Children who are breastfed longer are more likely to have a better understanding of language and a higher intelligence (IQ) later in life, a U.S. study said Monday. Previous studies support the relationship between breastfeeding and health benefits in infancy, but the extent to which breastfeeding leads to better cognitive development is less certain, according to researchers at the Boston Children\'s Hospital. The researchers studied more than 1,300 children born to women participating in a research project called Viva, which was designed to examine prenatal factors in relation to pregnancy and child health. Each of the children underwent a cognition assessment when they were 3 and 7 years old. \"We found that longer duration of breastfeeding and greater exclusivity of breastfeeding were associated with better receptive language at age 3 years and with higher verbal and nonverbal IQ at age 7 years,\" the researchers wrote in their paper in the journal JAMA Pediatrics. They reported a receptive language benefit at age 3 years of 0. 21 points per month from breastfeeding and an IQ benefit at age 7 years of 0.35 points per month on the verbal scale and 0.29 points per month on the nonverbal one. In other words, breastfeeding an infant for the first year of life would be expected to increase his or her receptive score by about 2.5 points and IQ by about 4 points. These researchers concluded that the findings \"support national and international recommendations to promote exclusive breastfeeding through age 6 months and continuation of breastfeeding through at least age 1 year.\" In an accompanying editorial, Dimitri Christakis of the Seattle Children\'s Hospital Research Institute, said that merely reiterating the importance of breastfeeding is clearly not enough. \"The problem currently is not so much that most women do not initiate breastfeeding, it is that they do not sustain it,\" Christakis wrote, \"In the United States about 70 percent of women overall initiate breastfeeding ... however, by six months, only 35 percent and 20 percent, respectively, are still breastfeeding.\" Christakis urged that workplaces should provide opportunities and spaces for mothers to use breast pumps and that breastfeeding in public should be \"destigmatized.\"