Effect Size Estimates of Risk Factors for the Impaired Intrinsic Capacity Among Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis

OBJECTIVES: To provide updated evidence on the risk factors and accurately quantify the effect size of the risk factors associated with intrinsic capacity (IC), encompassing locomotion, vitality, cognition, psychological, and sensory function. DESIGN: Systematic review and meta-analysis. SETTING AND PARTICIPANTS: Older people living in community. METHODS: In accordance with the PRISMA guidelines, we conducted a systematic review of the literature by 2 reviewers across 5 databases from inception to March 2025. The meta-analysis was conducted to calculate an effect size for each risk factor, and odds ratios and 95% confidence intervals were used as summary statistics. This study was registered in the PROSPERO (CRD420251036521). RESULTS: A total of 3602 studies were screened in our review, of which 54 were included in qualitative synthesis and 20 were included in quantitative synthesis. A total of 91 factors were identified, categorized into 8 in demographic, 12 in socioeconomic, 27 in behavioral, 30 in disease-related, and 14 in health-related biomarkers categories. The risk factors that were significantly correlated with impaired IC were observed for "older age," "females," "lower level of education," "being unmarried," "financial strain," and "comorbidity." Focus on 5 domains of IC, only "females" and "living alone" were significantly associated with the psychological domain. CONCLUSIONS AND IMPLICATIONS: This systematic review and meta-analysis identified and quantified the risk factors associated with impaired IC, which will facilitate the creation of targeted interventions aimed at preventing impaired IC and lessening its adverse effects on health. Quantitative analysis is still needed with additional studies in the future. Targeted prevention approaches should mitigate IC impairment by focusing on the modifiable risk factors.