Obesity in Swedish schoolchildren is increasing in both prevalence and severity

To monitor and describe, on a national level, the development of body mass index (BMI), overweight, and obesity of schoolchildren in Sweden aged 7-18 years over a period of 8 years.

Longitudinal and cross-sectional studies of two nationally representative cohorts. A representative sample of 3,749 individuals from a birth cohort of 109,663 individuals born in 1973, and another representative sample of 3,158 individuals from a birth cohort of 94,064 individuals born in 1981; 4.5% and 1.6% of those born in 1973 and 1981, respectively, were missing from the sample. Data regarding height and weight from school health records.

From age 7-18 year, a strong positive secular change in BMI is found at all ages, and the rate of overweight and obesity is increasing for both boys and girls. Furthermore, obesity is growing more severe.

Nationally representative longitudinal BMI data for two cohorts, in which nonresponse bias is minimized, permitted monitoring and revealed a nationwide strongly positive secular change in BMI in Sweden, over a period of 8 years for individuals aged 7-18 years.