Previous published reports from Hong Kong have suggested iron markers may be increased in mothers with gestational diabetes. We examined this in our predominantly Caucasian population. Serum iron, ferritin and total iron saturation index (TSI)) where measured in sixty mothers with gestational diabetes compared to controls matched for age and parity. All participants were Caucasian. The study had LEC approval. Gestational diabetes was defined as glucose of 7.8 mmol/l or more in the 2 h sample of a 75 g oral glucose tolerance test (GTT), performed at 2831 weeks gestation. The iron markers were measured in fasting blood samples collected at the time of the GTT.
Contrary to the earlier published reports, our study failed to demonstrate a significant difference in iron markers in gestational diabetes mothers compared to controls. The differences in mean values (subjectscontrols) were as follows: ferritin 2 μg/l (−4.78.0) P 0.55; iron −1.8 umol/l (−3.90.4) P 0.11; TSI −0.03 (−0.080.02). (P indicated for two sided t-test. Brackets indicate 95% confidence intervals). In addition, the slope of the regression lines for each analyte compared to 2 h glucose were not significantly different to zero: ferritin P 0.86, iron P 0.34, TSI P 0.17 (when subjects and controls combined). It has been suggested that a higher prevalence of hepatitis B surface antigen in the Honk Kong gestational diabetes mothers may have been responsible for their observed association of iron markers and gestational diabetes. In our study population subjects and controls were all negative for the hepatitis B surface antigen. Furthermore in our study CRP (a marker of inflammation) and ALT (a liver marker) were not significantly different in the gestational diabetes mothers and controls, nor did either CRP or ALT correlate with either ferritin or GTT 2 h glucose levels.