A study has found that breastfed babies could have higher intelligence score in adulthood. The study published on Monday in The Lancet medical journal examined the development of about 3,500 newborns over three decades.

As per the study, the socioeconomic status of mothers also has impact on the results of breastfeeding. Bernardo Lessa Horta, a researcher from the Federal University of Pelotas in Brazil and lead author of the study, said in a statement that the breastfeeding effect on the development of brain and child intelligence is well established.

According to researchers of the study, they could not find whether the effects of breastfeeding remain in adulthood and whether socioeconomic status of a mother could play a crucial role in her choice to breastfeed or not. As per Horta, the study is the first to show that prolonged breastfeeding could increase intelligence until the age of 30 years. Adding to that, it also has an impact both at an individual and societal level, Horta added.

Horta further said that the unique thing about the study was that the people who were considered in the study were not more common among highly educated and high-income women. Horta and other researchers analyzed data from another study of children born in Pelotas in 1982.

Data on breastfeeding was then compared to IQ test results at the average age of about 30 years, as well as the educational achievement and income of 3,493 participants.

According to the researcher, “The researchers divided these subjects into five groups based on the length of time they were breastfed as infants, controlling for 10 social and biological variables that might contribute to the IQ increase including family income at different stages like birth, parental schooling and so on”.