Secular changes are different in distinct subgroups of the growing population

The change of living conditions in East Germany after the German reunification in 1990 led to intensive secular changes in growth and development. Anthropometric data of height, weight, BMI and thickness of the subcutaneous fat layer are compared from two cross-sectional samples of German children and adolescents aged 6 to 18 years. The first sample was measured around 1989 and the second 10 years later around 1999. Both samples contain children and adolescents from the urban as well as from the rural population. The secular changes reported here are based on the comparison of medians of height, weight, BMI and subcutaneous fat layer thickness calculated for yearly age categories. Subsequently, medians of the 10% border categories are compared. These border categories contain the 10% smallest, lightest, slimmest or leanest subjects and the 10% tallest, heaviest, most corpulent or most obese subjects respectively of a yearly age category. The young generation shifted between 1989 and 1999 to a taller stature in the small as well as in the tall category. The secular pattern of measurements, which mark corpulence, is sex-specific and differs from that of length measurements. In general the light or lean subjects changed only little, however, there are clear age- and sex-specific changes in the upper border categories. Weight and BMI increased markedly in the upper border categories in young preadolescent children, but did not change much in adolescent boys of these category aged 15 and 16 and decreased in adolescent girls. Also the subcutaneous fat layer increased in the upper border category in preadolescent children, but decreased in adolescent boys and girls.