Life in General

CHICAGO (Reuters) - Children who received antibiotics as babies have a higher risk of developing asthma by age 7, Canadian researchers said on Monday.

Antibiotics are commonly prescribed to children under age 1 for a host of reasons, most often for lower respiratory tract infections such as bronchitis and pneumonia or upper respiratory tract infections like ear and sinus infections.

Anita Kozyrskyj and colleagues at the University of Manitoba in Winnipeg and McGill University in Montreal studied antibiotic use in 13,116 children from birth to age 7.

Respiratory symptoms early on can be a sign of future asthma. To control for that, they sorted out infants who got antibiotics for non-respiratory tract infections, such as impetigo or urinary infections.

Of those, the risk for asthma before age 7 doubled compared to babies who received no antibiotics before age 1, according to the study, which appeared in the journal CHEST.

The researchers found that babies who were exposed early to antibiotics and who did not have a dog in the home before their first birthday were also at higher risk for asthma by age 7.

They said the presence of a dog likely increases the infant's exposure to germs, which can help kick-start the baby's immune system.

Asthma is an inflammation of the airways that makes breathing difficult. Symptoms can include wheezing, shortness or breath, coughing and chest tightness.