Obésité en Suisse: percentiles d'indice de masse corporelle (IMC) d'une population d'enfants et d'adolescents nés en 1980 à Lausanne et écart avec les normes suisses (1955)

Summary

¶Obesity in Switzerland: percentiles of body mass index of a cohort of children and adolescents born in 1980 in Lausanne and differences with the Swiss percentiles calculated for boys and girls in 1955¶Objectives: The objective of this study is to calculate the percentiles of BMI of a cohort of 1203 children and adolescents, representing the 95% of the pupils of the school, born in 1980 followed longitudinally between 5 and 16 years. We compare these percentiles with those of the first swiss study, calculated on a cohort born in 1954–1956.¶Methods: The percentiles were calculated with the method of Cole, on the basis of weight and height measured during the controls by the school health service, at a non-periodic mean intervall of 14 months.¶Results:The gap between the BMI percentiles of the two cohorts is near zero for the third percentiles, weak but progressively growing with age up to two units of BMI for the 50th percentiles. For the percentiles 97 the difference, straight away present at five years, grows regularly up to 11 years, and remains thereafter for the girls at 4.3 units of BMI, while growing more up to 6.8 units of BMI at 15 years for the boys. The percentages of children and adolescents of the present study with overweight, in accordance with the thresholds of Cole, constant for the girls at 14%, increase for the five to 11.5 years old boys from 13.4% to 17.6% for the 11.5 to 16 years old. The percentage of obesity is 2.7% for the girls, and increase for the same categories for the boys from a percentage of 1.7% to 2.3% for the boys.¶Conclusions:The changes during this quarter of century are important, especially for the boys. We can postulate thereafter a very early change in the energy balance. A chronic increase of the food supply, linked or not with a decrase of the physical activity, would be an explanation.