Background: Dietary vitamin K intake is thought to decrease the risk of cardiovascular disease (CVD) by reducing vascular calcification, although vitamin K is also involved in coagulation. Studies investigating the association between phylloquinone intake and risk of stroke are scarce, and the relation with menaquinones has not been investigated to date.
Methods and results: We investigated the association between intake of phylloquinone and menaquinones and stroke in a prospective cohort of 35,476 healthy subjects. Information on occurrence of stroke was obtained by linkage to national registries, and stroke was further specified into ischemic and hemorrhagic stroke. Vitamin K intake was estimated using a validated food-frequency questionnaire. Multivariate Cox proportional hazards models adjusted for cardiovascular risk factors, lifestyle, and other dietary factors were used to estimate the associations. During a follow-up of 12.1 ± 2.1 years, 580 incident cases of stroke were identified, 163 of which were hemorrhagic and 324 were ischemic. Phylloquinone intake was not associated with risk of stroke with a hazard ratio (HR) of 1.09 (95% CI: 0.85 to 1.40, P(trend) 0.41) for the highest versus lowest quartile. For intake of menaquinones similar results were found, with an HR(Q4 versus Q1) of 0.99 (95% CI: 0.75 to 1.29, P(trend) 0.82). When specifying hemorrhagic and ischemic stroke or menaquinone subtypes, no significant associations were detected.
Conclusion: In our study, neither dietary phylloquinone nor dietary menaquinones intake were associated with stroke risk.
Keywords: diet; menaquinone; phylloquinone; stroke; vitamin K.