Association of water arsenic with incident diabetes in U.S. adults: The Multi-Ethnic Study of Atherosclerosis and The Strong Heart Study

Abstract

<p dir="ltr">Objective: We examined the association of arsenic in federally regulated community water systems (CWS) and unregulated private wells with type 2 diabetes (T2D) incidence in the Strong Heart Family Study (SHFS), a prospective study of American Indian communities, and the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective study of racially/ethnically diverse urban U.S. communities.</p><p dir="ltr">Research Design and Methods: We evaluated N=1,791 participants from SHFS and N=5,777 participants from MESA with water arsenic estimates available and free of T2D at baseline (2001-2003 and 2000-2002, respectively). Participants were followed for incident T2D until 2010 (SHFS) or 2019 (MESA). We used Cox proportional hazards mixed-effects models to account for clustering by family and residential zip code, with adjustment for sex, baseline age, body mass index (BMI), smoking status, and education.</p><p dir="ltr">Results: T2D incidence was 24.4 cases per 1,000 person-years (mean follow-up 5.6 years) in SHFS and 11.2 per 1,000 person-years (mean follow-up 6.0 years) in MESA. In a meta-analysis across SHFS and MESA, the hazard ratio (95% confidence interval) per doubling in CWS arsenic was 1.10 (95%CI 1.02, 1.18). The corresponding hazard ratio was 1.09 (0.95, 1.26) in SHFS and 1.10 (1.01, 1.20) in MESA. The corresponding hazard ratio (95%CI) for arsenic in private wells and incident T2D in SHFS was 1.05 (0.95, 1.16). We observed statistical interaction and larger magnitude hazard ratios for participants with BMI <25 kg/m2 and female participants.</p><p dir="ltr">Conclusions: Low to moderate water arsenic levels (<10 µg/L) were associated with T2D incidence in the SHFS and MESA.</p>