Abstrakt

'Vitamin d-binding protein in somali women living in sweden was low and unaffected by treatment.'

Taye Demeke, Martin Gillstedt, Amra Osmancevic, Anne Lene Krogstad, H

Background: Vitamin D deficiency is common in immigrants. Whether vitamin D-binding protein (DBP) is genetically determined or influenced by external factors is not fully clarified. Objective: The aim was to study the influence of age, sex and ethnicity, and the effect of vitamin D treatment on serum DBP. Design: A randomized, placebo-controlled and a case-controlled study were performed. Somali women with skin type V (n = 113; <50 years), latitude 0-10°N, living in Sweden, latitude 57°N, were given 800 IU or 1600 IU cholecalciferol daily or UVB, and similar amounts of placebo (drops or Wood's lamp) during twelve weeks. Serum DBP and S-25(OH) D were monitored before and after treatment. A random population sample of men (n = 50) and women (n = 228; 65<50 years) with skin type II-III from the same region was used as controls. Results: Vitamin D deficiency was prevalent in 73 % of the Somali women and in 5% of the population of whom 0% in women <50 years. DBP was lower in Somali women than in Swedish women (both < 50 and ≥ 50 years; p<0.0001). DBP did not differ between men and women in the population and did not correlate with age, body weight or bone mineral density. DBP was positively correlated with S-25(OH) D in the control women (r=0.19; p=0.004). DBP did not increase with increasing S-25(OH) D levels during vitamin D treatment in Somali women. Conclusions: Vitamin D binding protein was related to vitamin D status but was independent of, or unaffected by, age, sex, body weight, bone status or vitamin D treatment.