Longitudinal association between Body mass index (BMI), BMI trajectories and the risk of frailty among older adults: A systematic review and meta-analysis of prospective cohort studies

Abstract

ObjectiveWe aimed to determine whether BMI categories and BMI trajectories were longitudinally associated with frailty in older adults via systematic review and meta-analysis of prospective cohort studies. Method3 databases (PubMed/MEDLINE, EMBASE and Web of Science) were systematically searched from inception to 8 September 2023. Two independent reviewers extracted data and appraised study quality. The quality of the studies was assessed using the Newcastle-Ottawa Scale. Data were pooled using random-effects models. Results7 prospective cohort studies with 23043 participants were included in final BMI categories analyses, and 3 studies included BMI trajectory(23725 individuals). Compared with normal weight, we found a positive association between obesity (odds ratios(OR) = 1.74, 95 % confidence interval (CI): 1.21-2.51, P = 0.003), underweight (OR = 1.70, 95 % CI: 1.13-2.57, P = 0.011) and frailty in older adults. In middle age subgroup, compared with normal weight, OR of 2.21 (95 % CI: 1.44-3.38;I2 = 0 %) for overweight and OR of 5.20 (95 % CI: 2.56-10.55; I2 = 0 %) for obesity were significantly associated with frailty. In old age subgroup, compared with normal weight, only OR of 1.41 (95 % CI: 1.13-1.77; I2 = 65 %) for obesity was significantly associated with frailty. The results of BMI trajectories found that decreasing BMI (OR = 3.25, 95 % CI: 2.20-4.79, P < 0.0001) and consistently high BMI (OR = 3.66, 95 % CI: 2.03-6.61, P < 0.0001) increase the risk of frailty compared to consistently normal or overweight. ConclusionOverweight and obesity in middle age were associated with significantly higher frailty in older adults, while obesity and underweight in old age were associated with relatively higher frailty in older adults. Early weight control may be beneficial for old age.