Dietary vitamin E intake and all-cause mortality in patients with osteoarthritis: a prospective cohort study using...

The potential influence of dietary vitamin E in osteoarthritis (OA) progression has been explored; however, its association with mortality risk in patients with OA remains unclear. This study aimed to investigate the relationship between dietary vitamin E intake and all-cause mortality among US adults with OA.

This cross-sectional analysis included 2,974 adults with OA from the National Health and Nutrition Examination Survey cycles spanning 2003-2018. Mortality data were obtained by linking to the National Death Index, with follow-up until December 31, 2019. Cox proportional hazards models were used to evaluate the association between dietary vitamin E intake and all-cause mortality in patients with OA. Restricted cubic spline analyses investigated potential nonlinear dose-response relationships. Stratified analyses further explored mortality risk variations across subgroups to identify high-risk populations.

After comprehensive multivariable adjustment, a higher dietary vitamin E intake was significantly inversely associated with all-cause mortality in patients with OA (P for trend < 0.001). Compared with the lowest quartile (Q1) of intake, the adjusted hazard ratios (HRs) for mortality in Q2, Q3, and Q4 were 0.86 [95% confidence interval (CI) 0.74-1.00], 0.76 (95% CI 0.64-0.90), and 0.61 (95% CI 0.50-0.74), respectively. Restricted cubic spline analysis revealed a nonlinear relationship (P for nonlinearity = 0.025), with a threshold effect observed at 8.554 mg/day vitamin E consumption. Below 8.55 mg/day, each 1-mg increment in vitamin E intake reduced the mortality risk by 7.6% (HR: 0.92, 95% CI 0.89-0.96; P < 0.001) without significant correlation above this threshold (HR: 0.98, 95% CI 0.95-1.01; P = 0.23).

This national cohort study revealed a nonlinear inverse association between dietary vitamin E intake and mortality in patients with OA, with a threshold of 8.55 mg/day. Sub-threshold intake demonstrated a significant reduction in mortality, potentially informing OA nutritional management. Therefore, prospective studies are required to establish causality.