Analysis of linear growth during puberty

Linear growth was analysed in 438 boys and 483 girls aged from 6 years to 17 years. Annual records of each subject were fitted by using a cubic spline function. Parameters characterizing the growth process, such as peak height velocity (PHV), age at PHV, and age at onset of the pubertal growth spurt (PGS), were calculated directly from the estimated curves. The mean age at PHV was 11.2 years in girls and 13.0 years in boys. The mean PHV was 8.7 cm/year in girls and 10.3 cm/year in boys. Age at PHV showed a significant negative correlation with PHV and total pubertal gain, and a significant positive correlation with height at onset of the PGS, age at onset of the PGS and height at PHV. When subjects were divided into three groups (early, average and late pubertal maturation) according to the age at PHV, no significant difference in mean final height was seen between these groups, though a significant difference in height was observed at 6 years of age. When the results were adjusted for the difference in height at 6 years, the age at PHV showed a significant positive correlation with final height. It is concluded that age at PHV influences the final height.