Dietary factors in relation to the risk of cognitive impairment and physical frailty in Chinese older adults: a prospective cohort study

Purpose The study aimed to investigate the independent associations of dietary factors with cognitive impairment (CI) and physical frailty (PF) among Chinese older adults. Methods This study included 10,734 participants (mean age = 78.7 years) free of CI and PF at baseline from the Chinese Longitudinal Health Longevity Survey. Dietary intake was collected using a simplified food frequency questionnaire every 3–4 years. The Chinese version Mini-Mental State Examination was used to assess cognition function, participants with a score below 18 were defined as CI. PF was defined using the activities of daily living, instrumental activities of daily living, and functional limitation-related questions. The outcome was defined as the first onset of either CI or PF. Competing risk models were used to estimate the corresponding hazard ratios (HRs) and the 95% confidence intervals (95% CIs). Results During the study follow-up (mean = 8.1 years), a total of 1220 CI cases and 1451 PF cases were newly identified. Higher frequency of fruits intake was associated with a lower hazard of CI (HR = 0.75, 95% CI 0.58–0.97), whereas higher intake of preserved vegetables demonstrated an opposite association (HR = 1.23, 95% CI 1.07–1.42). In terms of PF, we observed a lower risk associated with higher meat and poultry intake (HR = 0.72, 95% CI 0.61–0.88). In particular, a significant protective association of fish and aquatic products intake with PF was observed among participants with ≥ 28 natural teeth (HR = 0.52, 95% CI 0.27–0.99). Conclusion Our findings suggest divergent roles of major dietary factors in the development of CI and PF among Chinese older adults.