Background: Individual traditional anthropometric measures like body mass index (BMI) and waist circumference may not fully capture the relation of adiposity to mortality. Investigating multi-trait body shapes could overcome this limitation, deepening insights into adiposity and mortality. Methods: Using UK Biobank data from 462,301 adults (40-69 years at baseline: 2006-2010), we derived four body shapes from principal component analysis on BMI, height, weight, waist and hip circumference, and waist-to-hip ratio. We then used multivariable-adjusted Cox proportional hazard models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for associations between body shapes and mortality for principal component scores of +1 and -1. Results: During 6,114,399 person-years of follow-up, 28,807 deaths occurred. A generally obese body shape exhibited a U-shaped mortality association. A tall and centrally obese body shape showed increased mortality risk in a dose-response manner (comparing a score of +1 and 0: HR=1.16; 95% CI=1.14-1.18). Conversely, tall and lean or athletic body shapes displayed no increased mortality risks when comparing a score of +1 and 0, with positive relations for the comparison between a score of -1 and 0 in these shapes (short and stout shape: HR=1.12, 95% CI=1.10-1.14; non-athletic shape: HR=1.15, 95% CI=1.13-1.17). Conclusions: Four distinct body shapes, reflecting heterogeneous expressions of obesity, were differentially associated with all-cause and cause-specific mortality. Multi-trait body shapes may refine our insights into the associations between different adiposity subtypes and mortality.
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