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

Abstract

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. We present a cross-sectional analysis of the Costa Rican Longevity and Healthy Aging Study. This report is from a representative sample of Costa Rican older adults; one of the countries that integrate the Central America region. 2,827, 60-year or older community-dwelling individuals. 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. 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). 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.