro-vascular disease, cardio-vascular disease, and respiratory disease (7.0 vs. 5.7 per 100,000 person-years and 6.4 vs. 4.2 per 100,000 person-years respectively). Higher risk of deaths among young adults (Adjusted HR: 2.7, 1.3-5.8) due to all cancers among those who were exposed to As > 138.7 compared to As ≤ 1.1 μg/L. For cerebro-vascular disease, cardio-vascular disease, and respiratory disease deaths, average arsenic in well water (>223.1 μg/L vs. ≤90.9 μg/L) and cumulative arsenic in well water (>2711.0 μg/year/L vs. ≤1013.3 μg/year/L) had 4.8 (1.8-12.8) and 5.1 (1.7-15.1) times higher risks of mortality than to those lowest exposed.

Conclusion: Higher concentration of, and chronic exposure to arsenic in drinking water, increases the mortality risk among the young adults, regardless of gender.