Age-specific associations between intrinsic capacity impairments and self-rated health in community-dwelling adults: Insights from Taiwan longitudinal study on aging

BACKGROUND: The World Health Organization's Integrated Care for Older People framework emphasizes intrinsic capacity (IC) assessment, yet the relationship between specific intrinsic capacity impairments and self-rated health (SRH) across different age groups remains inadequately characterized. OBJECTIVES: To analyze age-specific associations between six IC domains and self-rated health using Taiwan Longitudinal Study on Aging data, adjusting for demographic, socioeconomic, and health factors. METHODS: We extracted 3,330 participants with good or poor self-rated health, stratified into three age groups: 55-64 years (n = 1,278), 65-74 years (n = 1,011), and 75+ years (n = 1,041). Five sequential logistic regression models assessed associations between IC impairments (locomotor capacity, vitality, vision, hearing, cognition, psychological capacity) and self-rated health, adjusting for sex, education, marital status, employment, economic satisfaction, chronic conditions, smoking, drinking, physical exercise, and sleep quality. RESULTS: IC impairment prevalence increased with age: 17.2% (55-64), 38.2% (65-74), and 61.5% (75+). After adjustment, age-specific patterns of IC impairments associated with poor self-rated health emerged. In middle-aged adults (55-64), locomotor capacity showed the strongest association with poor self-rated health (OR = 14.61, 95% CI: 3.50-61.01), though the wide confidence interval reflects the low prevalence of impairment. Psychological capacity (OR = 5.96, 95% CI: 3.32-10.69) could thus be the most dominant IC impairment that is linked to poor self-rated health in this age group. For young-old adults (65-74), locomotor capacity had the greatest impact (OR = 4.19, 95% CI: 2.02-8.67), followed by psychological capacity (OR = 3.68, 95% CI: 2.33-5.82) and vitality (OR = 2.14, 95% CI: 1.11-4.16). In the oldest adults (75+), vitality became particularly important (OR = 4.17, 95% CI: 2.22-7.84), alongside with psychological capacity (OR = 3.15, 95% CI: 2.18-4.56) and locomotor capacity (OR = 2.20, 95% CI: 1.52-3.17). CONCLUSIONS: Age-specific patterns suggest targeted interventions: mental health support for middle-aged adults, mobility preservation for young-old adults, and vitality enhancement for the oldest adults. These findings provide guidance for age-tailored ICOPE strategies.