Children who are exclusively breastfed for at least three months tend to be more cognitively advanced at school age, according to findings from the Promotion of Breastfeeding Intervention Trial (PROBIT).
In the PROBIT Study, 31 maternal hospitals and affiliated clinics in the Republic of Belarus adopted a programme supporting and promoting breastfeeding or continued their current practises and policies. More than 17 000 healthy newborns were enrolled between June 1996 and December 1997.
Significantly more infants born at the intervention hospitals were breastfed at three months (73 percent vs 60 percent), and remained so throughout their first year. The rate of exclusive breastfeeding was seven-fold higher in the intervention group at three months (43 percent vs six percent).
A total of 7 108 children in the intervention group and 6781 in the control group were assessed at an average age of 6,5 years.
The Wechsler Abbreviated Scales of Intelligence (WASI) showed statistically significantly higher average differences in the intervention group for vocabulary and verbal IQ, Dr. Michael S. Kramer, at McGill University in Montreal, and associates report in the Archives of General Psychiatry.
Teachers' academic ratings were also significantly higher for reading and writing among the children in the intervention group.
WASI scores were superior among children who had been exclusively breastfed and with increased length of breastfeeding, regardless of treatment group, as were ratings for reading, writing, and mathematics.
According to the authors, the differences in cognitive development may be due to constituents (such as essential polyunsaturated fatty acids) present at higher concentrations in breast milk than in formula, or may be related to the physical and social interactions inherent in breastfeeding.
"The consistency of our findings based on a randomised trial with those reported in previous observational studies should prove helpful in encouraging further public health efforts to promote, protect, and support breastfeeding," Kramer's team concludes.