The older, the less potential benefit for type 2 diabetes from weight control

BACKGROUND: Although moderate weight loss improves outcomes of type 2 diabetes mellitus (T2DM) in young and middle-aged adults, there is a lack of high-quality evidence to support the strong relationship between obesity and T2DM in older people. This study aims to investigate whether the association of obesity with T2DM changes with aging. METHODS: In this cross-sectional study, we recruited 63,180 Chinses and US subjects from 3 datasets. Subjects were divided into young & middle-aged (≤59 years), young-old (60–75 years), and old-old (≥75 years). Logistic regression was used to determine the odds ratio (OR) and 95% confidence intervals (95% CI) for the association between obesity and T2DM, stratified by common confounders. A sliding-window based algorithm and restricted cubic splines were used to smoothly estimate the changes with aging. RESULTS: The OR (95% CI) for the associations between general obesity and T2DM were decreased from the young & middle-aged group (OR, 5.91; 95% CI, 5.33–6.56) to the young-old group (OR, 3.98; 95% CI, 3.56–4.45) and then to the old-old group (OR, 3.06; 95% CI, 2.57–3.66). The trend for this reduced association with aging persisted after stratification by obesity type, region, gender, recruiting time, hypertension, and hyperlipidemia in both Chinese and Americans. We also identified a weakened gender disparity for this association between the young & middle-aged subjects (P for disparity < 0.001) and the old-old group (P for disparity = ~ 0.36). CONCLUSIONS: The obesity-T2DM association is clearly reduced with aging, which indicates that the elderly may gain fewer potential benefits in weight lose than the younger patients. Considering this attenuated association, as well as the increased incidence of geriatric syndrome in the elderly, clinicians should comprehensively balance the benefits and side effects of weight loss in geriatric T2DM interventions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-022-02979-8.