Background: Time trends in overweight, obesity and underweight among 10-year-old children were investigated between 1999 and 2003 with attention to gender and areas with different socioeconomic status (SES).
Material: The study was performed in Stockholm County, where schools within eight different SES areas were randomly sampled. In selected schools, data on height and weight were abstracted from school health records of 2416 ten-year-old boys and girls examined by school nurses in 1999 and 2183 examined in 2003.
Results: Among boys, the prevalence of overweight was 21.6% in 1999 and 20.5% in 2003 (difference -1.1% (95% confidence interval (CI), -4.6; 2.4)) and for obesity 3.2 and 3.8% (difference 0.6% (95% CI, -0.9; 2.2)). Among girls overweight decreased from 22.1 to 19.2% (difference -2.9% (95% CI, -6.3; 0.6)) and obesity from 4.4 to 2.8% (difference -1.6% (95% CI, -3.1; 0.0)). There was a marginally significant difference in obesity trends in girls versus boys (P=0.051). The prevalence of underweight decreased nonsignificantly both in boys and in girls. Strong gradients, with more obesity and overweight in socioeconomically disadvantaged areas, were observed in both genders in 2003. Differences between SES areas were also seen in 1999 but were more pronounced in 2003. Among boys divergent trends in obesity were observed between 1999 and 2003, with evidence for increases in less affluent areas only.
Conclusion: This population-based study of 10-year-olds indicates that rates of obesity, overweight and underweight are stable in Stockholm County. However, obesity is more prevalent in relatively less advantaged SES.