[Comparison of skeletal development between rural and urban school-age children]

Skeletal development and other related indicators were measured in 1680 children aged 7-18 in urban areas of Harbin and rural areas of Hailun County in 1990-1992, and comparisons were made. The results showed that the skeletal age of urban children aged 7-17 was higher than that of rural children in both sexes, and this difference was significant in the early puberty stage. The difference in mean values of cortical thickness of the metacarpals between urban and rural children showed similar tendency. Sesamoid ossification in urban children occurred one year earlier than that in rural children in both sexes. In primary school-age children, skeletal age was highly correlated with body height and weight. The development of secondary sex characteristics in both sexes and the age at menarche in girls in urban areas were earlier than those in rural areas, and the onset of puberty occurred one year earlier in urban than that in rural children.