The Association Between Weight-Adjusted Waist Index and Successful Aging Among China Older Adults

Background This study examined the association between weight-adjusted waist index (WWI) and successful aging and its specific components among older Chinese adults. Methods A total of 4,220 participants aged ≥ 60 years (68.35 ± 6.50) were included. WWI, an indicator of obesity calculated from waist circumference (WC) and body weight, was used as the main exposure variable. Successful aging comprises five dimensions: absence of major diseases, freedom from disability, high cognitive function, good psychological status, and active social engagement. To examine the association between WWI and successful aging, logistic regression models were conducted with WWI analyzed both as a continuous variable and in quartiles. Comparative analyses using body mass index (BMI) and WC were performed under the same modeling strategy. Subgroup analyses were conducted to assess the consistency of associations across different populations. All models were adjusted for eight covariates. Results The rate of successful aging was 35.2%. In adjusted models, higher WWI was significantly associated with lower odds of successful aging. Compared with Q1, the OR for Q4 was 0.73 (95% CI: 0.60–0.89; p for trend = 0.002). Higher WWI was also inversely associated with two key dimensions of successful aging: absence of major diseases and freedom from disability. Each one-unit increase in WWI corresponded to an 11% reduction in the likelihood of successful aging (OR = 0.89, 95% CI: 0.82–0.96; p < 0.001). This association was stronger than that for BMI and WC, and remained consistent across subgroups. Conclusion Our study highlights a strong association between WWI and successful aging. Compared to BMI and WC, WWI is a more reliable predictor. Maintaining a lower WWI may substantially enhance older adults' capacity to manage aging-related challenges. This is particularly critical for older adults and women.