Whitelaw, D.Scally, A.Tuffnell, D.Davies, T.Fraser, W.Bhopal, R.Wright, J.Lawlor, D.2018-05-112018-05-112014Journal of Clinical Endocrinology and Metabolism (JCEM), 2014; 99(3):938-9460021-972X1945-7197http://hdl.handle.net/2440/112034Vitamin 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.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.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.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.en© 2014 by The Endocrine SocietyHumansDiabetes, GestationalVitamin D DeficiencyCalciumGlucoseBlood GlucoseVitamin DGlucose Tolerance TestPrevalenceCross-Sectional StudiesPregnancyAdultAsian Continental Ancestry GroupEuropean Continental Ancestry GroupEnglandFemaleYoung AdultJournal article003004272710.1210/jc.2013-28960003334616000562-s2.0-84895801127232768Lawlor, D. [0000-0002-6793-2262]