BERLIN – Vitamin D deficiency during the first trimester of pregnancy linked with a significantly increased risk for the development of gestational diabetes by the second trimester in a study of 655 pregnant women.
The study results also indicated that increased insulin resistance explained the significant association between vitamin D deficiency and an increased incidence of gestational diabetes, Marilyn Lacroix said at the annual meeting of the European Association for the Study of Diabetes.
Mitchel L. Zoler/IMNG Medical Media
Marilyn Lacroix
The analysis showed that for every standard-deviation decrease in blood levels of 25-hydroxyvitamin D identified during the first trimester, women had a statistically significant 40% increased rate of having gestational diabetes during their second trimester, after adjustment for age, season of blood sampling, use of vitamin D supplements, and degree of adiposity, reported Ms. Lacroix, an endocrinology researcher at Sherbrooke (Que.) University. In the population studied, a standard-deviation reduction in blood levels of vitamin D corresponded to a drop of 19 nmol/L.
The study included 655 pregnant women aged 18 or older at 6-13 weeks’ gestation with a singleton pregnancy and no history of diabetes or gestational diabetes, miscarriage, or alcohol or drug abuse. The researchers measured each woman’s blood level of 25-hydroxyvitamin D at gestational week 6-13, and then assessed each woman for diabetes at week 24-28. During the study, 54 of the women (8%) developed gestational diabetes.
The prevalence of first-trimester vitamin D deficiency – a blood level of less than 50 nmol/L – was 26% among the 601 women who were normoglycemic during the second trimester, and 37% among women who developed gestational diabetes by the second trimester.
The analysis also showed a significantly reduced average Matsuda index (Diabetes Care 1999;22:1462-70), as well as a significantly reduced insulin secretion sensitivity index (Diabetic Medicine 2009;26:1198-1203) among patients who went on to have gestational diabetes. These reductions suggest that insulin resistance forms the link between low vitamin D levels and incident gestational diabetes, Ms. Lacroix said.
Ms. Lacroix reported that she and her associates also had no relevant financial disclosures.