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Elevated maternal iron levels increases gestational diabetes risk
Pregnant women with elevated serum ferritin levels are at increased risk for developing gestational diabetes, according to research in Diabetic Medicine.
Amina Z. Khambalia, PhD, a research fellow and epidemiologist at the Kolling Institute of Medical Research, University of Sydney, and colleagues analyzed ferritin, soluble transferrin receptor and C-reactive protein levels in 3,776 Australian women, measured during their first trimester of pregnancy between January and October 2007, and linked the measurements to birth and hospital records for data on maternal characteristics and gestational diabetes diagnoses. Researchers used multivariate logistic regression analysis to assess the link between iron biomarkers and gestational diabetes. In a separate systematic review and meta-analysis, researchers examined all studies published between 1995 and July 2015 that assessed the association between iron levels and gestational diabetes with an appropriate comparison group (n = 19).
Within the cohort, 129 women ( 3.4% ) developed gestatio nal diabetes; these women had higher mean serum ferritin concentrations vs. women who did not develop gestational diabetes (32.8 µ g/L vs. 24.8 µ g/L; P = .001), and were less likely to have iron deficiency (9.3% vs. 19.9%; P = .003). Researchers found no between-group differences in mean soluble transferrin receptor levels (15.7 nmol/L vs. 15.1 nmol/L; P = .11).
Researchers found an increased risk for gestational diabetes when ferritin was examined as a continuous variable (adjusted OR = 1.41; 95% CI, 1.11-1.78), but no association between soluble transferrin receptor levels and gestational diabetes.
In meta-analysis, two randomized controlled trials assessing iron supplement use in early pregnancy found no association with the risk for gestational diabetes; two cohort studies found a significant association between dietary heme iron intake and gestational diabetes, but not for non-heme iron. In a pooled analysis of case-control studies examining the association between high serum iron levels and gestational diabetes, women with gestational diabetes had higher concentrations of serum ferritin and serum iron.
“A review of the literature to date indicates that increased risk of gestational diabetes does not result from short exposures to iron supplements during pregnancy, but is associated with higher intakes of dietary [heme] iron during the preconception and early pregnancy period,” the researchers wrote. “Further studies are warranted that better characterize iron’s role in the patho-physiological pathways that lead to gestational diabetes, that measure and compare multiple iron biomarkers in combination with dietary and supplemental sources of iron, and that identify high-risk populations for intervention studies.” – by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.