Association between plasma concentration of copper and gestational diabetes mellitus

Emerging findings have raised concerns about significant associations between excessive copper (Cu) and abnormal glucose metabolism. Nevertheless, related researches on the relationship of Cu concentration and gestational diabetes mellitus (GDM) are limited. The objective of this study was to determine whether plasma Cu concentration is associated with GDM.

A case-control study of 248 cases of GDM and 248 age-, parity- and gestational age-matched controls was conducted in Wuhan, China between August 2012 and April 2015. Fasting blood samples of participants were collected at the time of GDM screening (≥24 weeks of gestation). Plasma Cu concentrations were detected by inductively coupled plasma mass spectrometry. The strength of the association of plasma Cu with GDM odds was evaluated by odds ratios (ORs) with 95% confidence intervals (CIs) from conditional logistic regression. Partial Spearman or Pearson correlation coefficients were calculated to estimate the interrelationship between plasma Cu and the risk factors of GDM.

Plasma Cu concentrations in the GDM group (mean ± SD: 1960.24 ± 391.98 μg/L) were higher than in the control group (mean ± SD: 1842.43 ± 387.09 μg/L) (P = 0.001). After adjustment for possible confounders, the ORs (95% CIs) of GDM across increasing quartiles of plasma Cu levels were 1.00 (referent), 1.79 (0.90-3.55), 2.72 (1.35-5.48) and 2.91 (1.48-5.75), respectively; the OR (95% CI) of GDM was 1.33 (1.06-1.67) for each standard deviation increment of plasma Cu. Moreover, Cu concentrations were positively associated with fasting plasma glucose, 1-h post-glucose load and 2-h post-glucose load (all P < 0.05).

The present study indicated a significantly increased odds of GDM in association with higher concentrations of plasma Cu. Prospective cohort studies in other populations are needed to confirm our findings.