Levels and Trends of BMI, Obesity, and Overweight at National and Sub-national Levels in Iran from 1990 to 2016; A Comprehensive Pooled Analysis of Half a Million Individuals.

Background: In developing countries like Iran, the burden of obesity increases through comorbid diseases. We estimated the mean body mass index (BMI) and prevalence of overweight/obesity by components of sex, age, province, and year in Iran from 1990 to 2016.

Methods: Through a comprehensive systematic review, all relevant data sources pooled results with individual level national and sub-national population-based studies. Two stages of age-spatio-temporal modeling and Gaussian process regression were used to estimate mean BMI, followed by estimation of obesity and overweight prevalence through the crosswalk modeling.

Results: In 2016, the age-standardized mean BMI was 27.9 (27.2-28.7) kg/m² in women and 25.9 (25.2-26.5) kg/m² in men. At the same time, the prevalence rates of overweight and obesity were 71.7% (67.9-75.8), and 36.8% (34.1-39.7) in females, and 57.1% (53.7-60.6), and 18.4% (16.9-20) in men. This shows a considerable increase from 1990 when the figures were respectively 24.4 (23.3-25.5) , 36.6% (32.2-41.5), and 8.2% (95% UI: 6.9-9.7) in women, and 23.5 (22.5-24.5), 30% (26.4-34), and 4.7% (4.0-5.5) in men, with 66% attributed to population growth.

Conclusion: Considering the increasing trends of BMI, Sustainable Development Goals (SDGs) seem far out of reach. We need to call for action, aiming for both weight loss strategies and controlling the comorbidities that mediate high BMI risk.