High maternal iron status, dietary iron intake and iron supplement use in pregnancy and risk of gestational diabetes mellitus: a prospective study and systematic review.

High iron measured using dietary intake and biomarkers is associated with Type 2 diabetes. It is uncertain whether a similar association exists for gestational diabetes mellitus. The aim of this systematic review was to conduct a cohort study examining first trimester body iron stores and subsequent risk of gestational diabetes, and to include these findings in a systematic review of all studies examining the association between maternal iron status, iron intake (dietary and supplemental) and the risk of gestational diabetes. Serum samples from women with first trimester screening were linked to birth and hospital records for data on maternal characteristics and gestational diabetes diagnosis. Blood was analysed for ferritin, soluble transferrin receptor and C-reactive protein. Associations between iron biomarkers and gestational diabetes were assessed using multivariate logistic regression. A systematic review and meta-analysis, registered with PROSPERO (CRD42014013663) included studies of all designs published in English from January 1995 to July 2015 that examined the association between iron and gestational diabetes and included an appropriate comparison group. Of 3776 women, 3.4% subsequently developed gestational diabetes. Adjusted analyses found increased odds of gestational diabetes for ferritin (OR 1.41; 95% CI 1.11, 1.78), but not for soluble transferrin receptor (OR 1.00; 95% CI 0.97, 1.03) per unit increase of the biomarker. Two trials of iron supplementation found no association with gestational diabetes. Increased risk of gestational diabetes was associated with higher levels of ferritin and serum iron and dietary haem iron intakes. Increased risk of gestational diabetes among women with high serum ferritin and iron levels and dietary haem iron intakes warrants further investigation.

Khambalia AZ ，Aimone A ，Nagubandi P ，Roberts CL ，McElduff A ，Morris JM ，Powell KL ，Tasevski V ，Nassar N ... -  《-》

Iron deficiency in early pregnancy using serum ferritin and soluble transferrin receptor concentrations are associated with pregnancy and birth outcomes.

Khambalia AZ ，Collins CE ，Roberts CL ，Morris JM ，Powell KL ，Tasevski V ，Nassar N ... -  《-》

A longitudinal study of iron status during pregnancy and the risk of gestational diabetes: findings from a prospective, multiracial cohort.

Rawal S ，Hinkle SN ，Bao W ，Zhu Y ，Grewal J ，Albert PS ，Weir NL ，Tsai MY ，Zhang C ... -  《-》

Iron Status and Gestational Diabetes-A Meta-Analysis.

Kataria Y ，Wu Y ，Horskjær PH ，Mandrup-Poulsen T ，Ellervik C ... -  《Nutrients》

Plasma Concentrations of Ferritin in Early Pregnancy Are Associated with Risk of Gestational Diabetes Mellitus in Women in the Danish National Birth Cohort.

Evidence from experimental studies has demonstrated that higher than normal iron concentrations can lead to pancreatic β cell dysfunction and impaired glucose metabolism. Studies on body iron stores in early pregnancy and subsequent gestational diabetes mellitus (GDM) risk are sparse. Our objective was to determine whether biomarkers of body iron stores measured in early pregnancy are associated with GDM risk. A case-control study of 350 GDM cases and 349 non-GDM controls was conducted in participants from the Danish National Birth Cohort. Blood was collected at a mean ± SD gestational age of 9.4 ± 3.2 wk. Plasma biomarkers of iron stores, including ferritin and soluble transferrin receptor (sTfR), were measured. Logistic regression was used to estimate the OR of GDM associated with quintiles of plasma biomarkers of body iron stores, controlling for maternal age, family history of diabetes, exercise in pregnancy, parity, and prepregnancy body mass index (BMI). Cases were older (mean ± SD age: 32.2 ± 4.3 compared with 29.9 ± 4.2 y) and had a higher BMI (in kg/m(2); mean ± SD: 28.7 ± 6.0 compared with 24.1 ± 4.6) than controls. Plasma concentrations of both ferritin and sTfR in early pregnancy were significantly higher in GDM cases than in controls [means ± SDs: 80.6 ± 56.0 compared with 71.8 ± 50.1 μg/L (P = 0.03) and 1.5 ± 0.7 compared with 1.4 ± 0.6 mg/L (P = 0.002) for ferritin and sTfR, respectively]. Ferritin was positively and significantly associated with GDM risk even after adjustment for major risk factors of GDM, including prepregnancy BMI. ORs across increasing quintiles of ferritin were 1.00 (reference), 1.25 (95% CI: 0.70, 2.22), 1.89 (95% CI: 1.06, 3.37), 0.82 (95% CI: 0.46, 1.48), and 2.34 (95% CI: 1.30, 4.21) (P-linear trend = 0.02). These findings suggest that plasma ferritin measured in early pregnancy is significantly and positively associated with GDM risk.

Bowers KA ，Olsen SF ，Bao W ，Halldorsson TI ，Strøm M ，Zhang C ... -  《-》