Effect of Vitamin D Supplementation on Muscular Strength, Musculoskeletal Pain and Headache

Vitamin D deficiency is a widespread public health problem among immigrants from non-Western countries in Norway. As a background for preventive strategies it is important to have best possible knowledge about health consequences of poor vitamin D status, and in this respect much is lacking.

The investigators will aim to study the effect of vitamin D supplementation on muscular strength , musculoskeletal pain and headache among non-western immigrants in Norway with background from Middle East, Africa and South Asia. In addition the intervention gives us the opportunity to study the effect of vitamin D on indicators of other important health issues including anemia, diabetes , lipids, inflammation, metabolism and bone health. The study will also contribute with insight on how to achieve a high compliance. This is of interest in a broader context as poor compliance has been experienced as a problem in primary health care among immigrants with poor vitamin D status.

The study is a randomized, double blinded, placebo-controlled trial which compares two doses of vitamin D supplements, 400 IU and 1000 IU, with placebo and the tablets will be taken daily in a period of 4 months. Three muscle strength tests will be used, and they will be performed before and after the intervention: Counter movement jumps, Chair rising and Handgrip. Level and location of musculoskeletal pain and headache will be recorded at baseline and at end of the study.

A blood sample will be collected from the study subjects at baseline and after 4 months. The level of vitamin D and markers of anemia, metabolism and bone turnover, inflammation, diabetes, lipids and kidney function will be measured.

Inclusion criteria

• Male and female between 18 - 50 years old
• Immigrants with background from Middle East, Africa and South Asia.

Exclusion criteria

• Daily use of vitamin D supplementation and frequently use of artificial UV light exposure.
• Pregnancy
• Malabsorptive disorders
• Fracture in the leg /arm within the preceding 6 months. Known osteoporosis
• Tuberculosis, sarcoidosis, cancer, kidney dysfunction, liver dysfunction and history of kidney stone.
• Regular use of medication that interfere with vitamin D/bone metabolism, such as glucocorticoids, diuretics, lithium, antiepileptics, bisphosphonates,
• Regular use of strong pain killers.
• Medication for diabetes