Washington, Dec 10: A new study by researchers at the University of Texas Medical Branch at Galveston has found yet another reason why women should breast-feed their babies, for it helps infants overcome a genetic tendency toward ear infections.

About 19 percent of children are prone to chronic and recurrent ear infections, known to physicians as "otitis media", which can interfere with language development and lead to learning difficulties.

As a part of the research the boffins examined genetic samples taken from 505 children in Texas and Kentucky, about 60 percent of whom were classified as "otitis media susceptible" because they had suffered an ear infection before the age of 6 months; had undergone three or more episodes of acute otitis media within a six-month period; had four or more episodes within a 12-month period; or had six or more episodes by age 6.

Children who had required drainage tubes to assuage recurrent or persistent ear infections were also placed in the "susceptible" category.

Lead author Janak A. Patel, a professor in the infectious disease division of UTMB's Department of Pediatrics, said that the team had been on the look out for small variations in three important genes that produce inflammatory signalling molecules for the immune system, and through their research had found two such variations.

"We know that the tendency to get this infection runs in families, and so we decided to look for small variations — what we call ‘single-nucleotide polymorphisms,' or SNPs — in three important genes that produce inflammatory signalling molecules for the immune system. Two of them stood out on their own as signals of increased risk," he said.

The two identified genes generate the immune proteins known as tumour necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6).

The researchers found that SNPs in each individual gene were enough to create increased risk for childhood ear infections, and simultaneous SNPs in both genes created even more risk.

They now believe that the particular variations detected cause greater production of inflammatory signalling molecules and reduce immune system effectiveness.

They also found that the effect could be counteracted with a practice long known to increase immune resistance: breast-feeding.

The boffins also found that breast-feeding also kept kids protected from recurrent infections even later in childhood.

"This is a major finding, that breast-feeding neutralized the effect even in kids who had all the genetic polymorphisms. Not only that, they were protected from recurrent infections even later in childhood, long after they stopped breast-feeding," Prof Patel said.

The UTMB study is published in the December issue of the journal Pediatrics. (ANI)