Temporal Dietary Patterns and Frailty in Korean Older Adults: Evening-Skewed and Morning-Evening Eating Patterns Associated with Frailty Risk

초록

Background: Meal timing has emerged as a potential determinant of healthy aging; however, evidence linking temporal dietary patterns (TDPs) with frailty remains limited. We aimed to identify distinct TDPs among older adults and examine their associations with frailty and its components. Methods: In this cross-sectional study, 4184 adults aged >= 65 years from the Korea National Health and Nutrition Examination Survey (2016-2018) were analyzed. Temporal energy-intake trajectories from 24 h recalls were clustered using dynamic time warping-based kernel k-means. Frailty was defined using a modified Fried phenotype, and diet quality was assessed employing the Healthy Eating Index. Survey-weighted logistic regression and mediation analyses were performed. Results: Five distinct patterns were identified as follows: balanced (n = 1665, 38.8%), steady (n = 735, 17.8%), midday (n = 737, 18.0%), evening (n = 627, 15.2%), and morning-evening (n = 420, 10.2%). Among these, the evening-skewed (characterized by a disproportionate concentration of energy intake in the late evening; adjusted odds ratio [OR] = 1.48, 95% confidence interval [CI] = 1.03-2.10) and morning-evening (characterized by higher energy intake in both the morning and evening; OR = 1.43, 95% CI = 1.01-2.03) patterns were associated with higher frailty risk than the balanced pattern. Mediation analysis showed that higher total energy intake had a protective role in the evening-skewed pattern; however, this benefit was offset by the adverse impact of late-night eating, resulting in increased frailty risk. In the morning-evening pattern, both a direct association with frailty and an indirect pathway mediated by lower energy intake and poorer diet quality contributed to the increased frailty risk. Conclusions: Older adults with evening-skewed or morning-evening TDPs had greater frailty risk than those with balanced eating patterns. Optimizing meal timing-by reducing late-day energy loading and ensuring adequate overall intake and dietary quality-may represent a feasible chrono-nutrition strategy for frailty prevention.

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