Health professionals who monitor the growth of children are also involved in the early detection of overweight. Appropriate tools are required for this purpose.The study sought to identify predictive markers of the development of subsequent overweight using a simple set of criteria.A consecutive cohort was composed of 1424 grade 4 children in Aquitaine, France, aged 8-9 years. Body mass index (BMI) was calculated during school health assessments at 8-9 years of age. Data from previous assessments at 3-4 and 5-6 years of age were also collected.Of the 189/1424 children (13.9 %) who were overweight according to the French national cut off for children aged 8-9 years, 67 (33.8 %) were already overweight at 3-4 years and 107 (54.1 %) at 5-6 years. Of the 134 (9.4 %) who were overweight at 5-6 years, 43.3 % were already overweight at 3-4 years and 79.9 % were overweight at 8-9 years. On the other hand, 76 of these 134 children (56.7 %) were not overweight at 3-4 years, so they had become overweight between the two assessments. The combination of the criterion "overweight at 3-4 years or 5-6 years" and "increase in BMI1kg/m(2) between 3-4 years and 5-6 years" appears to be the best predictor of the risk of overweight at 8-9 years, with good sensitivity (75.3 %) and specificity (87.9 %).A predictive tool based on BMI changes between ages 3-4 years and 5-6 years could be used for the early detection of the risk of developing overweight and obesity. The tool is easy to use, especially for health care in schools. Furthermore, the present findings confirm the value of following up and managing children who are already overweight between the ages of 3 and 6 years.
