Arsenic Reduction in Drinking Water and Improvement in Skin Lesions: A Follow-Up Study in Bangladesh

BACKGROUND Chronic exposure to arsenic is associated with skin lesions. However, it is not known whether reducing arsenic exposure will improve skin lesions. OBJECTIVE We evaluated the association between reduced arsenic exposures and skin lesion recovery over time. METHODS A follow-up study of 550 individuals was conducted in 2009-2011 on a baseline population of skin lesion cases (n = 900) previously enrolled in Bangladesh in 2001-2003. Arsenic in drinking water and toenails, and skin lesion status and severity were ascertained at baseline and follow-up. We used logistic regression and generalized estimating equation (GEE) models to evaluate the association between log10-transformed arsenic exposure and skin lesion persistence and severity. RESULTS During the study period, water arsenic concentrations decreased in this population by 41% overall, and 65 individuals who had skin lesions at baseline had no identifiable lesions at follow-up. In the adjusted models, every log10 decrease in water arsenic and toenail arsenic was associated with 22% [odds ratio (OR) = 1.22; 95% CI: 0.85, 1.78] and 4.5 times (OR = 4.49; 95% CI: 1.94, 11.1) relative increase in skin lesion recovery, respectively. In addition, lower baseline arsenic levels were significantly associated with increased odds of recovery. A log10 decrease in toenail arsenic from baseline to follow-up was also significantly associated with reduced skin lesion severity in cases over time (mean score change of -5.22 units; 95% CI: -8.61, -1.82). CONCLUSIONS Reducing arsenic exposure increased the odds that an individual with skin lesions would recover or show less severe lesions within 10 years. Reducing arsenic exposure must remain a public health priority in Bangladesh and in other regions affected by arsenic-contaminated water.