Cognitive and growth comparison between breastfed and formula fed infants at six and nine months of age

This study examined the relation between duration of breastfeeding, cognitive development, and growth of infants between three and nine months of age. The design of the study was longitudinal and observational. Participants were from a rural community in Oklahoma. Data was collected using a demographic questionnaire, infant anthropometric and visual habituation variables. The final analysis was on 111 infants who were predominantly breastfed at three months of age. Of the 111 infants, 73% were still breastfed at nine months, 12% stopped breastfeeding between six and nine months and 15% stopped breastfeeding between three and six months. General linear modeling was used to assess the interaction between growth and visual habituation with breastfeeding duration groups over the nine-month study period. Analyses found no significant interaction between breastfeeding duration groups and visual habituation over time. Changes in weight-for-age z score were significantly less for those infants who were breastfed for the entire nine months than for those that stopped before six months of age (p = 0.012). When length-for-age at three months was used as a covariate there was a significant interaction between change in length z score and breastfeeding group over time (p = 0.026). However, there was no relationship between breastfeeding duration groups and changes in BMI z score over time (p = 0.537). In conclusion, over the short time period (three to nine months) duration of breastfeeding did not have any impact on cognitive development as evidenced by visual habituation, but small differences were seen in changes in weight and length z scores. The effect of breastfeeding in all of these variables may become more evident in additional longitudinal studies. This project was supported by National Research Initiative Grant 2008-35200-18779 from the USDA National Institute for Food and Agriculture.