Velocities for the Tanner-Whitehouse 2 skeletal maturity in northwest Japanese children

This report describes the velocity of the Tanner-Whitehouse 2 skeletal maturity for some 6,300 Japanese children from Ogi Growth Study 1979-1988. The cubic B-spline function fitted the velocities for the Carpal, RUS and 20-bone scores on the smoothed velocity curves. The maturity velocity curves showed single peak around the adolescent period exclusive of a bimodal curve for girls' RUS velocity. Its first peak appeared at 10.9 years and the second, 13.9 years. Just after the first peak their height reached the maximal velocity (11.0 years). The RUS velocity curve for the boys showed the peak maturity velocity at 15.6 years. Their height attained the peak velocity (at 12.9 years) before the RUS maturity did. Although the Japanese children matured earlier for the RUS maturity than Europeans, it was comparable to that of other Asians. The study also showed that the skeletal maturation affected the height growth during the duration of height spurt for the boys, but only during the accelerating period for the girls.