Economic costs of obesity: a systematic review

Introduction: Obesity is a growing public health problem leading to substantial economic impact. This study aimed to summarize the economic impact of obesity and to critically analyze the methods used in the cost-of-illness (COI) studies on obesity. Methods: We conducted systematic search in PubMed and Scopus from September 1, 2016, to July 22, 2022. Original COI studies estimating the economic cost of obesity and/or overweight in at least one country, published in English were included. To facilitate the comparison of estimates across countries, we converted the cost estimates of different years to 2022 purchasing power parity (PPP) values using each country’s consumer price index (CPI) and PPP conversion rate. Results: Nineteen studies were included. All studies employed a prevalence-based approach using Population Attributable Fraction (PAF) methodology. About half of the included studies (53%) were conducted in high-income countries while the others (47%) were conducted in middle-income countries. The economic burden of obesity ranged between PPP 15 million in Brazil to PPP 126 billion in the USA, in the year 2022. Direct medical costs accounted for 0.7% to 17.8% of the health system expenditure. Furthermore, the total costs of obesity ranged from 0.05% to 2.42% of the country’s gross domestic product (GDP). Of the seven studies that estimated both direct and indirect costs, indirect costs accounted for the largest portion of five studies. Nevertheless, a variety in methodology across studies was identified. The number of co-morbidities included in the analysis varied across studies. Conclusions: Although there was a variety of methodologies across studies, consistent evidence indicated that the economic burden of obesity was substantial. Obesity prevention and control should be a public health priority, especially among countries with high prevalence of obesity.