Interrelationships between chronic tension-type headache, musculoskeletal pain, and vitamin D deficiency: Is osteomalacia responsible for both headache and musculoskeletal pain?

Background: Headache, musculoskeletal symptoms, and vitamin D deficiency are common in the general population. However, the interrelations between these three have not been delineated in the literature. Materials and Methods: We retrospectively studied a consecutive series of patients who were diagnosed as having chronic tension-type headache (CTTH) and were subjected to the estimation of serum vitamin D levels. The subjects were divided into two groups according to serum 25(OH) D levels as normal (>20 ng/ml) or vitamin D deficient (<20 ng/ml). Results: We identified 71 such patients. Fifty-two patients (73%) had low serum 25(OH) D (<20 ng/dl). Eighty-three percent patients reported musculoskeletal pain. Fifty-two percent patients fulfilled the American College of Rheumatology criteria for chronic widespread pain. About 50% patients fulfilled the criteria for biochemical osteomalacia. Low serum 25(OH) D level (<20 ng/dl) was significantly associated with headache, musculoskeletal pain, and osteomalacia. Discussion: These suggest that both chronic musculoskeletal pain and chronic headache may be related to vitamin D deficiency. Musculoskeletal pain associated with vitamin D deficiency is usually explained by osteomalacia of bones. Therefore, we speculate a possibility of osteomalacia of the skull for the generation of headache (osteomalacic cephalalgia?). It further suggests that both musculoskeletal pain and headaches may be the part of the same disease spectrum in a subset of patients with vitamin D deficiency (or osteomalacia), and vitamin D deficiency may be an important cause of secondary CTTH.