In this study, we transversely and longitudinally analyzed changes in height, body weight, and the body mass index (BMI) in male and female students aged 15 to 20 years over the past 20 years. In both the boys and girls, the body weight, BMI, and standard deviation increased yearly, and this increasing tendency between 5 and 95%ile values was noted in all age groups. Furthermore, the rates of increase in the 95%ile values of the body weight and BMI in the girls were greater than in the boys. Concerning serial changes in the difference between 15 and 19 years of age, the boys' height decreased. In the girls, the 5%ile values of height decreased, and the mean and 95%ile values of body weight increased. Thus, the proportions of obese persons with a BMI of 24 to 28 increased yearly in both the boys and girls, suggesting height prematurity before 15 years of age in boys and a diverse physical status in girls.
