An analysis of data from the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) found that middle-aged men with low serum 25-hydroxyvitamin D (25(OH)D) concentrations had a markedly higher risk of frequent headache. Results were published January 7 ahead of print in Scientific Reports.1
In an interview, lead investigator Jyrki K. Virtanen PhD told Clinical Pain Advisor that small studies had previously shown a link between low serum vitamin D levels and headache. “Therefore, we wanted to investigate in a much larger study in a Nordic country whether low vitamin D exposure could be associated with the risk of headache.” Dr Virtanen commented that in Nordic countries such as Finland, skin is able to produce vitamin D only during the few summer months and the body’s vitamin D stores can dip quite low during winter without adequate intake from foods or supplements.
The Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD), initially created to study the relationship between various health determinants and cardiovascular outcomes, is a population-based prospective cohort study that enrolled 2682 middle-aged (42 to 60 years of age) men from eastern Finland.2 The data for the recent headache study were originally collected from 1984 to 1989. Participants who reported weekly or daily headache via a questionnaire were classified as having frequent headache. Serum 25(OH)D levels were assessed using fasting venous blood samples obtained at baseline. Ultimately, 2601 men whose records included serum 25(OH)D levels and headache data were included in the headache study.
Results showed that 250 men in the cohort (9.6%) reported frequent headache. After multivariable adjustments, participants in the lowest serum 25(OH)D quartile had 116% higher odds for frequent headache (OR 2.16; 95% CI 1.49–3.13) than those in the highest quartile.
Summary and Clinical Applicability
Dr Virtanen stated that research is necessary to determine whether vitamin D supplementation can help to reduce headaches and migraine. “We are running the Finnish Vitamin D Trial, where 2500 men and women 60 years and older take vitamin D supplements (40 or 80 µg/day, which is 1600/3200 IU/day) for 5 years,” he told Clinical Pain Advisor. “Among other chronic diseases, one of our goals is to investigate the effects of vitamin D supplementation on pain.”
Whether or not the association with headache is ultimately proven, Dr Virtanen recommends that people in Nordic countries make sure that they get sufficient vitamin D from food or from vitamin D supplements to prevent vitamin D levels from dropping too low during the winter.
Limitations & Disclosures
Dr Virtanen told Clinical Pain Advisor that this observational study did not prove that low serum vitamin D caused frequent headaches. “For example, those who suffer from frequent headaches may be less likely to spend time outdoors and would thus be less exposed to the UVB light,” he noted. “Also, the higher risk of frequent headaches was observed only among those in the lowest serum vitamin D category (<29 nmol/L or 12 ng/ml), so it is possible that only quite low vitamin D levels have an impact on headaches.”
The authors declared no competing financial interests. Investigator R. Giniatullin was supported by a research grant from the Academy of Finland (grant #277442). The other authors did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
- Virtanen JK, Giniatullin R, Mäntyselkä P, et al. Low serum 25-hydroxyvitamin D is associated with higher risk of frequent headache in middle-aged and older men. Sci Rep. 2017;7:39697. doi:10.1038/srep39697.
- Jussi K. Kuopio Ischemic Heart Disease Risk Factor Study. In: Gellman M, Turner JR, eds. Encyclopedia of Behavioral Medicine. New York, NY: Springer New York; 2016:1-2. http://link.springer.com/10.1007/978-1-4614-6439-6_328-2. Accessed January 12, 2017.