Vitamin D status in patients with musculoskeletal pain, fatigue and headache: A cross-sectional descriptive study in a multi-ethnic general practice in Norway

Objective. To investigate vitamin D levels in patients with non-specific musculoskeletal pain, headache, and fatigue. Design. A cross-sectional descriptive study. Setting. A health center in Oslo, Norway, with a multi-ethnic population. Subjects. A total of 572 patients referred by a general practitioner (GP) for an examination of hypovitaminosis D who reported musculoskeletal pain, headache, or fatigue. The patients' native countries were: Norway (n = 249), Europe, America, and South-East Asia (n = 83), and the Middle East, Africa, and South Asia (n = 240). Both genders and all ages were included. Main outcome measures. Vitamin D levels (25-hydroxyvitamin D) in nmol/L. Results. Hypovitaminosis D (25-hydroxyvitamin D = 50 nmol/L) was found in 58% of patients. One-third of ethnic Norwegians had hypovitaminosis D, while 83% of patients from the Middle East, Africa, and South Asia had hypovitaminosis D with minimal seasonal variation of levels. One in two women from these countries had a vitamin D level below 25 nmol/L. Mean vitamin D level was lower in patients with headaches compared with patients with other symptoms. Some 15% of patients with low (= 50 nmol/L) vitamin D levels reported headaches, compared with 5% of those with normal vitamin D levels. Conclusion. Our study shows a high prevalence of hypovitaminosis D in patients with non-specific musculoskeletal pain, headache, or fatigue for whom the GP had suspected a low vitamin D level. Hypovitaminosis D was not restricted to immigrant patients. These results indicate that GPs should maintain awareness of hypovitaminosis D and refer patients who report headaches, fatigue, and musculoskeletal pain with minimal sun exposure and a low dietary vitamin D intake for assessment.