Prevalence of underweight, overweight and obesity on the basis of body mass index and body fat percentage in Hungarian schoolchildren: representative survey in metropolitan elementary schools

Abstract

Backgrounds/aims: The incidence of obesity is increasing dramatically not only among adults, but also in children. The purpose of the survey was to assess the age- and gender-specific anthropometric data of children between the ages of 7 and 14 years who attended elementary schools in Budapest.

Methods: A cross-sectional study was performed in 2005. Altogether 1,928 students (1,002 boys and 926 girls) were recruited from the schools. The representative sampling sites were selected randomly. Height and waist circumference were measured, other data were analyzed by an 8-polar bioelectrical impedance procedure. Statistical analysis was carried out using SPSS 11 for windows.

Results: On the basis of body mass index (BMI), prevalence of underweight, overweight and obesity were 5.1, 18.1 and 7.4% for boys and 6.8, 19.6 and 6.3% for girls, respectively. On the basis of body fat percentage (%BF), prevalence of obesity was 17.9% for boys and 12.8% for girls. Forty nine percent of boys and 28% of girls categorized as overweight by BMI were obese according to their %BF. The difference in waist circumference between individuals categorized by BMI as normal and obese was 24.7 cm for boys and 20.5 cm for girls. Between those categorized as non-obese and obese by %BF, the difference was 17.3 cm for boys and 16.4 cm for girls. Normal and overweight boys and girls with high %BF had significantly higher waist circumferences than their counterparts with normal %BF. This means that many obese children may escape detection as obese, if classified as overweight on the basis of BMI alone.

Conclusion: Results appear to underline that in addition to BMI, the determination of the %BF and waist circumference is important in epidemiological studies to identify obese subjects.