Confirmation of physical growth pattern in children with a slim body type: analysis of longitudinal data in Korean youth

Abstract

There is little research carried into physical growth in obesity, and there is even less carried out into physical growth in slimness. In this study, using data on Koreans, who are racially similar to Japanese, we classified subjects into slim and medium types, and analyzed longitudinal growth data for height and weight in these two groups. The study groups comprised 600 boys and 501 girls in the final year of high school selected from schools in Busan, South Korea, and in a suburb of Busan. We identified the age at maximum peak velocity (MPV) in growth during puberty derived from the growth velocity curves for height using the wavelet interpolation method, and determined the levels of maturity. We also retrospectively analyzed the rate of appearance of the slim and moderate types back to the first year of elementary school, and investigated genetic elements by examining the proportion of slim children who remained slim. The proportions of boys and girls classified as slim in grade 1 were 26% and 38%, respectively, in relation to those classified as slim in the final year. The ages at MPV for height were 14.11 years (SD 1.07) among medium-type boys and 14.68 years (SD 1.01) among slim boys. The ages at MPV for height were 12.05 years (SD 1.30) among medium-type girls and 12.18 years (SD 1.36) among slim girls. The ages at MPV for height were significantly different (P < 0.05) between slim and medium-type boys, but were not significantly different in girls.