Association of dietary patterns with mortality and life expectancy by frailty status: Evidence from the UK Biobank

Whether healthy dietary patterns can reduce mortality and extend life expectancy across different frailty status remains unclear. We aimed to investigate the associations of four dietary patterns with mortality and life expectancy both in the overall population and by frail status.

We included 208,379 participants from the UK Biobank. Dietary intake was collected by the 24-h dietary recall assessments. Dietary patterns were assessed using previously established indices: alternative Mediterranean Diet (aMED), Dietary Approaches to Stop Hypertension (DASH), Plant-based Diet Index (PDI), and Planetary Health Diet Index (PHDI). Frailty status was defined by Fried's phenotype and classified into robust, prefrailty, and frailty. Cox proportional hazards models and flexible parametric survival models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between dietary patterns and mortality and life expectancy.

After a median follow-up of 13.42 years, 12,571 deaths occurred. Participants with the highest adherence to a healthy pattern exhibited reduced all-cause mortality (HR ranged from 0.76 to 0.88) and longer life expectancy (years of life gained ranged from 1.84 to 3.16). The protective effects were consistent across different frailty status, and a more substantial prolongation of life was observed in frail individuals. Taking aMED as an example, the HRs and 95% CIs of mortality for the highest tertile of adherence versus the lowest were 0.80 (0.75-0.86) in robust individuals, 0.76 (0.70-0.82) in pre-frail individuals, and 0.65 (0.50-0.86) in frail individuals, and life expectancy gains were 2.45 (2.03-2.87), 3.27 (2.72-3.82), and 5.57 (3.19-7.95) years, respectively. Women had a higher overall life expectancy than men, whereas men showed greater life expectancy gains from dietary adherence.

Higher adherence to aMED, DASH, PDI, and PHDI could reduce all-cause mortality and extend life expectancy regardless of frailty status.