Obesity paradox, weight-free anthropometric measures, and major adverse cardiovascular events in the elderly: insight from the northern shanghai study

Objective: Many studies have investigated the obesity paradox in the elderly. However, besides body mass index (BMI), many other anthropometric measures, such as the waist-to-hip ratio (WHR), provide a better indication of body fat distribution and may be more useful in a geriatric population. Design and method: 3285 participants aged over 65 years old from the Northern Shanghai Study were included in this analysis. Eight anthropometric measures, including weight-related measures (BMI, weight-adjusted-waist index, body shape index and body surface area) and weight-free measures (WHR, waist-to-height ratio, body roundness index, relative fat mass) were measured and calculated with standard methods. Major adverse cardiovascular events (MACEs) included the non-fatal myocardial infarction, non-fatal stroke or cardiovascular death. Results: Participants had an average age of 71.4 years and 1428 (43.47%) were men. The median follow-up was 5.4 years (IQR, 4.4-7.3 years) and 218 events occurred. Participants with obesity were associated with a higher risk of MACEs compared with the normal (adjusted Hazard ratio = 1.54, 95% confidence interval (CI): 1.07-2.22, P=0.020). Restricted cubic splines also highlighted the robust correlation between high BMI and high MACEs risk (Pfor overall=0.025, Pfor nonlinear=0.339). Similarly, the aHR for the incidence of MACEs in WHR quartile 4 versus quartile 1 was 1.96 (95% CI: 1.26-3.05, P=0.003). When WHR was examined as a continuous variable, the result remained unaltered (Pfor overall=0.020, Pfor nonlinear=0.353). In adjusted model, all four weight-free measures were significantly associated with increased risk of MACEs (all P<0.05), while only two weight-related measures were related to the risk of MACEs. Conclusions: In the elderly, BMI and alternative anthropometric measures showed no evidence of an obesity paradox. Weight-free measures were more relevant to a risk of MACEs.