Associations of circulating calcium and 25-hydroxyvitamin D with glucose metabolism in pregnancy: a cross-sectional study in European and South Asian women

J Clin Endocrinol Metab. 2014 Mar;99(3):938-46. doi: 10.1210/jc.2013-2896. Epub 2014 Jan 1.

Abstract

Background: Vitamin D deficiency is thought to impair insulin action and glucose metabolism; however, previous studies have not examined ethnic differences or the influence of calcium and parathyroid hormone. We investigated this in a cohort of predominantly white European and south Asian women during pregnancy.

Methods: In this cross-sectional study from an urban population in northern England (53.8°N), 1467 women were recruited when undergoing glucose tolerance testing (75 g oral glucose tolerance test) at 26 weeks' gestation.

Results: Gestational diabetes mellitus (GDM) was diagnosed in 137 women (9.3%). Median 25-hydroxyvitamin D concentration for the study population was 9.3 ng/mL (interquartile range 5.2, 16.9) and was higher in European [15.2 ng/mL (10.7, 23.5)] than in south Asian women [5.9 ng/mL (3.9, 9.4), P < .001]. After appropriate adjustment for confounders, 25-hydroxyvitamin D showed a weak inverse association with fasting plasma glucose (FPG; mean difference 1.0% per 1 SD; the ratio of geometric means (RGM) 0.99, 95% confidence interval (CI) 0.98, 1.00), and PTH was weakly associated with FPG (RGM 1.01, 95% CI 1.00, 1.02), but neither was associated with fasting insulin, postchallenge glucose, or GDM. Serum calcium (albumin adjusted) was strongly associated with fasting insulin (RGM 1.06; 95% CI 1.03, 1.08), postchallenge glucose (RGM 1.03, 95% CI 1.01, 1.04), and GDM (odds ratio 1.33, 95% CI 1.06, 1.66) but not with FPG. Associations were similar in European and south Asian women.

Conclusions: These findings do not indicate any important association between vitamin D status and glucose tolerance in pregnancy. Relationships between circulating calcium and glucose metabolism warrant further investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Asian Continental Ancestry Group / statistics & numerical data
  • Blood Glucose / analysis
  • Blood Glucose / metabolism
  • Calcium / blood*
  • Cross-Sectional Studies
  • Diabetes, Gestational / blood
  • Diabetes, Gestational / diagnosis
  • Diabetes, Gestational / epidemiology*
  • England / epidemiology
  • European Continental Ancestry Group / statistics & numerical data
  • Female
  • Glucose / metabolism*
  • Glucose Tolerance Test
  • Humans
  • Pregnancy / metabolism*
  • Prevalence
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / diagnosis
  • Vitamin D Deficiency / epidemiology
  • Young Adult

Substances

  • Blood Glucose
  • Vitamin D
  • 25-hydroxyvitamin D
  • Glucose
  • Calcium