Risk factors associated with cognitive frailty development through different transition pathways among community-dwelling older adult Japanese individuals: insights from the NILS-LSA project

The risk factors on the transition from robustness to cognitive frailty (CF), characterized by concurrent cognitive impairment and physical frailty (PF), may vary through different transition routes. Data from the National Institute for Longevity Sciences-Longitudinal Study of Aging (2000−2012) were analyzed, including data for 1,061 older individuals (baseline age: 60–83 years; 51.5% men) who had a Mini-Mental State Examination (MMSE) score ≥ 24, and were dementia- and CF-free at baseline. Mild cognitive impairment (MCI) was defined as a MMSE score 24–27, PF as ≥ 1 Fried criteria, and CF as both conditions. Dietary diversity (assessed using the Quantitative Index for Dietary Diversity score; 0–1) and energy intake were categorized into sex-specific tertiles (T1–T3). Multistate modeling estimated hazard ratios of risk factors for transitions among robustness (no MCI and PF), MCI, PF, and CF states. At baseline, robustness, MCI, and PF proportions were 36.9%, 14.4%, and 48.7%, respectively. In robust individuals, aging increased (HR = 1.22), and high dietary diversity (HR = 0.62 for T3) and higher energy intake (HR = 0.36 for T2, 0.37 for T3) mitigated MCI risk. Conversely, obesity (HR = 1.37) and smoking (HR = 1.66) elevated, and stroke history (HR = 0.43) and high dietary diversity (HR = 0.63 for T3) lowered PF risk. Among those with MCI, female sex (HR = 1.69) and higher education (HR = 1.75 for 10−12 years, 2.19 for ≥ 13 years) facilitated recovery, while moderate energy intake impeded it (HR = 0.40 for T2). Aging (HR = 1.32), female sex (HR = 2.63), and smoking (HR = 2.91) increased CF risk, whereas moderate energy intake mitigated it (HR = 0.50 for T2). In PF participants, moderate dietary diversity (HR = 1.49 for T2), high energy intake (HR = 1.39 for T3), and alcohol consumption (HR = 1.32) promoted recovery, while depressive symptoms (HR = 0.25) and living alone (HR = 0.58) hindered it. Aging (HR = 1.28) increased CF risk, whereas higher education decreased it (HR = 0.55 for 10−12 years, 0.54 for ≥ 13 years). Tailoring intervention strategies according to specific health statuses of older adults may prevent and delay CF onset and facilitate recovery from MCI and PF.