Vitamin D status in North Greenland is influenced by diet and season: indicators of dermal 25-hydroxy vitamin D production north of the Arctic Circle

Vitamin D status, as measured by serum 25-hydroxy vitamin D (s-25OHD), is important to human health. Dermal 25OHD production depends on UVB light that is influenced by latitude. We aimed to identify factors important to the production of s-25OHD in Arctic people and investigated subjects living in the town of Ilulissat and the settlement of Saqqaq in North Greenland (70°N) during the four seasons. Participants were enrolled with a balanced representation of non-Inuit and Inuit in Ilulissat and Inuit in Saqqaq, men and women, aged 30-39 and 40-49 years. Supplement use, hours spent outdoors and other lifestyle factors were determined by questionnaires. Scores of traditional Inuit food intake were computed from a FFQ at inclusion, and frequencies of intake were recorded at each visit. s-25OHD concentration was measured. There were sixty-four Inuit and thirty-three non-Inuit participants. Inuit food score