Feeding breast milk compared with formula may also reduce the risk of diarrhoea, according to researchers from Research Institute at Nationwide Children's Hospital in the US.
A total of 491 mothers completed surveys as part of the study. Three out of four women used some combination of feeding from the breast, pumped milk and formula in the first 12 months of their children's lives, researchers said.
After accounting for demographic and other related factors, researchers found that one month of feeding at the breast was associated with a 4 per cent reduction in the odds of ear infection, and a 17 per cent reduction for infants fed at the breast for six months of infancy.
"While it is not completely clear why ear infections may be related to bottle feeding, it could be because bottles can create a negative pressure during feeding," said Sarah Keim from Nationwide Children's Hospital.
"This negative pressure is then transferred from the bottle to the middle ear of the infant during feedings, which may precipitate ear infections," said Keim.
Diarrhoea risk was reduced by 25 per cent for infants fed any breast milk for six months, and by 26 per cent for infants fed at the breast for 6 months, they said.
Infants fed formula for 6 months had a 34 per cent increased risk of experiencing diarrhoea.
According to researchers, this finding suggests that the substance fed, rather than the mode of feeding, may underlie differences in risk of diarrhoea.
"This research begins to identify unique and separate associations of substance fed and mode of breast milk delivery, and demonstrates the importance of exploring these distinctive exposures in infant feeding research," said Kelly McNamara Boone from Nationwide Children's Hospital.
The findings were published in the Journal of Pediatrics.
