Body mass index and activities of daily living impairment: systematic review and meta-analysis

Both underweight and obesity have been linked to increased risk of disability, yet evidence on the relationship between body mass index (BMI) and activities of daily living (ADL) impairment remains inconsistent. To examine these associations in adults, we conducted this systematic review and meta-analysis following the standard methods and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Six databases were searched from inception to August 12, 2024. The protocol is registered in the PROSPERO (CRD42022357046). Abstracts and full-text articles describing associations between BMI and ADL impairment were screened using Rayyan software. Study quality was assessed using the RoBANS tool. A random-effects model meta-analysis was performed using metaanalysisonline, a web-based meta-analytic platform, with BMI categories of <18.5 (underweight), 25-29.9 (overweight), and ≥30 (obese) as exposures, and 18.5-24.9 (normal) as the reference. Of the initial 25,212 articles identified, 132 studies met the inclusion criteria. The meta-analysis showed positive association in both longitudinal studies [odds ratio (OR) 1.77, 95% confidence interval (CI): 1.54-2.03] and cross-sectional studies (OR: 1.56, 95% CI: 1.38-1.76). Overweight individuals exhibited a moderate increase in ADL risk in longitudinal studies (OR: 1.19, 95% CI: 1.09-1.30), but not in cross-sectional studies (OR: 1.06, 95% CI: 0.95-1.18). Both longitudinal and cross-sectional studies revealed a positive association between underweight participants and ADL impairment (OR: 1.20, 95% CI: 1.02-1.42; OR: 1.46, 95% CI: 1.24-1.72, respectively). Individuals with higher BMI, as well as those who are underweight, are at increased risk of ADL limitations.