title: Evaluation of sun holiday, diet habits, origin and other factors as determinants of vitamin D status in Swedish primary health care patients: a cross-sectional study with regression analysis of ethnic Swedish and immigrant women.
abstract: BACKGROUND
  Determinants of vitamin D status measured as 25-OH-vitamin D in blood are exposure to sunlight and intake of vitamin D through food and supplements. It is unclear how large the contributions are from these determinants in Swedish primary care patients, considering the low radiation of UVB in Sweden and the fortification of some foods. Asian and African immigrants in Norway and Denmark have been found to have very low levels, but it is not clear whether the same applies to Swedish patients. The purpose of our study was to identify contributors to vitamin D status in Swedish women attending a primary health care centre at latitude 60°N in Sweden.
  
  
  METHODS
  In this cross-sectional, observational study, 61 female patients were consecutively recruited between January and March 2009, irrespective of reason for attending the clinic. The women were interviewed about their sun habits, smoking, education and food intake at a personal appointment and blood samples were drawn for measurements of vitamin D and calcium concentrations.
  
  
  RESULTS
  Plasma concentration of 25-OH-vitamin D below 25 nmol/L was found in 61% (19/31) of immigrant and 7% (2/30) of native women. Multivariate analysis showed that reported sun holiday of one week during the last year at latitude below 40°N with the purpose of sun-bathing and native origin, were significantly, independently and positively associated with 25-OH-vitamin D concentrations in plasma with the strongest association for sun holiday during the past year.
  
  
  CONCLUSIONS
  Vitamin D deficiency was common among the women in the present study, with sun holiday and origin as main determinants of 25-OH-vitamin D concentrations in plasma. Given a negative effect on health this would imply needs for vitamin D treatment particularly in women with immigrant background who have moved from lower to higher latitudes.
authors.affiliation: Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine unit, Uppsala University, Box 564, Uppsala SE-751 22, Sweden. anne.bjork@pubcare.uu.se.
authors.forename: Anne
authors.initials: A
authors.lastname: Björk
authors.forename: Åsa
authors.initials: Å
authors.lastname: Andersson
authors.forename: Gunnar
authors.initials: G
authors.lastname: Johansson
authors.forename: Karin
authors.initials: K
authors.lastname: Björkegren
authors.forename: Annika
authors.initials: A
authors.lastname: Bardel
authors.forename: Per
authors.initials: P
authors.lastname: Kristiansson
mesh_terms: D000328:Adult; D000351:Africa, Eastern / Q000208:ethnology; D001136:Armenia / Q000208:ethnology; D001459:Bangladesh / Q000208:ethnology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D019587:Dietary Supplements / Q000706:statistics & numerical data; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data; D005247:Feeding Behavior; D005260:Female; D006693:Holidays / Q000706:statistics & numerical data; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D008877:Middle East / Q000208:ethnology; D015999:Multivariate Analysis; D011320:Primary Health Care; D011481:Protective Clothing / Q000706:statistics & numerical data; D012907:Smoking / Q000453:epidemiology; D013472:Sunlight; D013473:Sunscreening Agents / Q000627:therapeutic use; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000208:ethnology*; D044465:White People / Q000706:statistics & numerical data
chemical_list: D013473:Sunscreening Agents; D014807:Vitamin D; C104450:25-hydroxyvitamin D