Background: Recent evidence from several countries has emerged suggesting that the increase in the prevalence of childhood obesity has slowed down substantially, or even leveled off. Also in Switzerland this trend has been observed. In 2002, 20.3% and 19.1% of boys and girls, respectively, were overweight or obese in Switzerland. In 2007, the prevalence of overweight was significantly lower, with 11.3% and 9.9% of school-aged boys and girls, respectively, being overweight or obese. Further trend analyses are necessary to confirm that the stabilizing trend observed reflects a long-term change in the rates of childhood overweight and obesity.

Objective and Methods: The aim of the present study is to repeat the 2002 and 2007 national studies, in order to monitor the trend in the prevalence of overweight and obesity in 6-12 year old children in Switzerland during this 5 respectively 10 year time period. Height and weight will be measured and used to calculate body mass index (BMI). BMI references form the Centers for Disease Control and Prevention will be used to determine the prevalence of underweight (< 5th percentile), overweight (≥ 85th and < 95th percentile) and obesity (≥ 95th percentile). Waist and hip circumference will be measured. Moreover, skinfold thicknesses and bioelectrical impedance analysis will be performed to calculate body fat percentage.

Inclusion Criteria:

• age 6-12 years
• child is attending one of the selected classrooms

Exclusion Criteria:

• age below 6 or above 12 years

3 classrooms each from 60 randomly selected schools