Higher Dietary Vitamin K Intake is Associated with Better Physical Function and Lower Long-Term Injurious Falls Risk in Community-Dwelling Older Women

Abstract

BackgroundIn recent years, a potential beneficial role of Vitamin K in neuromuscular function has been recognised. However, the optimal dietary intake of Vitamin K to support muscle function in the context of falls prevention remains unknown.ObjectiveTo examine the relationship of dietary Vitamin K1 and K2 with muscle function and long-term injurious fall-related hospitalisations in older women.DesignCohort study.Participants1347 community-dwelling older Australian women ≥70 years.MeasurementsA new Australian Vitamin K nutrient database, supplemented with published data, was used to calculate Vitamin K1 and K2 intake from a validated food frequency questionnaire at baseline (1998). Muscle function (grip strength and timed-up-and-go; TUG) as well plasma Vitamin D status (25OHD) were also assessed at baseline. Fall-related hospitalisations over 14.5 years were obtained from linked health records. Multivariable-adjusted logistic regression and Cox-proportional hazard models were used to analyse the data.ResultsOver 14.5 years of follow-up (14,774 person-years), 535 (39.7%) women experienced a fall-related hospitalisation. Compared to women with the lowest Vitamin K1 intake (Quartile 1, median 49 µg/d), those with the highest intake (Quartile 4, median 120 µg/d) had 29% lower odds (OR 0.71 95%CI 0.52–0.97) for slow TUG performance (>10.2 s), and 26% lower relative hazards of a fall-related hospitalisation (HR 0.74 95%CI 0.59–0.93) after multivariable adjustment. These associations were non-linear and plateaued at moderate intakes of ∼70–100 µg/d. There was no relation to grip strength. Vitamin K2 intakes were not associated with muscle function or falls.ConclusionA higher habitual Vitamin K1 intake was associated with better physical function and lower long-term injurious falls risk in community-dwelling older women. In the context of musculoskeletal health, Vitamin K1 found abundantly in green leafy vegetables should be promoted.