Dynamic anthropometric changes in children as shown by longitudinal data for 2004–2009 from the city of Dalian, China

The physical development of children and adolescents always attracts widespread attention in society.The goal of the present study was to systematically analyse the dynamic changes in some anthropometric characteristics among primary school age children.Using a longitudinal study design, this study monitored physical growth annually in 933 pupils of Dalian, China, from 2004-2009.Longitudinal multi-level modelling (mixed model) was used to analyse the trajectory of growth from ages 7-12 years by gender. Height, weight and BMI were transformed into Z-scores relative to the WHO 2007 references.Height, weight and BMI were all higher for boys than for girls. Due to the interaction of age and gender, boys and girls exhibited different growth models. Average heights and weights for children of 7-12 years old in Dalian were higher than the WHO 2007 references. BMI z-scores for boys were significantly greater than the WHO 2007 references.Height, weight and BMI z-scores among boys and girls of 7-12 years old in Dalian were generally greater than the WHO standards. The major reasons for the differences may be due to rapid socioeconomic development and improvements in nutrition and living conditions.