Key Point:

Intervention programs during the first year of life may be effective in preventing asthma in young children.

WINNIPEG, MANITOBA—Asthma, like many other diseases, arises from gene-environment interactions. However, the increasing asthma prevalence in recent years is unlikely to be related to genetic changes, which suggests a stronger role for the environment in the pathogenesis of the condition. Recent evidence suggests that a multifaceted intervention program aimed at a child’s home environment during the first year of life is effective in reducing asthma rates at age 2.[1]

Allan Becker, MD, and colleagues randomized 545 infants at high risk for asthma (because of immediate family history of the disease) and their families to intervention or control groups. Interventions included decreasing exposure to indoor allergens, such as dust mites and environmental tobacco smoke; encouraging breast-feeding; and delaying the introduction of solid foods.

INTERVENTIONS HELPFUL

At age 2 years, the children were tested for asthma and atopy. Almost 20% had asthma, and 14.5% were atopic. Atopy rates were not statistically different between the intervention and control groups (15.6% and 13.7%, respectively). However, the asthma rate was significantly lower in the intervention group (16.3%) than in the control group (23.0%). This difference was mainly attributable to a reduction in the rate of persistent asthma in the intervention group (4.9% versus 11.3%, respectively).

In addition, there was a 90% decrease in the rate of recurrent wheeze at age 2 in the intervention group compared with the control group. This finding is important, said Dr. Becker, a Professor of Pediatrics and Immunology at the University of Manitoba, given that asthma is primarily a wheezing disease in young children.

The study was not designed to assess which of the interventions was most helpful in reducing the asthma rates. However, Dr. Becker believes that “each aspect is important, as is the timing of the environmental interventions.” Focusing the interventions during the first year of life may be a “window of opportunity” for influencing the immune responses associated with asthma, he explained.

The researchers found no relationship between asthma at age 2 and house dust mite or cat allergen exposure. Nor could a positive or negative correlation between breast-feeding and asthma be seen. As expected, maternal smoking during pregnancy and the first 12 months of the child’s life was associated with an increased risk of asthma at age 2. Atopy at 12 months—particularly to food—was also predictive of asthma at age 2.

Overall, Dr. Becker and his colleagues believe that their multifaceted intervention was effective in reducing asthma rates in 2-year-old children. They are continuing to follow these children to examine whether the early-life interventions will have any effect on disease occurrence when the children reach school age.

—Tamara Gibb