Vitamin D status of middle-aged women at 65-71 degrees N in relation to dietary intake and exposure to ultraviolet radiation

Public Health Nutr. 2004 Apr;7(2):327-35. doi: 10.1079/PHN2003536.


Objective: To determine the vitamin D status of middle-aged women living in the Norwegian arctic and its relationship with vitamin D intake and exposure to ultraviolet (UV) radiation.

Design: Cross-sectional study.

Subjects and setting: This study is based on measurements of 25-hydroxyvitamin D (25(OH)D) levels in a sub-sample of the Norwegian component of the EPIC biological bank, which consists of blood samples from a random selection of participants in the Norwegian Women and Cancer Study. From November 2001 until June 2002, 309 blood samples were collected from a total of 443 invited middle-aged women (44-59 years) in northern Norway (65-71 degrees N) (crude response rate, 69.8%). Questionnaire data provided information on dietary sources of vitamin D and UV exposure.

Results: Median plasma 25(OH)D concentration for the whole group was 55.0 nmol l(-1) (range 8.1-142.8 nmol l(-1)). Vitamin D intake was a significant predictor of 25(OH)D status (P=0.0003). The time of the year when the blood sample was collected significantly predicted plasma 25(OH)D level (P=0.005). Levels of 25(OH)D were positively associated (P=0.0002) with estimated hours per day of exposure to UV-B radiation. Residing in northern Norway during the summer prior to blood sampling was negatively associated with 25(OH)D concentration (P=0.001). The prevalence of moderate hypovitaminosis D was highest in January-February, when a quarter of the participants had 25(OH)D concentrations < or =37.5 nmol l(-1).

Conclusions: Increased ingestion of marine food items that provide vitamin D should be promoted and further studies should be carried out to investigate vitamin D status in arctic populations in relation to both UV exposure and traditional food sources.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cross-Sectional Studies
  • Diet Surveys
  • Diet*
  • Female
  • Humans
  • Middle Aged
  • Norway / epidemiology
  • Nutritional Status
  • Seasons
  • Sunlight*
  • Surveys and Questionnaires
  • Ultraviolet Rays
  • Vitamin D / administration & dosage*
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood*
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / epidemiology*


  • Vitamin D
  • 25-hydroxyvitamin D