[Smoothed skeletal maturity curve of Japanese children by Tanner-Whitehouse 2 (TW2) method and its application]

This paper reports the TW2 skeletal maturity status on some 8,800 Ogi schoolchildren aged 6.5-17.5 years, who participated in the 1979-1988 Ogi Longitudinal Growth Study. The smoothing B-spline function was applied to 3, 10, 25, 50, 75, 90, and 97 percentile TW2 RUS, carpal and 20-bone scores. The carpal maturity pattern was variable throughout the periods. The RUS matured with narrower variation during preadolescent period, then became variable with advancing age. The dispersion of the 20-bone score converged toward post-adolescent period. Ogi children showed retarded skeletal maturation compared with British standard during preadolescent period, then the children have surpassed the standard at adolescence. The skeletal maturity status of Ogi children was not identical with that of two Chinese samples. Harbin and Beijing children. Ogi girls showed similar maturity pattern to Harbin girls, but Ogi boys retarded in the RUS score compared with Harbin boys during preadolescent period. Ogi girls retarded in the TW2 20-bone bone age at ages 7-9 years, then they surpassed Beijing girls. Ogi boys always exceeded Beijing boys during the period of 7-17 years. Tokyo children in 1960s surpassed the Ogi children during whole periods studied. Tokyo children in 1980s exceeded Ogi children only at postadolescent period in boys, and they retarded during adolescent period in girls. I examined a possible secular change in the skeletal maturation with a cohort analysis of Ogi children. The median test revealed the secular change only at the specific cohorts and age classes, but not general secular trend of acceleration of the skeletal maturation. I examined the socioeconomic influence to the skeletal maturation within Kyushu populations, Naze, Nomozaki and Ogi children. Although Ogi and Naze samples showed similar socioeconomic status, their skeletal maturity status differed significantly. Ogi and Nomozaki children showed similar skeletal maturity pattern irrespective of their socioeconomic discrepancy.