Two papers were extracted and pooled data from published sources were used to estimate the distribution of BMI values for adults living in many countries around the world. The NCD Risk Factor Collaboration and the Global Burden of Disease Study 2013 presented data for 200 and 188 countries, respectively. We extracted estimates from the two datasets for the prevalences of overweight and obesity in 28 Western countries. The two studies used similar methodology for extracting and pooling data, however the papers show serious discrepancies in several countries. Our analysis reveals the need for increased standardization of the identification and analysis of surveys of BMI distribution. This is necessary in order to facilitate comparability of study results and accurate global monitoring of obesity trends. Our findings also indicate that if findings from Western countries contain serious discrepancies, then findings from middle-income and low-income countries will likely have a poor level of accuracy as far fewer surveys of BMI distribution have been carried out.
Keywords: BMI; Errors in surveys; Obesity; Population surveys.