[Percentile curves on growth among breastfed 1-4 year olds in 8 urban areas]

Objective: To construct the growth percentile curves of weight-, length/height-, head circumference and BMI for 1 to 4 year-olds who had been breastfed in urban areas. Methods: Data was from the longitudinal study on 1 025 breastfed children aged 1 to 4 years, in 8 urban areas during 2008-2012. MLwiN2.25 was selected to construct the multi-level models of weight-for-age,length for-age, head circumference-for-age and BMI-for-age. The models included many growth relevant factors including gender, age, family and social demographic characteristics, perinatal factors, parent biological characteristics, dietary patterns and diseases of childen. Based on these models, predicted values (P(3), P(15), P(50), P(85), P(97)) were estimated to fit the percentiles reference curves. Results: The percentiles reference curves of weight-, length/height, head circumferenceand BMI-for-age for the 1-4 year-olds who had been breastfed in the urban areas were developed. Differences of all the indicators between boys and girls were statistically significant (P<0.001). Weight, length/height, head circumference and BMI were higher in boys than those in girls, with an average differences as 0.56-0.76 kg, 0.89-1.12 cm, 0.64-0.91 cm and 0.31-0.52 kg/m(2). Conclusion: The percentiles reference curves on growth, constructed by the longitudinal observational data and scientific method, were important in reflecting the development of breastfed children in urban areas.