Pubertal Growth and Sexual Maturation in Healthy Japanese Girls: Reference Values of Puberty After Cessation of Secular Trend and Relation Between Puberty and Growth

Abstract

Judging from the changes of height of school children, age at peak growth velocity, and age at menarche, the secular trend of growth and maturation ceased around 1990 in Japan. After the cessation of the secular trend, reference value of age at onset of puberty (Tanner stage 2 of breast development) is 9.74 ± 1.09 years and age at menarche is 12.24 ± 0.93 years in Japanese healthy girls. Diagnostic criteria for precocious puberty are 7 years and 6 months for the age at breast development and 10 years and 6 months for the age at menarche in Japan. There is a trend that onset of puberty occurs earlier in girls with greater height, greater height SDS, heavier weight, greater percent overweight, or greater BMI. The finding that girls with heavier 6-year-old weight have earlier onset of puberty and earlier menarche suggests that nutrition during infancy is associated with not only the onset of puberty but also the onset of menarche. The mean increase in the height from the occurrence of menarche to the age of 14 years was 6.6 ± 3.4 cm and was greater in girls with earlier menarche and smaller in those with later menarche. The mean height increase from the onset of puberty to the age of 14 years was 25.3 ± 5.7 cm and was greater in girls with earlier pubertal onset and smaller in those with later pubertal onset. When girls are the same height before puberty, a girl who enters puberty earlier than the other girl becomes shorter than the other girl at 17 years.