BMI, weight change, and incidence of disability among Korean adults: A nationwide retrospective cohort study

Background: Little is known about the risk of acquired disability diagnosed by a physician in relation to baseline BMI and weight change, particularly in the Asian population. Objective: This study assessed the association of baseline BMI and weight change with incidence of disability. Methods: This study included 331,900 individuals aged ≥40 years who participated in two health-screening programs since 2002 or 2003 and who were followed up until 2013. This study measured the baseline BMI and weight change for two years and estimated the adjusted hazard ratio (aHR) of the risk of acquired disability diagnosed by a physician using a Cox proportional hazards model. Results: This study identified 1758 incident disability cases during an average follow-up period of 10.7 ± 1.3 years from baseline (9.1 ± 1.4 years from the follow-up health screening). Baseline underweight (BMI<18.5 kg/m²) was associated with an increased risk of acquired disability compared with those with normal BMI (aHR, 1.44; 95% confidence interval [CI], 1.14–1.83). The risk of acquired disability was higher in individuals with weight loss of 5–10% (aHR, 1.21; 95% CI, 1.04–1.40), weight loss of ≥10% (aHR, 1.61; 95% CI, 1.27–2.04), weight gain of 5–10% (aHR, 1.30; 95% CI, 1.12–1.52), or weight gain of ≥10% (aHR, 1.35; 95% CI, 1.09–1.75) compared to those with weight change of <5%. Conclusion: This study demonstrated that baseline underweight and weight changes (both loss and gain) are associated with an increased risk of acquired disability.