A paradoxical association between A Body Shape Index and cardiometabolic multimorbidity: Findings from the English longitudinal study of ageing

Background and aims: A Body Shape Index (ABSI) is a novel metric designed to more accurately reflect abdominal adiposity and visceral fat distribution - factors more strongly associated with cardiometabolic risk than body mass index (BMI) and waist circumference (WC). The association between ABSI and cardiometabolic multimorbidity (CMM) is unclear. This study aimed to assess the prospective association between ABSI and CMM risk, and to directly compare this association with those of other adiposity measures (BMI, WC, height, and weight) on CMM risk within the same population. Methods and results: We analyzed data from 3408 participants (mean age: 63 years; 44.7 % male) who were free from hypertension, coronary heart disease, diabetes, and stroke at wave 4 of the English Longitudinal Study of Ageing. ABSI was calculated as WC/(BMI^2/3height^1/2). CMM was defined as the presence of at least two chronic conditions (hypertension, cardiovascular disease, diabetes, and stroke) at wave 10. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs). Over a 15-year follow-up period, 201 participants developed CMM. Spline analysis showed a U-shaped trend between ABSI and CMM risk. Compared with the middle tertile, the multivariable adjusted ORs (95 % CIs) for CMM were 1.57 (1.10–2.25) for the lowest tertile and .97 (.64–1.48) for the highest tertile. Increased levels of BMI, WC, height, and weight were each associated with an elevated CMM risk. Conclusion: There was a U-shaped relationship between ABSI and CMM risk, with low ABSI being associated with an increased CMM risk.