Vitamin D insufficiency linked to insulin resistance among pregnant women

Vitamin D insufficiency may promote insulin resistance in the third trimester of pregnancy, particularly in the presence of excessive gestational weight gain, a study reports.

The study used data from the MINA-Brazil Study and included 444 pregnant women enrolled in antenatal care and had complete data on 25(OH)D3, weight gain, insulin, and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR).

Researchers estimated predicted probabilities for insulin resistance (HOMA-IR >2.71) according to excessive gestational weight gain. They used quantile and logistic regression models, with adjustment for sociodemographic, obstetric, and lifestyle characteristics, as well as gestational age and seasonality at outcome assessment.

Results revealed a significant association between persistent vitamin D insufficiency and increasing insulin concentrations (p=0.04 for trend). Pregnant women with vs without vitamin D insufficiency in the second or third trimester had an 83-percent higher likelihood of developing insulin resistance (odds ratio, 1.83, 95 percent confidence interval [CI], 1.03–3.27). Of note, this association was significantly modified by gestational weight gain (p=0.038).

Among women without excessive gestational weight gain, the predicted probabilities for insulin resistance were 0.345 (95 percent CI, 0.224–0.467) for those with persistent vitamin D insufficiency and 0.134 (95 percent CI, 0.046–0.221) for those who were vitamin D sufficient.

Meanwhile, probabilities for insulin resistance did not vary according to vitamin D status among participants with excessive gestational weight gain.