Background: To date, there have been several reports about long-term changes in physical growth in children of different races around the world. However, limited studies on this change have been reported in Nanjing, China. We decided to assess long-term changes in body weight, length/height and head circumference in children (0-7 years old) in Nanjing over the past two decades from 1995 to 2015 and the relationship between socioeconomic development and the change of physical growth.
Methods: The results for body weight, length/height and head circumference in 0-to 7-year-old children were obtained from three repeated cross-sectional surveys that were performed by using the same methods in the same urban and suburban areas of Nanjing in 1995, 2005 and 2015. The differences in mean values between urban and suburban boys and girls and the increases per decade were compared. Socioeconomic indicators were collected and analysed.
Results: There was positive long-term growth in height and weight of children in Nanjing from 1995 to 2015, measurements increased 0.3-3.00 kg in weight and 1.0-3.8 cm in height for boys, 0.23-2.18 kg in weight and 1.3-3.6 cm in height for girls in urban areas (except children under 15 months), as well as 0.32-4.15 kg in weight and 1.1-7.4 cm in height for boys, 0.26-2.95 kg in weight and 1.2-6.3 cm in height for girls in suburban areas (except children under 8 months). Compared with the first decade, the changes of mean values in height and weight of urban children in the second decade were smaller. In contrast, the long-term change of suburban children still kept fast growth rate. Before 2.5 years old, negative increases in weight and height in urban children were observed in second decade. Urban-suburban difference of weight and height became smaller in 2015. The growth of head circumference from 1995 to 2015 underwent a small long-term change, especially of urban children.
Conclusion: The increased long-term physical growth due to rapid social and economic development would disappear, and genetic potential might have been seen.