Associations between dietary vitamin K1 and K2 intake and incident dementia: findings from the Danish Diet, Cancer, and Health cohort

Vollständiger Abstract

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Abstract Purpose Vitamin K is hypothesised to support vascular integrity and neuronal function through vitamin K-dependent proteins, yet epidemiological evidence for its role in dementia, particularly distinguishing vitamin K1 and K2, is limited. This aetiological study examined associations between dietary vitamin K1 and K2 with incident dementia in a large Danish cohort. Methods We included 54,968 dementia-free participants (47.5% male, aged 50–65 years) from the Danish Diet, Cancer, and Health cohort (1993–1997) with dietary vitamin K1 (µg/day), and K2 (µg phylloquinone equivalent/day) intakes estimated from a 192-item food frequency questionnaire. Incident and early-onset dementia were identified through national registries. Cox proportional hazard models with restricted cubic splines estimated hazard ratios (HR) across quintiles of intake, adjusting for demographic, lifestyle, dietary factors, and prevalent comorbidities. Results Over a maximum of 28 years of follow-up (median [IQR]: 25.5 [16.1–26.5] years), 4802 (8.7%) participants developed dementia. Vitamin K1 intake showed an inverse association with dementia, with a 14% lower rate in quintile (Q) 5 versus Q1 (HR Q5vsQ1 [95%CI]: 0.86 [0.78–0.93]). The association was stronger for early-onset dementia (< 65 years). In contrast, vitamin K2 intake was associated with higher dementia risk, whereby those with the highest intakes had 14% higher rate (HR Q5vsQ1 [95%CI]: 1.14 [1.04–1.24]). Conclusion Higher vitamin K1 intake was associated with lower dementia risk, while higher K2 intake was associated with higher risk. These associations may be confounded by dietary patterns and food sources associated with each vitamin form and warrant further investigations. Nevertheless, greater intake of vitamin K1-rich vegetables (e.g. spinach, cabbages, broccoli, etc.) as part of broader dietary patterns may be relevant to cognitive health.