Association between central obesity and ADL impairment among the middle-aged and elderly population in China based on CHARLS.

To explore the associations of central obesity indicators including waist circumference (WC), waist-to-height ratio (WHtR), and weight-adjusted waist index (WWI) with the impairment of basic activities of daily living (BADL) and instrumental activities of daily living (IADL) among middle-aged and elderly population in China. This prospective study used baseline data from 2011 and follow-up data, involving 6440 and 9646 participants, respectively. Binary logistic regression analysis was used to assess the relationships. Restricted cubic spline (RCS) curve was also used to analyze the correlation trends. Stratified analyses were performed to identify potential differences. Receiver operating characteristic curves were plotted to evaluate the predictive value of each indicator. WC (OR = 1.01, 95% CI:1.01-1.02), WHtR (OR = 1.21, 95% CI = 1.09-1.33), and WWI (OR = 1.10, 95% CI:1.02-1.19) were significantly associated with BADL impairment. Only WWI (OR = 1.16, 95%CI:1.09-1.23) was associated with IADL impairment. WC, WHtR and WWI were linearly associated with BADL impairment while WWI was linearly associated with IADL impairment. The risk association between WWI and BADL was stronger in drinking individuals and males. In the participants with a BMI less than 24 kg/m² and who had received a high school education or above, the increase in WWI was accompanied by a more significant risk of IADL impairment. The predictive ability of WWI is higher than that of WC and WHtR, with AUC values of 0.597 and 0.615. WWI, as a comprehensive indicator of central obesity, may be useful in comprehensively identifying the risk of early daily living activity impairment among middle-aged and elderly population.