Multiple metals exposure, elevated blood glucose and dysglycemia among Chinese occupational workers.

AIMS: Exposure to metals may adversely affect cardiometabolic health. The aim of this study is to directly evaluate the roles of multiple metals exposure in glucose homeostasis, the dysfunction of which has been linked to diabetes and cardiovascular diseases (CVDs).

METHODS: We performed a cross-sectional analysis of baseline data from 464 metal-exposed workers who participated in a large prospective occupational study in China (Jinchang Cohort). The logistic regression model was used to evaluate the association between urinary metal levels and high fasting plasma glucose (high-FPG) (≥ 75th percentile) and dysglycemia.

RESULTS: Increasing levels of urinary nickel were prospectively associated with high-FPG: multivariable odds ratios (ORs) were 1.00 for the 1st quartile (lowest), 1.20 (95% confidence interval [CI]: 0.60-2.43) for the 2nd quartile, 1.64 (0.78-3.49) for the 3rd quartile and 3.17 (1.38-7.30) for the 4th quartile (highest) (P-trend=0.004). The positive associations were also observed between urinary zinc and high-FPG (4th vs. 1st quartile=2.71, 95%CI: 1.26-5.84, P-trend=0.01). Inverse associations between urinary cobalt and risk of high-FPG and dysglycemia were observed (P-trend <0.05). For dysglycemia, the positive trends of increasing levels of urinary nickel and zinc still remained, although urinary nickel was no longer statistically significant. A significant association between urinary arsenic and dysglycemia was also found. However, no associations were observed between urinary copper, cadmium, and risk of high-FPG or dysglycemia.

CONCLUSION: Multiple urinary metals, particularly arsenic, nickel, zinc, and cobalt, were associated with elevated blood glucose among Chinese occupational workers, supporting the notion that metal exposure plays a critical role in the development of diabetes.