The European Childhood Obesity Group (ECOG) project: the European collaborative study on the prevalence of obesity in children.

During the European Congress on Obesity held in Barcelona in 1996, the European Childhood Obesity Group (ECOG) proposed a study designed to estimate the prevalence of obesity by country. An overview of existing systems revealed that most countries have no suitable structure in place for the determination of obesity in children and that the most practical sources of samples would be the school systems. A protocol was drawn up for these countries, whereas for those countries already collecting data, guidelines were defined to clarify the criteria allowing inclusion in the common analysis. The target population is 7-9-y-old children. The study design consists of separate cross-sectional population studies by country with a cluster probability sample of 2000 children attending primary school. The minimum common data will be age, weight, height, and hip, thigh, and waist circumferences. The participating countries will be encouraged to collect harmonized data on social indicators, lifestyle, diet, physical activity, and anthropometric measures of the parents. Children will be measured either by centrally based traveling examiners or, in countries with limited resources, by local staff. Each country will computerize its own data and send a copy to a center responsible for the common analysis. The main analysis will be of body mass index distribution in children from the different populations and determination of the proportion of children with a BMI above the 90th percentile of a common reference population. Members of the ECOG in 14 European countries have confirmed their interest in the project.