Headache may be related to vitamin D deficiency
© Springer-Verlag 2010
Received: 15 June 2010
Accepted: 21 June 2010
Published: 3 July 2010
We appreciate the comments of Zhang and colleagues and agree that our review is not sufficient enough to suggest that vitamin D insufficiency causes headache. The purpose of our review was to delineate a relationship of headache prevalence with the latitude, and we noted a significant relation; the prevalence of headache increased with increasing latitude . The geographical variation of a disease could be due to environmental and genetic factors, and a positive relation with latitude hints towards a role of vitamin D. However, as discussed in the article, a number of confounding factors exist, and a possibility of coincidence exists.
In medical science, a hypothesis is proposed to explain some observable facts. Leedy and Ormrod  define hypothesis as “a logical supposition, a reasonable guess, and an educated conjecture”. A hypothesis is a speculative idea that has yet to be explored. It may be important as it guides the research. As far as vitamin D is concerned, a causal association of vitamin D deficiency with various diseases was initially suggested by some epidemiological and ecological observations. Later on, many of these disorders were confirmed by various studies. The association of vitamin D with colon cancer is the best example for it . Even a role of vitamin D in the pathogenesis of multiple sclerosis and schizophrenia was first suggested on epidemiological evidences, including a positive relation with latitude [3, 4].
We agree with the authors that observational studies to find decreased levels of serum vitamin D levels in patients with headache and placebo-controlled studies to observe the therapeutic effects of vitamin D in headache are required to confirm our observations. However, at present, a few case series of vitamin D responsive headaches , a few observational studies showing low serum vitamin D levels in patients with headache , high prevalence of vitamin D insufficiency in patients with generalized muscle pain syndrome and depression (two most common co-morbid conditions with headache disorders) , and a high concentration of vitamin D receptor and vitamin D binding protein in the hypothalamus somewhat suggest that an inter-relation exists between vitamin D and headache .
Conflict of interest
- Prakash S, Mehta NC, Dabhi AS, Lakhani O, Khilari M, Shah ND (2010) The prevalence of headache may be related with the latitude: a possible role of vitamin D insufficiency? J Headache Pain (in press)Google Scholar
- Leedy PD, Ormrod JE (2001) Practical research: planning and design, 7th edn. Merrill Prentice Hall, Upper Saddle RiverGoogle Scholar
- Grant WB (2006) Epidemiology of disease risks in relation to vitamin D insufficiency. Prog Biophys Mol Biol 92(1):65–79, 10.1016/j.pbiomolbio.2006.02.013, 1:CAS:528:DC%2BD28XlsFKrsbk%3D, 16546242View ArticlePubMedGoogle Scholar
- McGrath J (2010) Is it time to trial vitamin D supplements for the prevention of schizophrenia? Acta Psychiatr Scand 121(5):321–324, 10.1111/j.1600-0447.2010.01551.x, 20525021View ArticlePubMedGoogle Scholar
- Prakash S, Shah ND (2009) Chronic tension-type headache with vitamin D deficiency: casual or causal association? Headache 49(8):1214–1222, 10.1111/j.1526-4610.2009.01483.x, 19619241View ArticlePubMedGoogle Scholar
- Wheeler SD (2008) Vitamin D deficiency in chronic migraine. Headache 48(S1):S52–S53Google Scholar