Vitamin D deficiency in Northern Sweden : a cross-sectional study of an immigrant population at latitude 63° N, including an open partially randomized, controlled trial studying the effect of supplementation with different doses of cholecalciferol

• Main Author: Granlund, Lena
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Umeå universitet, Allmänmedicin 2018
• Subjects: vitamin D deficiency; 25-hydroxyvitamin D; cross-sectional study; immigrant; muscle strength; grip strength; anxiety; depression; health related quality of life; clinical trial; cholecalciferol; General Practice; Allmänmedicin; Northern Sweden
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-147575

Background: Vitamin D is a prohormone that plays a key role in the calcium and phosphate balance and has physiological functions throughout the entire body. Vitamin D is supplied by exposure to ultraviolet light or by food. The prevalence of vitamin D deficiency in immigrants in Northern Sweden was unknown. There was no consensus on how to define or treat vitamin D deficiency and no pure preparations of cholecalciferol available in Sweden. Aims: To study the prevalence and determinants of vitamin D deficiency in immigrants of African and Middle Eastern origin, to examine associations between vitamin D status and muscle strength, anxiety, depression and quality of life, and to determine the effect of supplementation with cholecalciferol on 25-hydroxyvitamin D3 [25(OH)D] and vitamin D status. Methods: 1. A cross-sectional, population-based study. Immigrants ages 25-65 from Africa and the Middle East (n=1306) living in Umeå, Sweden, were invited to participate. A total of 111 men and 106 women (16.5%) participated. 25(OH)D was measured by LC-MsMs. Anthropometry, medical, socioeconomic and lifestyle data was registered. Examinations: lower limb muscle strength, grip strength, HAD, health-related quality of life (QoL) 2. An open, partially randomized, controlled trial including immigrants from Africa or the Middle East, 192 subjects screened, 160 included and 147 completed the study. Intervention: cholecalciferol 12±2 weeks, 4 parallel groups; Group 1: 25(OH)D <25nmol/L: 10000 IU/d, Groups 2a and 2b: 25(OH)D 25-49 nmol/L: 2000 IU/d or 2000 IU/w, Group 3: 25(OH)D 50-74 nmol/L: 2000 IU/d. Results: Twelve percent of the immigrants showed a vitamin D deficiency (25(OH)D ˂25 nmol/L) and 73 % showed 25(OH)D ˂50 nmol/L. Vitamin D deficiency was twice as common in African immigrants as in the Middle Eastern group. Vitamin D deficiency was associated with intake of fatty fish less than once a week, absence of travel abroad and use of long-sleeved clothing in summer. Lower limb muscle strength was associated with 25(OH)D ...