Physical growth of children in urban, suburban and rural mainland China: a study of 20 years change.

OBJECTIVE: To describe secular trends on physical growth of children in China during the year of 1985-2005 and to analyze the urban-suburban-rural difference and its change.
METHODS: The measurements of height, weight and chest circumference obtained from two serial national cross-sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared.
RESULTS: The average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban-suburban difference in height had become smaller, and that in weight showed similar trend for children under 3 years old but became larger after 3 years old; the suburban-rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group.
CONCLUSION: Positive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio-economic development in China.