Objectives To examine the longitudinal relationship between cardiovascular fitness in young adult men and future risk of migraine and to estimate eventual differential effects among categories of body mass index (BMI) and blood pressure.
Design National, prospective, population-based cohort study.
Setting Sweden 1968–2014.
Participants 18-year-old Swedish men (n=1 819 828) who underwent mandatory military conscription examinations during the years 1968–2005.
Primary and secondary outcomes The primary outcome was the first dispensation of prescribed migraine-specific medication, identified using the Swedish Prescribed Drug Register. The secondary outcome was documented migraine diagnosis from the Swedish National Hospital Register.
Results During follow-up, 22 533 men filled a prescription for migraine-specific medication. After confounding adjustment, compared with high cardiovascular fitness, low and medium fitness increased the risk of migraine-specific medication (risk ratio (RR)low: 1.29, 95% CI 1.24 to 1.35; population attributable fraction: 3.6%, 95% CI 1.7% to 5.3% and RRmedium: 1.15, 95% CI 1.12 to 1.19; population attributable fraction: 8.0%, 95% CI 4.0% to 11.7%). To assess potential effect measure modification, stratified analyses of these association by levels of BMI and blood pressure showed that lower fitness levels increased risk of migraine across all groups except among underweight men or men with high diastolic blood pressure.
Conclusions Young men with a lower cardiovascular fitness had a higher long-term risk of developing pharmacological prescription-requiring migraine. This study contributes with information regarding risk factors for migraine in men, an understudied population in migraine research.
- cardiovascular fitness
- risk factor
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Contributors JN, SG, ML, NDÅ, MÅ, MW and GHK conceptualised the study. JN, SG, NDÅ, MÅ, MW and GHK contributed to data acquisition. JN, SG, JLR and TK designed the analyses, and JN and SG performed the analyses. All coauthors contributed to interpretation of as well as drafting and critically revising the manuscript for important intellectual content. JN, SG and GHK are the guarantors.
Funding This work was supported by the Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement (ALFGBG-726541, ALFGBG-715841), the Swedish Brain Research Foundation (Hjärnfonden), the Swedish Research Council (521-2014-3224) and the Stiftelsen Peter Erikssons minnesfond för hjärnforskning. JR’s research position is funded by a grant from the Else-Kröner-Fresenius Stiftung (GSO/EKFS-17, granted to TK).
Competing interests TK reports having contributed to an advisory board of CoLucid and a research project funded by Amgen, for which the Charité – Universitätsmedizin Berlin received an unrestricted compensation. He further reports having received honoraria from Lilly, Newsenselab, and Total for providing methodological advice, from Novartis and from Daiichi Sankyo for providing a lecture on neuroepidemiology and research methods, and from the BMJ for editorial services. The other authors have no conflicts of interest.
Patient consent for publication Not required.
Ethics approval The Ethics Committee of the University of Gothenburg and Confidentiality Clearance at Statistics Sweden approved this study (Dnr 462-14).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available. All data relevant to the study are included in the article or uploaded as supplementary information.
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