Abstract P255: The Longitudinal Association Between Dietary Vitamin K Intake and Cognitive Function in the General Population (Tanushimaru Cohort Study)

Background: A relationship between vitamin K intake and cognition has been shown in several studies, although most of them were cross-sectional studies. Therefore, we investigated the association vitamin K intake and cognitive change in the longitudinal cohort study. Methods: We recruited 976 participants who had a health check-up in 2009 and were followed in 2018 in a prospective Tanushimaru cohort study. We had a dietary interview using brief-type self-administered diet history questionnaire (BDHQ) and Mini-Mental State Examination (MMSE) in 2009 and 2018. Vitamin K intake was calculated based on BDHQ data. We defined people with ≦23, 24-27, 28≦ score of MMSE as dementia-level, mild cognitive impairment (MCI) and normal cognition (NC), respectively. Generalized additive model (GAM) was performed to examine non-linearity of the association between vitamin K intake in 2009 and cognitive change over time. Additionally, we estimated risks for progression from MCI to dementia-level for 9 years by multivariate logistic regression analysis. Results: The mean age was 62.6±9.0 years old and dementia-level, MCI and NC in 2009 were 1.6%, 38.7% and 59.6%, respectively. Vitamin K intake in 2009 was not associated with conversion from NC to MCI/dementia-level, but was inversely associated with progression from MCI to dementia-level. According to GAM (Fig 1), its association was linear and we defined 400 μg/day of vitamin K intake as a cut-off value. MCI participants with and low vitamin K intake (<400μg/day) in 2009 had higher risk for dementia progression compared to those with high vitamin K intake (≧400μg/day) (4.77% vs 0.67%)(Fig 2A). Additionally, regarding its concurrent relationship, MCI participants keeping high vitamin K intake from 2009 to 2018 had quite low dementia risk than those with low vitamin K intake in 2009 and 2018 (0.25% vs 5.65%) (Fig 2B). Conclusion: Higher dietary vitamin K intake was significantly associated with maintaining cognitive function for 9 years and may prevent cognitive decline to dementia-level.