Relation between cadmium exposure and gestational diabetes mellitus

Background: Cadmium (Cd) has been associated with type 2 diabetes in general population. However, the role of Cd in the occurrence of Gestational diabetes mellitus (GDM) remains unclear. Objectives: Our study was aimed at investigating whether Cd exposure during pregnancy was associated with increased risk of GDM. Methods: Cd concentrations were measured in urine samples from 6837 pregnant women in Wuhan, China, from 2012 to 2014. A modified Poisson model with a robust error variance was used to examine the association of GDM with continuous natural logarithm (ln) transformed urinary Cd or quartiles of urinary Cd levels. Results: For about 3-fold increase in Cd concentrations, there were 16% [relative risk (RR) = 1.16; 95% confidence interval (CI): 1.03, 1.33] increase in risk of GDM. Compared with women in the lowest quartile of urinary Cd levels, women in the highest quartile had 1.30 higher risk of GDM [95% CI: 1.05, 1.61; p-trend < 0.05]. Further analyses indicated overweight/obese women with higher urinary Cd levels had significantly higher risk of GDM, compared with women in the reference category of lowest quartile of Cd and normal pre-pregnancy body mass index [RR = 2.71; 95% CI: 1.81, 4.07]. Conclusions: Our study presented a significantly positive association between urinary Cd levels and risk of GDM, supporting the hypothesis that environmental exposure to Cd may contribute to the development of GDM.