20/12/2011-- A Swedish study in the journal Pediatrics found that children with a high body mass index at age 7 are at greater risk for developing asthma by age 8 and are more likely to be sensitive to inhalant allergens. Overweight children's risk of asthma did not increase if their weight was in the normal range by age 7.

Assumption about an association between obesity and asthma in children arose from epidemiologic data showing that the prevalence of both conditions has increased considerably over the past several decades. Studies of the association have generally produced supporting evidence, but the nature of the relationship has remained unclear.

Few studies examined the relationship between changes in weight (or BMI) and asthma risk in childhood. To address the issue, the authors analyzed data on Swedish children to come up with these results.

Children with a BMI in the normal range at ages 1, 4, and 7 did not have an increased risk of asthma. Additionally, children who had a normal BMI at age 7 did not have an increased risk of asthma at age 8, regardless of their BMI at ages 1 and 4.

Children who had a high BMI late in the age range of 4 to 7, or who had a persistently high BMI, had a significantly increased risk of asthma at age 8.

Source reference: Magnusson JO, et al "Early childhood overweight and asthma and allergic sensitization at 8 years of age" Pediatrics 2011.