Association between obesity and the transitions of frailty based on multi-state Markov model: A prospective study

New evidence has revealed the dynamic transition characteristics of frailty. However, the potential differences in the effects of different types of obesity on the transition of frailty remain unclear. This prospective study aims to assess the association between obesity-related indicators and frailty transition in older adults.

This study included 2375 individuals aged ≥60, excluding underweight ones from the English Longitudinal Study of Aging (ELSA) 2008-2016. Frailty was assessed via a 60-item frailty index. Obesity was rated by 4 indicators including body mass index (BMI), waist circumference (WC), conicity index, and body roundness index (BRI). Using multi-state Markov model to evaluate how the obesity affected the probability of frailty state transitions.

During 8 years follow-up, 2517 frailty transitions were observed, with 1484 worsening and 1033 improving. Compared with normal participants, people with obesity were linked to higher risks of deterioration (non-frail to pre-frail: HR_BMI=1.32, 95 % CI=1.07-1.63, HR_WC=1.16, 95 % CI=1.00-1.35; pre-frail to frail: HR_BMI=1.90, CI=1.30-2.78; HR_WC=1.36, 95 % CI=1.03-1.81) and reduced likelihood of recovery (pre-frail to non-frail: HR_BMI=0.52, CI=0.40-0.67, HR_WC=0.66, CI=0.55-0.80). Compared with the low tertiles, the high tertiles of conicity index or BRI similarly accelerated the deterioration (non-frail to pre-frail: HR_{conicity index}=1.29, 95 % CI=1.04-1.59, HR_BRI=1.45, 95 % CI=1.20-1.76; pre-frail to frail: HR_BRI=1.58, 95 % CI=1.13-2.20) and hindered the recovery (pre-frail to non-frail: HR_{conicity index}=0.67, 95 % CI=0.53-0.84, HR_BRI=0.57, 95 % CI=0.46-0.72).

Different types of obesity all show that they accelerate the deterioration of frailty and hinder their ability to recover from frailty among older adults in UK.