The weight-adjusted-waist index predicts all-cause and cardiovascular mortality in general US adults

BACKGROUND: The authors examined the relationship between Weight-adjusted Waist Index (WWI) and all-cause and cardiovascular mortality among adults in the US. METHODS: This prospective cohort study included 26,882 individuals who participated in the National Health and Nutrition Examination Survey (NHANES) from 2005 through 2014. WWI was calculated as waist circumference divided by the square root of weight. The main outcomes of this study were all-cause mortality and cardiovascular mortality. Mortality status and cause of death were determined by NHANES-linked National Death Index records through December 31, 2015. Cox proportional hazard models and Kaplan-Meier analysis were used to estimate Hazard Ratios (HR) and 95% CIs for mortality for all causes and cardiovascular diseases. RESULTS: A total of 26,882 participants with a mean WWI of 10.89 ± 0.01, of whom 49.23% were male. The average follow-up time was 68.95 ± 1.07 months, and 1870 participants were determined as deceased (4.99%), including 349 cardiovascular death (0.88%). The Kaplan-Meier analysis demonstrated a significant difference in all-cause and cardiovascular mortality between patients with WWI <11.33 and ≥11.33 (both log-rank test p < 0.0001). The fully adjusted Cox proportional hazard model indicated that a higher WWI level (≥ 11.33) was associated with an increased 95% risk for cardiovascular mortality (HR = 1.95, 95% CI 1.30‒2.93) and 68% risk for all-cause death (HR = 1.68, 95% CI 1.41‒2.00) compared with the counterparts. CONCLUSIONS: Elevated WWI levels were associated with a higher risk of cardiovascular mortality and all-cause mortality independently.