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.