title: Determinants of vitamin D status in fair-skinned women of childbearing age at northern latitudes.
abstract: OBJECTIVE
  Poor vitamin D status during pregnancy has been associated with unfavorable outcomes for mother and child. Thus, adequate vitamin D status in women of childbearing age may be important. The aim of this study is to investigate the determinants of 25-hydroxyvitamin D (25(OH)D) serum concentrations in women of childbearing age living in Sweden, at latitude 57-58° north.
  
  
  METHODS
  Eighty four non-pregnant, non-lactating, healthy, fair-skinned women aged between 25-40 years were included. All subjects provided blood samples, four day food records and answered questionnaires about sun exposure and lifestyle. Total serum 25(OH)D was analyzed using Roche Cobas® electrochemoluminiescent immunoassay.
  
  
  RESULTS
  Mean 25(OH)D was 65.8±19.9 nmol/l and 23% of the subjects had concentrations <50 nmol/l. Only 1% had concentrations <25 nmol/l. Determinants of 25(OH)D concentrations were recent sunbed use, recent travel to southern latitude, season, estrogen contraceptive use and use of supplementary vitamin D (R(2) = 0.27).
  
  
  CONCLUSIONS
  Every fifth woman had 25(OH)D concentrations <50 nmol/l. About 30% of the variation in vitamin D status was explained by sun exposure, use of vitamin D supplements and use of estrogen contraceptives. Cutaneous vitamin D synthesis seems to be a major contributor to vitamin D status, even at northern latitudes. Thus, recommendations on safe UV-B exposure could be beneficial for vitamin D status.
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Linnea
authors.initials: L
authors.lastname: Hedlund
authors.forename: Petra
authors.initials: P
authors.lastname: Brembeck
authors.forename: Hanna
authors.initials: H
authors.lastname: Olausson
mesh_terms: D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008019:Life Style; D011247:Pregnancy; D012016:Reference Values; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D