Normal Weight Obesity and Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis

To estimate the overall prevalence and absolute burden of overweight and obesity in the world and in various regions in 2005 and to project the global burden in 2030. Pooling analysis. We identified sex- and age-specific prevalence of overweight and obesity in representative population samples from 106 countries, which cover approximately 88% of the world population, using MEDLINE and other computerized databases, supplemented by a manual search of references from retrieved articles. Sex- and age-specific prevalence of overweight and obesity were applied to the 2005 population to estimate the numbers of overweight and obese individuals in each country, each world region and the entire world. In addition, the prevalence, with and without adjusting for secular trends, were applied to the 2030 population projections to forecast the number of overweight and obese individuals in 2030. Overall, 23.2% (95% confidence interval 22.8-23.5%) of the world's adult population in 2005 was overweight (24.0% in men (23.4-24.5%) and 22.4% in women (21.9-22.9%)), and 9.8% (9.6-10.0%) was obese (7.7% in men (7.4-7.9%) and 11.9% in women (11.6-12.2%)). The estimated total numbers of overweight and obese adults in 2005 were 937 million (922-951 million) and 396 million (388-405 million), respectively. By 2030, the respective number of overweight and obese adults was projected to be 1.35 billion and 573 million individuals without adjusting for secular trends. If recent secular trends continue unabated, the absolute numbers were projected to total 2.16 billion overweight and 1.12 billion obese individuals. Overweight and obesity are important clinical and public health burdens worldwide. National programs for the prevention and treatment of overweight, obesity and related comorbidities and mortalities should be a public health priority.

Background: The rising prevalence of obesity represents an important public health issue. An assessment of its costs may be useful in providing recommendations for policy and decision makers. This systematic review aimed to assess the economic burden of obesity and to identify, measure and describe the different obesity-related diseases included in the selected studies. Methods: A systematic literature search of studies in the English language was carried out in Medline (PubMed) and Web of Science databases to select cost-of-illness studies calculating the cost of obesity in a study population aged ≥18 years with obesity, as defined by a body mass index of ≥30 kg/m², for the whole selected country. The time frame for the analysis was January 2011 to September 2016. Results: The included twenty three studies reported a substantial economic burden of obesity in both developed and developing countries. There was considerable heterogeneity in methodological approaches, target populations, study time frames, and perspectives. This prevents an informative comparison between most of the studies. Specifically, there was great variety in the included obesity-related diseases and complications among the studies. Conclusions: There is an urgent need for public health measures to prevent obesity in order to save societal resources. Moreover, international consensus is required on standardized methods to calculate the cost of obesity to improve homogeneity and comparability. This aspect should also be considered when including obesity-related diseases.