Validation of Two Intrinsic Capacity Scales and Its Relationship with Frailty and Other Outcomes in Mexican Community-Dwelling Older Adults.

OBJECTIVES: The aim of this study was to compare a short and a long version of an intrinsic capacity index and test their cross-sectional association with relevant health outcomes in older adults. DESIGN: Cross-sectional analysis of the baseline data of the FraDySMex study. PARTICIPANTS: 543 community-dwelling adults aged 50 years and older living in 2 municipalities in Mexico City, from which 435 had complete data on the variables of interest. METHODS: The intrinsic capacity indices were obtained using principal components analysis. The performance of the indices was tested respective to frailty, IADL and ADL. RESULTS: The short and long versions of the IC index performed well for assessing functional status. Using biometrical variables like the phase angle, grip strength and gait speed measured by the GAIT rite improved the index performance vis a vis IADL disability (Lawton), but not to the other evaluated outcomes. CONCLUSIONS: Both the long and short versions of the intrinsic capacity indices tested were able to classify older adults according to their functional status and were associated with relevant health outcomes.

In the quest of a Standard Index of Intrinsic Capacity. A Critical Literature Review.

OBJECTIVES: Intrinsic capacity is a composite of five domains that summarizes the physical and mental capacities of an individual. Intrinsic capacity is increasing in relevance for adapting health systems to population ageing. Therefore, our objective was to analyse how intrinsic capacity has been assessed in older adults and if these measurements have been validated, as an initial step towards the construction of a standard intrinsic capacity index. DESIGN: Narrative review with electronic searches performed in PubMed and Cochrane databases, including the studies which used the term "intrinsic capacity" in the context of human ageing and health. The full text was then accessed to select studies with at least one operationalised domain of intrinsic capacity. We also looked for information on the validity and reliability of the reported measures of intrinsic capacity. RESULTS: We included ten articles reporting a quantitative measurement of intrinsic capacity. There were two intrinsic capacity scores which combined retrospective data on the intrinsic capacity domains sub-scores, with low concordance among tests chosen to measure each domain. Two studies reported on reliability and validity of the IC scores. The main gaps in the construction and validation process were a) analysis undertaken with each domain separately rather than for the construct of intrinsic capacity, b) lack of a clear conceptual and operational definition of the vitality domain, c) summary score that depends upon the distribution of the study sample. CONCLUSION: Further validation of the intrinsic capacity concept is needed, together with more robust approaches to measure it. A standard index of IC has not been validated for translation into clinical or research purposes.

Allostatic Load as a Biological Substrate to Intrinsic Capacity: A Secondary Analysis of CRELES.

OBJECTIVES: Intrinsic capacity (IC) is one of the latest views of positive aging. In its current status lacks a biological substrate amenable to be intervened. The aim of this study was to determine the association of allostatic load (AL) with IC. DESIGN: We present a cross-sectional analysis of the Costa Rican Longevity and Healthy Aging Study. SETTING: This report is from a representative sample of Costa Rican older adults; one of the countries that integrate the Central America region. PARTICIPANTS: 2,827, 60-year or older community-dwelling individuals. METHODS: An IC index was gathered and validated, including different domains: cognitive, psychological, sensory, vitality and locomotion. AL was integrated with: blood pressure, abdominal obesity, body mass index, HDL-cholesterol, glycosylated hemoglobin, DHEAS, cortisol, epinephrine and norepinephrine. AL was grouped in three categories according to the number of abnormal biomarkers (0-1, 2-3 and ≥4). Chronic diseases, socioeconomic level, sex and age were the adjusting variables. Ordinal logistic regression models were estimated in order to test the strength of the association. RESULTS: From a total sample of 1,888 individuals, 51% (n=962) were women, 36.4% were in the 60-69 age category. The mean score of the IC index was of 6.6 (±2.2). Odds ratio (OR) of the adjusted models were significant for the group of those with 2-3 abnormal biomarkers of AL (OR 0.67, p=0.007) and also for those with ≥4 (OR 0.56, p=0.002), when compared to the reference group of AL (0-1 abnormal biomarkers). CONCLUSIONS AND IMPLICATIONS: AL showed an incremental association with IC, even when adjusted for factors such as socioeconomic status and chronic diseases. Targeting therapeutically AL could potentially improve IC in older adults and therefore decreasing the progression to disability or to overt dependency.