To evaluate the prevalence of overweight among school children at urban and rural area and also examine the difference of body fat compositions of normal and overweight status children in Taiwan.
We conducted school-wide survey among junior-high school children at Taipei (as urban area) and Taitung (as rural area) in 2006 and 2012. Anthropometric variables of body height and weight were measured using standard scales and BMI was calculated as kg/m2. We measured body composition using the Tanita body composition analyzer (TBF-410GS). Total body fat (TBF) and percentage of body fat (%BF) were obtained for further analyses.
There are 1263 urban and 577 rural children included for this survey. The mean (SD) of BMI for boys was 21.6 (4.2) at urban and 21.0 (4.2) at rural area and for girls was 20.5 (3.5) and 20.3 (3.4) at urban and rural area (no statistical difference). But the percentage of body fat was 22.2 (7.9) and 18.9 (6.9) for urban and rural boys (p < 0.001), and was 26.2 (7.8) and 24.5 (7.1) for urban and rural girls (p< 0.01).
The overall prevalence of overweight was 38.3% in boys and 24.6% in girls for urban children and was 30.4% and 20.5% for rural children. The prevalence of overweight was 41.7, 37.1 and 35.8 for age 13, 14 and 15 yo urban boys and was 33.3, 33.7, and 25.2% for rural boys. For girls, the prevalence of overweight was 23.5, 25.8 and 24.6 for age 13, 14 and 15 yo at urban area was 28.1, 20.9, and 17.1% at rural area.
There is no statistical difference of mean BMI between urban and rural area (26.0 vs. 26.3 for boys and 25.4 vs. 25.4 for girls). However, the percentage of body fat was higher for urban overweight children when compared with rural overweight children (28.8 vs. 26.5 for boys, p<0.05 and 36.5 vs. 32.9 for girls, p<0.001).
Using BMI as cot-off points of overweight for children at urban and rural area may be biased (or underestimate for the urban children). Body fat composition may be more appropriate criteria for children or for children comparing with different areas or countries.