Groundwater Arsenic and Fasting Blood Glucose in the Context of Other Groundwater Chemicals: A Cross-Sectional Study in Bangladesh

Abstract

Goal: To evaluate the association between groundwater arsenic (As) and fasting blood glucose (FBG), in the context of other groundwater chemicals, in Bangladesh. Methods: FBG and demographics were measured among adults ≥ 35 years of age (n=6,587) participating in the Bangladesh Demographic and Health Survey (BDHS) 2011. Groundwater chemicals in 3,534 well water samples were measured in the British Geological Survey (BGS) and Department of Public Health Engineering (DPHE) 1998-99 survey. In this analysis, we assigned the nearest BGS-DPHE well’s chemical exposure to each BDHS participant. Survey-estimation linear regression methods were used to model log-transformed FBG, among those using groundwater as primary drinking-water source, as a function of groundwater As, adjusting for age, sex, BMI, smoking status, diabetes medication use, region, rural or urban residence, household wealth, and educational attainment. We considered interactions of As with 14 other groundwater chemicals. Results: Compared to persons exposed to groundwater As < 10 mg/L, the geometric mean ratio (GMR) of FBG was 1.01 (95% confidence interval: 0.98, 1.04) for individuals exposed to groundwater As concentrations ≥10 mg/L and<50 mg/L, and was 1.01 (0.97, 1.03) for those with ≥50 mg/L water As. Low K water may have potentiated As toxicity: among persons with low water K, the GMR of FBG for the ≥10 and < 50 As range vs. < 10 mg/L was 1.03 (1.00, 1.07), and for ≥ 50 vs.< 10 mg/Lwas 1.06 (1.01, 1.11). Persons with low Ca and persons with low Mg also had higher GMR of FBG in the ≥10 and < 50 mg/L As group vs. <10 mg/L As. However, after Bonferroni correction no associations were significant. Conclusions: We did not detect an overall association between As and FBG. This may be due to exposure misclassification. It is possible that low groundwater K, Ca, or Mg exacerbated As toxicity to detectible levels despite exposure misclassification, but these could be false positives from multiple testing.