Epidemiology and Natural History of Preclinical and Clinical Obesity: Insights From a UK Cohort

OBJECTIVE: Obesity has been traditionally defined by BMI alone, but this metric has limitations in assessing body fat composition and adiposity complications. The Lancet Diabetes and Endocrinology Commission (LDEC) issued a new obesity definition to address these challenges, stratified by preclinical and clinical groups. We evaluated the epidemiology of preclinical and clinical obesity in the UK Biobank and associations with incident cardiovascular disease (CVD). METHODS: We performed retrospective cohort analyses of 502,233 adults enrolled in the UK Biobank. Obesity was categorized using the new definition from LDEC. Clinical obesity was defined as adiposity-related dysfunction assessed via ICD10 codes, physical immobility, and abnormal laboratory values. Preclinical obesity had no additional metabolic deficits. RESULTS: The prevalence of preclinical and clinical obesity was 31.2% and 36.6%, and most were in the WHO overweight category. Clinical obesity was more prevalent in men, elderly, South Asians, and lower education or income level groups. Individuals with clinical obesity without baseline CVD had an increased hazard of incident stroke, heart failure, and myocardial infarction. CONCLUSIONS: In a large UK cohort, preclinical and clinical obesity were common, but the risk for incident CVD was elevated for those with clinical obesity.