Background: Substantial evidence supports the inverse association between adherence to healthy dietary patterns and frailty risk. However, the role of plant-based diets, particularly their quality, is poorly known.
Objective: To examine the association of two plant-based diets with incidence of physical frailty in middle-aged and older adults.
Design: Prospective cohort.
Setting: United Kingdom.
Subjects: 24,996 individuals aged 40-70 years, followed from 2009-12 to 2019-22.
Methods: Based on at least two 24-h diet assessments, we built two diet indices: (i) the healthful Plant-based Diet Index (hPDI) and (ii) the unhealthful Plant-based Diet Index (uPDI). Incident frailty was defined as developing ≥3 out of 5 of the Fried criteria. We used Cox models to estimate relative risks (RR), and their 95% confidence interval (CI), of incident frailty adjusted for the main potential confounders.
Results: After a median follow-up of 6.72 years, 428 cases of frailty were ascertained. The RR (95% CI) of frailty was 0.62 (0.48-0.80) for the highest versus lowest tertile of the hPDI and 1.61 (1.26-2.05) for the uPDI. The consumption of healthy plant foods was associated with lower frailty risk (RR per serving 0.93 (0.90-0.96)). The hPDI was directly, and the uPDI inversely, associated with higher risk of low physical activity, slow walking speed and weak hand grip, and the uPDI with higher risk of exhaustion.
Conclusions: In British middle-age and older adults, greater adherence to the hPDI was associated with lower risk of frailty, whereas greater adherence to the uPDI was associated with higher risk.
Keywords: cohort; lifestyle; older people; prevention; unhealthy ageing; vegetarian.
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