The relationship between heavy metal exposure and type 2 diabetes: a large-scale retrospective cohort study using occupational health examinations

Objectives: To investigate the associations between heavy metal exposure and serum ferritin levels, physical measurements, and type 2 diabetes mellitus (DM).

Design: A retrospective cohort study.

Setting: Changwon, the location of this study, is a Korean representative industrial city. Data were obtained from medical check-ups between 2002 and 2018.

Participants: A total of 34,814 male subjects were included. Of them, 1,035 subjects with lead exposure, 200 subjects with cadmium exposure, and the 33,579 remaining were assigned to cohort A, cohort B, and the control cohort, respectively. Data including personal history of alcohol and smoking, age, height, weight, the follow-up duration, HbA1c, fasting blood sugar (FBS), ferritin levels, and lead and cadmium levels within one year after exposure were collected. 

Primary Outcome Measure: In subjects without diabetes, changes in FBS and HbA1c were analyzed through repeated tests at intervals of one year or longer after the oc...