Relationships among tempo of maturation, midparent height, and growth in height of adolescent boys and girls.

The influence of rate of skeletal maturation and midparent height on growth in height during adolescence was analyzed on longitudinal data for 184 boys and 166 girls from the Wrocław Growth Study. Seven biological parameters describing the shape of the growth curve in stature were derived from the Preece-Baines model 1 applied to individual serial data. Rate of skeletal maturation inferred from the difference between chronological and skeletal ages at 12 years in girls and 14 in boys. Principal components analysis of the biological parameters extracted three factors for boys and four for girls. The factors explained 90% and 97% of the total variance in boys and girls, respectively. The factors reflected attained size and the timing and intensity of the adolescent spurt in height. Multiple regression showed a high relationship between skeletal maturation rate, midparent height, and principal component scores. Three aspects of adolescent growth: size, timing, and intensity show an apparent sex difference. The timing and intensity of the spurt are highly affected by tempo of maturation in girls, but less so than in boys. It might suggest in girls a less efficient compensatory effect for reduced length of overall growth period in early maturers that increases height gain. Midparent height influences the size component during the spurt, thus adjusting the height parameters. The dependency between attained stature (height at take-off, PHV, and adult stature), timing, and initial intensity of the growth spurt of daughters and midparent height is greater than in sons.