From Baby Breaths to Childhood Wheeze

Wheezing during childhood may be related to lung function during infancy

(RxWiki News) Babies with smaller lung capacity could have breathing problems later, especially if they take up smoking as teenagers.

A new study suggests that infants with lower lung function might have a higher risk for developing a wheeze or asthma by the age of 18.

"Consult a pediatrician if your child has trouble breathing."

David Mullane, MD, of University College Cork, Ireland, and colleagues led the study to find out if there was a relationship between a baby’s lung function in infancy and their chances of developing a wheeze beyond childhood.

In order to carry out the study, the researchers followed 150 children from the age of one month to 18 years old.  

At one month of age, the infants had their lung function tested to see how much air they could breathe into their lungs and how easily it flowed in and out of their lungs. The babies also got skin prick tests to see if they had any allergies to cows milk, egg white, rye grass and dust mites.

The children were then followed up with at ages 6, 12 and 18 years old. At these follow-up visits they were asked if they had experienced any wheezing in the past year. They were also asked if they had been diagnosed with asthma.

The researchers also repeated the allergy skin prick test, adding tests for mixed grass, a different kind of dust mite, cat dander, dog dander and different types of mold and fungus.

At the follow-up done at age 18, their lung function was tested again. The 18-year-olds were also asked if they currently smoked cigarettes.

The researchers found that by 18 years of age, 37 children - 25 percent – had a recent wheeze, meaning they had wheezed within the past year. Only 20, or 13 percent, had been diagnosed with asthma.   

The participants were put into four categories according to how frequently, and when, their wheezing occurred. A total of 13 participants had persistent wheeze and 19 had later-onset wheeze.

Fifteen of the participants reported that their wheeze had gotten better temporarily and 96 of the children reported no history of wheezing.

The children with a persistent wheeze had 43 percent less lung function than the children without a wheeze. They also had around a 7.1 times higher chance of having allergic reactions as babies compared to the non-wheezing children.

Compared with the no-wheeze group, children with persistent wheezing were 6.8 times more likely to have an asthmatic mother and almost five times more likely to be active smokers.  

Children that had been diagnosed with asthma at ages 6, 12 and 18 years were 6.6 times more likely to have a mother with asthma than children without asthma. They were also 10.4 times more likely to have tested positive for allergies when they were infants.

The data also suggested that each 1 percent increase in lung function at the age of one month was associated with an average of 1 percent reduced risk of wheeze later in childhood.

The same was true for developing asthma by age 18. For each 1 percent increase in lung function at age one month there was an associated 1 percent reduced risk for asthma at age 18.

The researchers found that reduced lung function at one month of age was associated with an increased risk of wheezing only for the 18-year-olds who were current smokers.

"These results suggest that reduced early airway function and later exposures such as smoking are important to the cause of obstructive respiratory diseases in young adults,” the authors wrote.

"To our knowledge, this study is the first to report an association between reduced lung function in infancy and wheeze beyond childhood," they wrote.

The authors also noted that since the number of children in the study was so small, it’s important that new research is conducted to confirm their results.

“Interventions aimed at preventing young children with asthma symptoms and reduced lung function from smoking might prevent persisting symptoms of obstructive airways disease," they concluded. 

The study was published February 18 in the journal JAMA Pediatrics.

The research was funded by the National Medical and Health Research Council of Australia. The authors reported no potential conflicts of interest.

Review Date: 
February 21, 2013