Obesity in 4-year-old children more prevalent in girls and in municipalities with a low socioeconomic level

Aim: To provide updated prevalence data of BMI and obesity in 4-year-old Swedish children, also exploring socioeconomic differences. Subjects: A total of 4407 children born 1998-1999 (2231 boys and 2176 girls) in the county of Vasterbotten, Sweden. Methods: Overweight and obesity was estimated using the International Obesity Task Force cutoff values (ISO BMI). Information about socioeconomic level of the municipalities was collected from a health survey of the adult population. Results: Of the boys, 16.7% were classified as overweight and 3.1% of these as obese. Corresponding figures for girls were 22.1% and 4.5%. The P50 and P95 values for BMI were 16.2 and 18.8 for boys and 16.1 and 19.3 for girls, respectively. P50 was at the same level as in previous Swedish studies, while P95 was higher in this study. Obesity, in girls, was more prevalent in municipalities with a low socioeconomic level. Conclusion: Overweight and obesity in pre-school children in Sweden is more prevalent in girls than in boys, and the prevalence is as high as in school age children. A low socioeconomic level of living area seems to be related to a higher prevalence of obesity. Increased preventive efforts, both on the individual and the societal level, must be undertaken to reduce future health risks in obese children.