Relationship between body composition and BMI in preschool children

Childhood obesity is one of the most serious public health challenges of the 21st century. Obesity is a state in which body fat accumulates to an abnormal degree, and detailed information about body composition is necessary to investigate the problems of obesity in children. In the present study, we measured body composition using equipment based on the multifrequency bioelectrical impedance analysis method to measure lean body mass and the quantity of fat. We evaluated differences in body composition in young children from 3 to 5 years old, including differences in relation to gender, and correlated them with measured values of BMI. The fat percentages in girls were higher than in boys, and the muscle percentages (muscle mass/weight × 100) were the opposite. These results show that there were differences in relation to gender. Our evaluations were based on regression analysis of fat percentages in relation to BMI and muscle percentages. A high correlation was found between BMI and fat percentage. The relationship between BMI and muscle percentage was the opposite of the relationship between BMI and fat percentage, and there was a high negative relationship between boys and girls. A significant regression tendency was confirmed from the results of the regression analysis of fat and muscle percentages for BMI in preschool children. This suggests that BMI can also be used to evaluate the fatness or thinness of a preschool child. In short, BMI can be used as an index that can be used to evaluate fat and muscle percentages from early childhood.