title: Vitamin D deficiency in UK South Asian Women of childbearing age: a comparative longitudinal investigation with UK Caucasian women.
abstract: CONCLUSIONS
  This is the first 1-year longitudinal study which assesses vitamin D deficiency in young UK-dwelling South Asian women. The findings are that vitamin D deficiency is extremely common in this group of women and that it persists all year around, representing a significant public health concern.
  
  
  BACKGROUND
  There is a lack of longitudinal data assessing seasonal variation in vitamin D status in young South Asian women living in northern latitudes. Studies of postmenopausal South Asian women suggest a lack of seasonal change in 25-hydroxy vitamin D [25(OH)D], although it is unclear whether this is prevalent among premenopausal South Asians. We aimed to evaluate, longitudinally, seasonal changes in 25(OH)D and prevalence of vitamin D deficiency in young UK-dwelling South Asian women as compared with Caucasians. We also aimed to establish the relative contributions of dietary vitamin D and sun exposure in explaining serum 25(OH)D.
  
  
  METHODS
  This is a 1-year prospective cohort study assessing South Asian (n = 35) and Caucasian (n = 105) premenopausal women living in Surrey, UK (51° N), aged 20-55 years. The main outcome measured was serum 25(OH)D concentration. Secondary outcomes were serum parathyroid hormone, self-reported dietary vitamin D intake and UVB exposure by personal dosimetry.
  
  
  RESULTS
  Serum 25(OH)D <25 nmol/L was highly prevalent in South Asians in the winter (81 %) and autumn (79.2 %). Deficient status (below 50 nmol/L) was common in Caucasian women. Multi-level modelling suggested that, in comparison to sun exposure (1.59, 95 %CI = 0.83-2.35), dietary intake of vitamin D had no impact on 25(OH)D levels (-0.08, 95 %CI = -1.39 to 1.23).
  
  
  CONCLUSIONS
  Year-round vitamin D deficiency was extremely common in South Asian women. These findings pose great health threats regarding the adverse effects of vitamin D deficiency in pregnancy and warrant urgent vitamin D public health policy and action.
authors.affiliation: Department of Nutrition and Metabolism, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK. A.Darling@surrey.ac.uk
authors.forename: A L
authors.initials: AL
authors.lastname: Darling
authors.forename: K H
authors.initials: KH
authors.lastname: Hart
authors.forename: H M
authors.initials: HM
authors.lastname: Macdonald
authors.forename: K
authors.initials: K
authors.lastname: Horton
authors.forename: A R
authors.initials: AR
authors.lastname: Kang'ombe
authors.forename: J L
authors.initials: JL
authors.lastname: Berry
authors.forename: S A
authors.initials: SA
authors.lastname: Lanham-New
mesh_terms: D000328:Adult; D044466:Asian People / Q000706:statistics & numerical data*; D004032:Diet / Q000208:ethnology / Q000706:statistics & numerical data; D004739:England / Q000453:epidemiology; D004781:Environmental Exposure / Q000032:analysis; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D017697:Premenopause / Q000097:blood; D015995:Prevalence; D012621:Seasons; D013472:Sunlight; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000208:ethnology*; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D