Midlife BMI and A Body Shape Index in relation to mortality and coronary heart disease events in a nationwide cohort

Background Obesity is a known cardiovascular risk factor. A Body Shape Index (ABSI) is a waist circumference (WC)-based measure of abdominal obesity, independent of Body Mass Index (BMI). We examined the independent and joint associations of ABSI and BMI with long-term mortality and coronary heart disease (CHD) events among initially young to middle-aged adults. Methods Participants ( n = 2,225) were drawn from the First Israeli National Health and Nutrition Survey (1999–2001), constituting adults aged 25–64. Baseline anthropometrics, including weight, height, and WC, were measured, enabling calculation of BMI and ABSI. Follow-up lasted through 2021 for mortality and 2022 for hospitalizations. Cox regressions assessed hazard ratios (HRs) for mortality and CHD hospitalization per 1-SD increase in the allometric indices, adjusted for socio-demographics, cardiovascular risk factors, and BMI or ABSI, as appropriate. Results The baseline mean [SD] age was 43 [11] years, and 50% were women. Negligible correlation was observed between BMI and ABSI ( r = 0.02). During follow-up, 247 deaths occurred, of whom 46 of CVD, and 267 were hospitalized for incident (first-ever) CHD. The multivariable-adjusted HRs for mortality were 1.06 (95% CI: 0.92–1.21) for BMI and 1.40 (95% CI: 1.21–1.63) for ABSI. ABSI exhibited a positive association across BMI categories; HR = 1.31 (95% CI: 0.98–1.77) in 18.5–24.9, 1.47 (95% CI: 1.16–1.86) in 25–29.9, and 1.35 (95% CI: 1.05–1.74) in BMI ≥ 30. The multivariable-adjusted HRs for CHD were 1.16 (95% CI: 1.01–1.34) for BMI and 1.43 (95% CI: 1.23–1.65) for ABSI, stronger in women. Conclusion ABSI demonstrated stronger associations with mortality and CHD events than BMI and provided complementary prognostic information by identifying high-risk individuals in addition to BMI.