[A longitudinal study of urban-rural growth differences among infants fed with breast milk in six economically better areas in China].

OBJECTIVE

To understand the differences between urban and rural breast-fed infants' growth patterns.

METHOD

In economically better regions of six provinces in China, 1147 urban and 1058 rural subjects were recruited by the project respectively, and their longitudinal weight, length, and head circumference were measured from birth to 12 months old. The monitoring frequency was 16 times in total. Analysis was conducted to compare the growth patterns between 497 of urban and 764 of rural subjects meeting the breast-fed babies definition by WHO.

RESULT

During the first year after birth, urban breast-feeding boys' weight, length, head circumference increased by 7.13 kg, 26.9 cm, and 12.4 cm respectively, and 6.60 kg, 26.1 cm, and 11.9 cm for girls. The corresponding values of rural population were 6.70 kg, 25.7 cm and 12.4 cm for boys, and 6.20 kg, 25.0 cm, and 11.8 cm for girls respectively. The gaps existed in the three physical indexes between urban and rural breastfeeding babies were 110 - 480 g, 1.2 - 2.0 cm and 0.1 - 0.6 cm for boys, and 200 - 510 g, 1.3 - 1.7 cm, and 0.4 - 0.6 cm for girls. In about 50% of monitoring age points, monthly increments of urban boy's weight presented higher than rural samples, but only 17% for girl's weight, and boy/girl's length and head circumference.

CONCLUSION

The urban-rural regional gaps in breast-fed infants' physical development were not optimistic and seemed to be wider in boys than in girls. There are still large room for improvement for growth of infants in rural areas.