Association of low to moderate levels of arsenic exposure with risk of type 2 diabetes in Bangladesh.

Chronic exposure to high levels of arsenic in drinking water is associated with increased risk of type 2 diabetes mellitus (T2DM), but the association between lower levels of arsenic and T2DM is more controversial. Therefore, this study evaluated the association between low to moderate arsenic exposure and T2DM. In 2009-2011, we conducted a study of 957 Bangladeshi adults who participated in a case-control study of skin lesions in 2001-2003. The odds ratio of T2DM was evaluated in relationship to arsenic exposure measured in drinking water and in subjects' toenails (in 2001-2003) prior to the diagnosis of T2DM (in 2009-2011). Compared with those exposed to the lowest quartile of arsenic in water (≤ 1.7 µg/L), the adjusted odds ratio for T2DM was 1.92 (95% confidence interval (CI): 0.82, 4.35) for those in the second quartile, 3.07 (95% CI: 1.38, 6.85) for those in the third quartile, and 4.51 (95% CI: 2.01, 10.09) for those in the fourth quartile. The relative excess risk of T2DM was 4.78 for individuals who smoked and 8.93 for people who had a body mass index (weight (kg)/height (m)(2)) greater than 25. These findings suggest that exposure to modest levels of arsenic in drinking water was associated with increased risk of T2DM in Bangladesh. Being overweight or smoking was also associated with increased risk of T2DM.