An Evaluation of Speciated Plasma Arsenicals as Potential Biomarkers of Arsenic Exposure and Arsenic-Associated Diabetes in Individuals Living in Zimapan and Lagunera, Mexico

摘要

Background: Exposure to inorganic arsenic (iAs) remains a public health issue. Typically, three major forms of arsenic are measured in urine as biomarkers of iAs exposure, namely, iAs, and its metabolites, monomethylated arsenic (MMAs) and dimethylated arsenic (DMAs). This study is among the first to examine speciated plasma arsenicals as biomarkers of iAs exposure and iAs-associated disease, namely, diabetes mellitus (DM). Methods: Drinking water and plasma samples were collected from participants in the Zimapan and Lagunera cohort (N = 258). The relationships between drinking water iAs and plasma arsenicals were examined using both spearman correlations and multivariable linear regression models. Multivariable linear and logistic regression models were used to estimate the mean difference (95% CI) for the relationship between plasma arsenicals and diabetes indicators and the odds ratio (95% CI) for the relationship between plasma arsenicals and DM. Results: Plasma arsenicals were associated with drinking water iAs, with spearman correlation coefficients of 0.45 for P-MMAs, 0.48 for P-DMAs and 0.41 for total arsenic (P-tAs; p < 0.0001). After adjusting for potential confounders, there were significant associations between log-transformed plasma arsenic and log-transformed diabetes indicators. Specifically, an interquartile range (IQR) increase in P-iAs was associated with fasting plasma insulin (0.089 (95% CI: 0.025, 0.153)), insulin resistance (HOMA-IR; 0.084 (95% CI: 0.017, 0.152)), and beta cell function (HOMA-B; 0.133 (95% CI: 0.007, 0.259)). Plasma arsenicals were not associated with the odds of DM. Conclusions: Speciated plasma arsenicals were associated with drinking water iAs, suggesting that they may serve as biomarkers of iAs exposure. Increases in fasting plasma insulin, HOMA-IR, and HOMA-B in the absence of changes in glycemia, indicate that plasma arsenic may be related to subclinical changes in pancreatic beta cell function that underlie DM development.