Clinical obesity and all-cause and cancer-specific mortality in the UK Biobank

In January 2025, the Lancet Diabetes & Endocrinology Commision proposed a new definition of obesity that uses objective measures of body size to identify excess adiposity rather than body mass index alone. The framework further distinguishes between clinical obesity, defined as excess adiposity and objective signs and symptoms of obesity-related illness, and preclinical obesity, defined as excess adiposity without obesity-related illness. Researchers from the University of Regensburg (Germany) and the International Agency for Research on Cancer (Lyon, France) evaluated the association between this new obesity definition and mortality in the UK Biobank (502,134 participants from 2006 to 2010). For all-cause mortality, compared to no obesity, preclinical obesity (HR 1.18; 95% CI 1.14-1.23) and clinical obesity (1.56; 1.50-1.63) were associated with higher mortality. For cancer mortality, compared to no obesity, preclinical obesity (HR 1.18; 95% CI 1.13-1.24) and clinical obesity (1.25; 1.17-1.33) also were associated with higher mortality. Findings were consistent among sexes, among never-smokers, and after excluding the first 2 years of follow-up.