Objective To study the association between metal exposure and risk of diabetes and prediabetes among Chinese workers exposed to metals.Methods We used data obtained from the baseline survey of the Jinchang Cohort Study of workers in Jinchang Industry,the largest nickel production company in China.A total of 42,122 workers ≥20 years of age were included in the study.A standardized,structured questionnaire was used to collect epidemiological information.Physical examinations and laboratory tests were conducted to evaluate the health status of the participants and to measure various biomarkers including blood sugar,lipids,and urinary metal concentrations.Logistic regression was used to study the association between occupational groups categorized according to the measured metal levels(office workers,low-level;mining/production workers,mid-level;and smelting/refining workers,high-level)and risk of diabetes and prediabetes.Results The overall prevalence of diabetes and prediabetes was 7.5% and 16.8%,respectively.The adjusted odds ratios for diabetes among mining/production workers and smelting/refining workers compared to office workers were 1.5(95% CI:1.3,1.7)and 3.8(95% CI:3.4,4.3),respectively.No association was observed between these occupational groups and prediabetes in this study.Conclusion Occupations associated with higher levels of metal exposure were associated with an increased risk of diabetes in this cohort.More studies are needed to confirm this observed association. Objective To study the association between metal exposure and risk of diabetes and prediabetes among Chinese workers exposed to metals. Methods We used data obtained from the baseline survey of the Jinchang Cohort Study of workers in Jinchang Industry, the largest nickel production company in China. A total of 42,122 workers ≥20 years of age were included in the study. A standardized, structured questionnaire was used to collect epidemiological information. Physical examinations and laboratory tests were conducted to evaluate the health status of the participants and to measure various biomarkers including blood sugar , lipids, and urinary metal concentrations. Logistic regression was used to study the association between occupational groups categorized according to the measured metal levels (office workers, low-level; mining / production workers, mid-level; and smelting / refining workers, high -level) and risk of diabetes and prediabetes. Results of overall accuracy of diabetes and prediabetes was 7.5 % and 16.8%, respectively. The adjusted odds ratios for diabetes among mining / production workers and smelting / refining workers compared to office workers were 1.5 (95% CI: 1.3,1.7) and 3.8 (95% CI: 3.4, 4.3) respectively. No association was observed between these occupational groups and prediabetes in this study. Conlusion Occupations associated with higher levels of metal exposure were associated with an increased risk of diabetes in this cohort. More studies are needed to confirm this observed association.