Social vulnerability and health determinants of Intrinsic Capacity in Mexican older adults: Evidence from the Mexican Health and Aging Study round 2021.

BACKGROUND: Population aging has increased interest in Intrinsic Capacity (IC), defined as the composite of physical and mental abilities that support healthy aging. Because declines in IC precede disability, IC is a useful framework for characterizing individuals with greater vulnerability in later life. METHODS: We conducted a cross-sectional analysis of the 2021 Mexican Health and Aging Study, a nationally representative survey of adults aged 50 years and older. IC was assessed across five domains using domain-specific impairment, number of impaired domains, and a continuous latent IC score derived from factor analysis. Ordinal logistic regression models were used to examine associations with sociodemographic characteristics, health conditions, and a Social Vulnerability Index (SVI) constructed using a cumulative deficit approach. FINDINGS: The sample included 13,403 adults (mean age 65.9 years [SD 9.8]; 57.3% women). IC impairment was highly prevalent: 67.1% had impairment in two or more domains, whereas only 12.5% had no impaired domains. Lower IC was associated with increasing age (≥80 years: OR 3.31; 95% CI 1.10-10.02) and poorer health, including multimorbidity (OR 2.29; 95% CI 1.44-3.64) and poor self-rated health (OR 1.69; 95% CI 1.24-2.28). Lower IC was further associated with social disadvantage, including lower educational attainment (OR 2.33; 95% CI 1.69-3.22) and food insecurity (OR 1.51; 95% CI 1.06-2.16), with higher social vulnerability associated with lower IC (β -0.46; 95% CI -0.51 to -0.41). INTERPRETATION: IC impairment is highly prevalent among Mexican adults aged 50 years and older and is strongly associated with social vulnerability and modifiable health factors, supporting IC as an integrative framework to identify vulnerable individuals and inform intervention strategies.