Vitamin D and pregnancy. Vitamin D deficiency and associations with gestational diabetes and neonatal body composition in a multi-ethnic population

Abstract

The overall goal of this thesis was to increase the knowledge about vitamin D status and vitamin D deficiency in pregnancy in a multi-ethnic population in Oslo, Norway. We used data from the STORK Groruddalen study, a population-based cohort of 823 healthy, pregnant women and their neonates. We found that approximately 80% of pregnant women from South Asia, Middle East and Africa had vitamin D deficiency in early pregnancy, compared with 20% of Western European women. The proportion of women using vitamin D supplementation was lower among ethnic minority women compared with Western European women, but both the proportion using supplements and mean 25(OH)D increased significantly after a simple recommendation for supplementation. After adjustments, we found no independent associations between 25(OH)D and gestational diabetes or other measures of glucose metabolism, or between 25(OH)D and birth weight or body composition of the newborn. Pregnant women from South Asia, Middle East and Africa had a high prevalence of vitamin D deficiency, but vitamin D deficiency could not explain the high prevalence of gestational diabetes or the lower birth weight found in these ethnic minority groups.