Transition from preclinical obesity to clinical obesity among US adults: incidences and risk factors.

Abstract

Background: The Lancet Diabetes & Endocrinology Commission redefined obesity by considering both anthropometric and direct measures of adiposity, in addition to body mass index (BMI), and distinguishing preclinical from clinical obesity based on physical function and related conditions. However, the frequency and determinants of progression from preclinical to clinical obesity have never been studied.

Methods: We included participants with no obesity, preclinical obesity, or clinical obesity from the All of Us dataset. Obesity was defined as meeting at least two of the following four criteria: (1) BMI ≥ 30 kg/m², (2) waist circumference ≥88 cm for females or ≥102 cm for males, (3) waist-to-hip ratio (WHR) > 0.85 for females or >0.90 for males, and (4) waist-to-height ratio (WHtR) > 0.50, or BMI ≥ 40 kg/m². Baseline preclinical or clinical obesity was determined based on self-reported physical function and obesity-related conditions. Transition from preclinical to clinical obesity was defined based on the new onset of related conditions over follow-up. We estimated cumulative transition incidences from preclinical to clinical obesity and evaluated risk factors for transition using time to transition and Cox models after multivariable adjustment.

Results: Among 319,815 participants, 28.9% had preclinical obesity and 40.0% had clinical obesity at baseline. Of the 92,396 individuals with preclinical obesity, 24,057 (26.0%) transitioned to clinical obesity over a median follow-up of 2.9 years. The cumulative incidence at 1, 3, and 5 years was 12.7%, 25.7%, and 34.3%, respectively. In the adjusted Cox model, older age, elevated hemoglobin A1C, higher BMI, higher WHR, higher WHtR, insurance coverage, and poorer self-reported overall health were strongly and independently associated with a greater likelihood of transition.

Conclusions and relevance: Progression from preclinical to clinical obesity is relatively common. Given the different treatment considerations proposed for preclinical and clinical obesity under the Lancet framework, improved identification of individuals at higher risk of progression may be important for future implementation of this classification system.