Cardiometabolic outcomes among adults with abdominal obesity and normal body mass index

Importance: Cardiometabolic disorders are the leading causes of death and disability worldwide, with abdominal obesity being a major contributor to these conditions. Data on normal-weight abdominal obesity and its association with cardiometabolic outcomes are limited. Objective: To investigate the global prevalence of normal-weight abdominal obesity and its association with cardiometabolic outcomes. Design, Setting, and Participants: This cross-sectional study used data from the World Health Organization Stepwise Approach to Surveillance of Noncommunicable Disease Risk Factors survey datasets between 2000 and 2020. The surveys were from 91 countries across Africa, the Americas, the Eastern Mediterranean region, Europe, Southeast Asia, and the Western Pacific region. Adults aged 15 to 69 years or 18 to 69 years (based on participating countries' national definitions of adult) were included. The data were analyzed between April 2024 and January 2025. Exposure: Normal-weight abdominal obesity, which is defined as a normal body mass index (BMI) of 18.5 to 24.9 (calculated as weight in kilograms divided by height in meters squared) but high waist circumference (female, ≥80 cm; male, ≥94 cm). Main Outcomes and Measures: The main outcomes were hypertension, diabetes, cholesterol, and triglycerides. Associations with these cardiometabolic outcomes were quantified using multivariable binary logistic regression models. Results: The study included 471228 participants (mean [SD] age, 40.4 [15.9] years; 57.8% female). Globally, 21.7% (95% CI, 21.5%-21.8%) of participants with a normal BMI had abdominal obesity, ranging from 15.3% (95% CI, 15.0%-15.7%) in the Western Pacific region to 32.6% (95% CI, 31.9%-33.3%) in the Eastern Mediterranean region. Lebanon had the highest prevalence of normal-weight abdominal obesity (58.4%; 95% CI, 54.1%-62.6%), while Mozambique had the lowest (6.9%; 95% CI, 5.9%-8.1%). Factors associated with abdominal obesity included primary and secondary or higher education (odds ratio [OR], 1.53 [95% CI, 1.50-1.57] and 2.38 [95% CI, 2.33-2.43], respectively), unemployment (OR, 1.25 [95% CI, 1.23-1.27]), low fruits and vegetables intake (OR, 1.22 [95% CI, 1.20-1.24]), and physical inactivity (OR, 1.60 [95% CI, 1.57-1.63]). Additionally, having a normal BMI and abdominal obesity was consistently associated with hypertension (OR, 1.29 [95% CI, 1.25-1.33]), diabetes (OR, 1.81 [95% CI, 1.72-1.90]), high total cholesterol (OR, 1.39 [95% CI, 1.35-1.44]), and high triglycerides (OR, 1.56 [95% CI, 1.48-1.64]). Conclusions and Relevance: In this cross-sectional study, more than 1 in 5 adults worldwide with a normal BMI had abdominal obesity. Relying solely on BMI may be insufficient to identify these high-risk individuals and provide timely interventions. The findings have implications for the United Nations' Sustainable Development Goal targets 2.2 (ending all forms of malnutrition) and 3.4 (reducing premature mortality from noncommunicable diseases).