Overweight among young people in Sweden is increasing. The aim of the present study was to investigate the frequency of overweight and obesity based on body mass index (BMI) values among children and adolescents. Overweight was defined as a BMI value > or = 91st percentile and obesity as a BMI value > 98th percentile on an international reference BMI curve. The study population included boys and girls from four age groups: 9, 12, 15 and 18 y. The data consisted of self-reported measures of height and weight that were obtained from questionnaires used in a cross-sectional study in December 1997. A validation study was performed using a part of the study population. A total of 7011 (81.7%) participants completed the questionnaire. The correlation between self-reported estimations and objective measures of height and weight was high in the oldest age groups (0.88-0.98), but lower in the 9-y-old age groups (0.37-0.72). These self-reported estimations in the 9-y-olds were excluded from further analysis. It was found that 12.3%, 11.6% and 11.4% of the boys in the 12-, 15- and 18-y-old age groups and 6.8%, 5.5% and 4.8% of the girls in the same age groups were overweight and 7.9%, 8.9% and 7.3% of the boys and 5.1%, 4.2% and 3.9% of the girls were obese.
Conclusion: The prevalence of overweight and obesity was found to be high in the study population and is a serious public health problem. The prevalence of obesity was significantly higher (p < 0.05) in 15-y-old boys living in rural areas than in city and town dwellers of the same age.