[Association between feeding patterns and physical growth of late preterm infants aged 0-5 months of correction age]

To explore the relationship between feeding patterns and physical growth of late preterm infants with 34-36 weeks of gestational age and 0-5 months of correction age.

The data were from the project "Nutrition and Health System Survey and Application for Children aged 0-18 Years in China". Multi-stage stratified random sampling was used to conduct the study at 28 survey sites in 7 regions of East China, North China, Central China, South China, Southwest, Northwest and Northeast China from February 2018 to January 2020. A self-designed structured questionnaire for infants aged 0-6 months was used by the investigators to ask infant mothers or other primary guardians face-to-face to retrospectively collect the basic characteristics and feeding status of infants, and measure the length, weight and head circumference of infants. Based on inclusion criteria and exclusion criteria, a total of 48 late preterm infants fed exclusively breastmilk and 53 late preterm infants fed formula aged 0-5 months of correction age were enrolled in this study. Using the corrected age and gender of late preterm infants fed exclusively breastmilk as matching variables, 48 full-term infants fed exclusively breastmilk aged 0-5 months were matched by propensity score as reference to evaluate the difference in growth and development between late preterm infants and full-term infants fed exclusively breastmilk. Z-scores and weight gain rate were used to evaluate the growth and development of infants. ANOVA was used to compare the growth and development of infants in the three groups. Multiple linear regression was used to adjust for potential confusing factors to analyze the effects of different feeding patterns on the growth and development of late preterm infants.

There was no significant difference in length for age Z-score(LAZ), weight for age Z-score(WAZ), weight for height Z-score(WLZ), body mass index for age Z-score(BAZ) and weight gain rate between late preterm infants fed exclusively breastmilk and late preterm infants fed formula(P>0.05), and there was also no significant difference between late preterm infants fed exclusively breastmilk and full-term infants fed exclusively breastmilk(P>0.05). However, The WAZ and head circumference for age Z-score(HCZ) of late preterm infants fed formula were 0.41(P=0.03) and 0.44(P=0.02) higher than those of full-term infants fed exclusively breastmilk, but there was no significant difference in LAZ, WLZ, BAZ and weight gain rate between the two groups(P>0.05).

At 0-5 months of correction age, the growth and development of late preterm infants fed exclusively breastmilk were similar to that of full-term infants fed exclusively breastmilk. Formula supplementation may promote weight gain, but not length in late preterm infants.