Individual and cumulative association of commonly used biomarkers on frailty: a cross-sectional analysis of the Mexican Health and Aging Study

Frailty has been recognized as a common condition in older adults, however, there is scarce information on the association between frailty and commonly used biomarkers. The aim of this study was to assess the individual and cumulative association of biomarkers with frailty status. This is a cross-sectional analysis of the 2012 wave of the Mexican Health and Aging Study. A sub-sample of 60-year or older adults with anthropometric measurements was analyzed. Frailty was defined with a 31-item frailty index and those considered frail had a score ≥ 0.21. Biomarkers were further categorized as normal/abnormal and tested both one by one and grouped (according to their usual cutoff values). Adjusted logistic models were performed. A total of 1128 older adults were analyzed and their mean age was 69.45 years and 51.24% of them were women. 26.7% (n = 301) were categorized as frail. Individual biomarkers associated with frailty after adjusting for confounding were: hemoglobin [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.13–2.46, p = 0.009], glycated hemoglobin (OR 2.04, 95% CI 1.54–2.7, p < 0.001) and vitamin D (OR 1.53, 95% CI 1.13–2.07, p = 0.005). Those with ≥ 4 abnormal biomarkers had an independent association with frailty when compared to those without any abnormal biomarker (OR 2.64, 95% CI 1.3–5.25, p = 0.005). Aside from the individual associations of specific biomarkers, our findings show that an incremental association of abnormal biomarkers increases the probability of frailty, accounting for the multidimensional nature of frailty and the possible interplay between components of the system that potentiate to give rise to a negative condition such as frailty.