Body Shapes of Multiple Anthropometric Traits and All-cause and Cause-specific Mortality in the UK Biobank.

Background: Individual traditional anthropometric measures such as body mass index and waist circumference may not fully capture the relation of adiposity to mortality. Investigating multitrait 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 body mass index, height, weight, waist and hip circumference, and waist-to-hip ratio. We then used multivariable-adjusted Cox proportional hazard models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) 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; nonathletic shape: HR = 1.15, 95% CI = 1.13, 1.17).

Conclusion: Four distinct body shapes, reflecting heterogeneous expressions of obesity, were differentially associated with all-cause and cause-specific mortality. Multitrait body shapes may refine our insights into the associations between different adiposity subtypes and mortality.