Association of vitamin K intake with physical function, handgrip strength, and mortality among U.S. adults: NHANES...

Vitamin K (VK) plays a key role in regulating calcium homeostasis in bone and soft tissues and may be associated with physical function (PF), handgrip strength (HGS), and mortality; however, nationally-representative studies are scarce.

In this cross-sectional study, we assessed the association of VK intake with PF, HGS, and mortality in adults aged 50 and older using data from the National Health and Nutrition Examination Survey 2003-2016 (n = 4,950). VK intake was assessed using two 24-h dietary recalls and dietary supplement use questionnaires and categorized as < or ≥ the Adequate Intake (AI). Self-reported PF was categorized into 5 activities (activities of daily living, instrumental activities of daily living [IADL], lower extremity mobility [LEM], general physical activities, and leisure and social activities). HGS was measured using a grip strength dynamometer. Linear models, odds ratios, and Cox proportional hazards analyses were performed. All analytical models were adjusted for potential confounders.

VK intake meeting the AI was associated with a 0.60-fold (95% confidence interval [CI], 0.43-0.84) and 0.64-fold (95% CI, 0.47-0.89) decrease in the odds of IADL and LEM difficulty, respectively. When stratified by sex, these associations were significant only in males. However, VK intake was not associated with HGS or mortality.

VK intake meeting the AI is associated with lower odds of impaired IADL and LEM, especially in males.