Dr. Mandy B. Belfort of Boston Children's Hospital and colleagues examined the relationships of breastfeeding duration and exclusivity with child cognition at ages 3 and 7. Researchers used assessment tests to measure cognition -- attention, memory, producing and understanding language, learning, reasoning, problem solving and decision making.
"Longer breastfeeding duration was associated with higher Peabody Picture Vocabulary Test score at age 3 and with higher intelligence on the Kaufman Brief Intelligence Test at age 7," the researchers said.
However, the study found breastfeeding duration was not associated with Wide Range Assessment of Memory and Learning scores.
"In summary, our results support a causal relationship of breastfeeding in infancy with receptive language at age 3 and with verbal and non-verbal IQ at school age," the study authors wrote in the study. "These findings support national and international recommendations to promote exclusive breastfeeding through age 6 months and continuation of breastfeeding through at least age 1 year."
The findings were published in the Journal of the American Medical Association Pediatrics.