Chronic tension-type headache with vitamin D deficiency: casual or causal association?

The prevalence of tension-type headache and vitamin D deficiency are both very high in the general population. The inter-relations between the two have not been explored in the literature. We report 8 patients with chronic tension-type headache and vitamin D deficiency (osteomalacia). All the patients responded poorly to conventional therapy for tension headache. The headache and osteomalacia of each of the 8 patients responded to vitamin D and calcium supplementation. The improvement in the headache was much earlier than the improvements in the symptom complex of osteomalacia. We also speculate on the possible mechanisms for headache in the patients with vitamin D deficiency.