Secular growth changes in stature and weight for Chinese Mongolian youth, 1964-2005

Background: A secular growth trend has been demonstrated in China during the past half century. However, few studies have involved minority ethnicity. Aim: This study demonstrates secular changes in stature and weight for Chinese Mongolians from 1964 to 2005, and analyses the correlations with environmental factors, revealing inequalities within populations. Subjects and methods: Data were gathered from 7- to 18-year-old students in the Inner Mongolian Autonomous Region of China, both from local records in 1964 and from the 1985, 1991, 1995, 2000 and 2005 cycles of the Chinese National Survey on Students' Constitution and Health. Results: During the past 41 years, the average rates of stature increments for 7- to 17-year-olds are 1.9 and 2.0 cm per decade, of weight are 2.2 and 1.5 kg per decade and of BMI are 0.5 and 0.3 kg/m(2) per decade, for males and females, respectively. The overall increments of stature in 18-year-old males and females from 1985 to 2005 are 2.3 and 2.1 cm, respectively. The rate of change of stature is stronger in the first three decades, while that of weight and BMI are greater in the last decade. Evidence strongly suggests that changes may have occurred since the late 1970s. Conclusion: The positive growth changes of Chinese Mongolian people are closely related to urbanization, socio-economic progress and living improvements.