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

PurposeVitamin 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.MethodsWe 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.ResultsOver 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 (