Long-term Changes in the Growth of Czech Children Population

Overview

Based on the results of six nation-wide anthropological surveys of children and adolescents and on the results of survey from year 1895 the analysis of secular trend of body height in children and adolescents in the Czech Republic (formerly the Czech countries of Czechoslovakia) was performed. The analysis is supplemented with data on body height of boys from Vienna Military Academy from the years 1800-1809. The growth data (year and sex specific height averages) were fitted by polynomial spline of 3rd order (with weighting derived from standard deviations and sample sizes).

The gradual increments of average body height of the Czech children population in age categories from 7 years to adult age is documented for boys since 1800, for girls from 1895. The greatest difference was noted for 15-year boys, where the body height increased by 30 cm over the last 200 years. Similarly, for girls the highest difference was noted for 12-year olds (18 cm between 1895 and 2001). Secular trend of body height slows down in the last decade, particularly for girls.

The period of the fastest growth, derived by differentiation of the fitted average growth curves shifts to younger age categories gradually. For boys, the period of maximum growth velocity moved from 16 to 13 years, while for girls from 11.5 to 11. Pubertal growth spurt location shift is probably connected to the sexual maturation timing changes. In the 1895, the mean age of menarche for girls was 15.6 years, whereas in 1991 and 2001, it was 13 years. The mean age of mutation for boys was 14.5 years in 1991 and it shifted to 13.8 years. This observation corresponds to a more prominent slow-down of the secular trend of body height in girls and a less prominent diminution in boys.

The 18 years old boys presently reach the average body height 180.1 cm, which means an increase of adult body height by 12 cm in comparison with the year 1895. The average age of present 18-year old girls is 167.2 cm, which is more then 10 cm higher than in 1895. In view of the changes of socio-economics conditions there is not only a gradually increased body height, but the whole developmental phase of the individual to reaching adulthood speeds up.

Key words:
body height, secular trend, growth velocity, maturation