[Changes on secular growth among minority girls in China from 1985 to 2005].

Objective: To analyze the trend of secular growth among the minority girls in China from 1985 to 2005 in order to develop national and local intervention strategies and measures to improve their physical fitness and health.

Methods: A total of 19 Chinese minority girls, including Mongolian, Hui, Zhuang, Korean, Tibetan, Miao, Buyi, Dong, Yao, Bai, Tujia, Hani, Dai, Lisu, Wa, Nakhi, Tu, Qiang and Salar were sampled from the 1985 and 2005 Chinese national surveys to study the students' physical fitness and health. Probit analyses were used to calculate age at menarche (AAM), and the heights and weights of 17-years-old girls in various minority groups.

Results: From 1985 to 2005, the increments of adult heights and weights increased significantly in many minority groups. The average height of girls aged 17 years old in each minority group had an increase of 150 cm in 2005. Ethnic groups with height growth rates of more than 1 cm per decade in girls aged 17 years old were Korean (1.47 cm/decade), Tujia (1.38 cm/decade), Qiang (1.32 cm/decade), Bai (1.25 cm/decade), Hui (1.13 cm/decade) and Buyi (1.07 cm/decade). And the minority ethics with weight growth rates of more than 1 kg per decade in girls aged 17 years old were Mongolian (1.79 kg/decade), Korean (1.69 kg/decade), Tibetan (1.66 kg/decade), Nakhi (1.39 kg/decade), Qiang (1.28 kg/decade) and Hui (1.10 kg/decade). The overall AAM showed a downward rate in all the 19 minority groups, but with different degrees. Tujia, Yao and Nakhi showed the largest reductions, with AAMs as 2.15, 1.76 and 1.38 years earlier in 2005 than in 1985, respectively.

Conclusion: Our data suggested that the downward secular trend in AAMs and the increments of adult heights might reflect the secular growth change in the major minority groups during the past 20 years, but there was an obvious disequilibrium of puberty development and increments of heights in adults between the minority groups.