Abstracts: ISEE 20th Annual Conference, Pasadena, California, October 12-16, 2008: Contributed Abstracts
High-chronic exposure to inorganic arsenic in drinking water has been related to diabetes development in Taiwan, Bangladesh and Mexico. However, the effect of exposure to low-moderate levels of inorganic arsenic on diabetes risk is unknown. In contrast, arsenobetaine, an organic arsenic compound derived from seafood intake, is considered non-toxic.
To investigate the association of arsenic exposure, as measured in urine, with the prevalence of diabetes in a representative sample of US adults.
Cross-sectional study in 998 adults ≥20 y who participated in the 2003–2004 National Health and Nutrition Examination Survey (NHANES) and had urine arsenic determinations. Total arsenic and arsenic species (arsenite, arsenate, methylarsonate [MA], dimethylarsinate [DMA], and arsenobetaine) were measured at the Environmental Health Sciences Laboratory of the National Center for Environmental Health using inductively coupled-plasma dynamic reaction cell-mass spectrometry (ICP-DRC-MS) and high performance liquid chromatography (HPLC)-ICP-DRC-MS, respectively. 96%, 92%, 65%, 16% and 28% of sample participants had arsenite, arsenate, MA, DMA and arsenobetaine levels below the limit of detection, respectively. Diabetes was defined as a fasting serum glucose ≥126 mg/dL, a self-reported physician diagnosis of diabetes, or self-reported use of insulin or oral hypoglycemic medication.
The median urine levels of total arsenic, DMA and arsenobetaine were 8.3, 4.0, and 1.1 μg/L, respectively. After adjustment for diabetes risk factors and markers of seafood intake (the main source of organic arsenicals), participants with diabetes had 20% higher total arsenic, 8% higher DMA, and similar arsenobetaine levels than participants without diabetes. Consistently, the odds ratios (95% confidence interval) for diabetes were 3.08 (1.31, 7.25), 1.45 (1.07, 1.96), and 0.86 (0.43, 1.71) comparing participants at the 80th vs. the 20th percentiles of total arsenic, DMA and arsenobetaine levels, respectively. The positive association between total urine arsenic and diabetes after adjustment for markers of seafood intake was consistent for subgroups defined by sex, age, race, body mass index, smoking status, and alcohol intake, and among participants who had no seafood intake in the past 24 h.
After adjustment for seafood intake, total urine arsenic and urine DMA, but not arsenobetaine, were associated with increased prevalence of diabetes. These findings support the hypothesis that low levels of exposure to inorganic arsenic in drinking water, a widespread exposure worldwide, may play a role in diabetes. Elucidating the contribution of inorganic arsenic exposure to the diabetes epidemic is a public health research priority.