Importance: Intrinsic capacity (IC), defined by the World Health Organization's Integrated Care for Older People (ICOPE) framework, is crucial for promoting healthy aging. Understanding the associations between IC impairments and age-related biomarkers can provide insights into the underlying pathophysiological mechanisms and potential interventions.
Objective: To investigate the associations between IC impairments (ICOPE step 1 and step 2, respectively) and aging-related biomarkers, including inflammatory and cardiometabolic markers, in community-dwelling middle-aged and older adults.
Design, setting, and participants: Cross-sectional analysis of data from 755 participants (aged 50-64 years, n=212; 65-74 years, n=357; ≥75 years, n=186) enrolled in the Gan-Dau Healthy Longevity Plan, a community-based survey in Taipei City, Taiwan, from 2022.
Exposures: IC impairments assessed by ICOPE Step 1 (screening) and Step 2 (in-depth assessment) across six domains: locomotion, vitality, vision, hearing, cognition, and psychological well-being.
Main outcomes and measures: Levels of inflammatory biomarkers (albumin, white blood cell count, neutrophils, lymphocytes, monocytes, neutrophil-to-lymphocyte ratio [NLR], lymphocyte-to-monocyte ratio [LMR], platelet-to-lymphocyte ratio [PLR]) and cardiometabolic biomarkers (low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], total cholesterol, fasting glucose, triglycerides, triglyceride-glucose [TyG] index).
Results: Of the 755 participants, the mean age was 68.5 years, and 68.2% were women. The proportion of participants with any IC impairment increased with age: 63.2% for those aged 50-64, 65.8% for those aged 65-74, and 74.7% for those aged ≥75 years based on ICOPE Step 1. For ICOPE Step 2, the proportions were 59.9%, 56.9%, and 64.0%, respectively. Impairments in locomotion and cognition were significantly higher in the oldest age group (≥75 years). Adjusted for covariates, IC impairment (ICOPE Step 2) was associated with higher levels of neutrophil count (β = 3.17, p = 0.015) and NLR (β = 0.34, p = 0.021) in those aged 50-64 years, and higher levels of monocyte count in those aged 65-74 years (β = 0.65, p = 0.001) and ≥75 years (β = 0.68, p = 0.037).
Conclusions and relevance: In conclusion, IC impairments were associated with alterations in specific inflammatory biomarkers, suggesting potential interactions between IC, age, and inflammatory processes. Longitudinal studies are warranted to establish causal relationships and elucidate the underlying mechanisms linking IC impairments, immune dysregulation, and the aging process.
Keywords: Integrated Care for Older People (ICOPE); Intrinsic capacity; cardiometabolic risk; healthy longevity; immune resilience.