Children who become sensitive to allergens, such as cat hair, and suffer from wheezing in their first 3 years of life are prone to developing asthma, according to an article in the August 26 issue of The Lancet.

Between birth and school age, some children who experience persistent wheezing lose their lung function and develop asthma; but others do not. The factors that determine which children develop asthma have been unclear until now.

In the study Sabina Illi, PhD, from the University Children’s Hospital, München, Germany, and colleagues investigated the role of allergen exposure in early life and sensitisation to allergens on the development of lung function and asthma. The investigators enrolled more than 1,300 children, born in 1990, into the study. Approximately 500 of the children were found to have known risk factors for allergen sensitivity at birth. These risk factors are high level of immunoglobulin E (IgE) antibodies in umbilical cord blood and/or at least two first-degree relatives with allergen sensitivity.

From birth to age 13 the researchers interviewed parents about their children’s asthma and measured levels of IgE antibodies in the children. They found that 90% of children who experienced repeated wheezing but were not susceptible to allergies lost their symptoms at school age and retained normal lung function at puberty. However, the children who had repeated wheezing and developed sensitivity to allergens in their first 3 years of life were more likely to develop a loss of lung function and asthma. The researchers also found that exposure to high levels of allergens contributed to development of asthma.