Aim: The aim of the present study was to investigate the prevalence rate of overweight and obesity in a nationwide survey of fourth- and eighth-grade Norwegian schoolchildren, the changes in overweight rates among eighth graders from 1993 to 2000, and to investigate factors associated with overweight.
Methods: Cross-sectional dietary surveys were conducted on nationally representative samples of eighth graders in 1993, and among fourth and eighth graders in 2000. Self-reported weight and height was available from 1,650 eighth graders in 1993, and from 664 fourth and 825 eighth graders in 2000. Data on dietary pattern, social class, and physical activity were also available.
Results: In 2000 the prevalence of overweight and obesity among the fourth graders was 18.5% and 3.6%, respectively, and among the eighth graders 11.5% and 1.8%, respectively. A marked increase in overweight and obesity among Norwegian eighth graders from 1993 to 2000 was observed; the prevalence of overweight and obesity increased by 4 and 0.9 percentage points, respectively. Social class, time spent watching TV or in front of a computer, and breakfast frequency were associated with the odds of being overweight. An inverse relation between intake of sweets and overweight was observed. Validation studies demonstrated a high correlation between self-reported and measured height and weight in both age groups.
Conclusion: The present study demonstrates a high prevalence of overweight and obesity among schoolchildren, especially among fourth graders in Norway. Moreover, the proportion of overweight and obese children has increased greatly among eighth graders during the last decade.