Recurrent wheezing in infants should not be ignored. Here is more evidence that signs of asthma may be present in even very young children and infants. SS
Lung Function Deficits in Babies May Lead to Future Asthma
March 30, 2012 — In the future, scientists may want to explore ways to prevent childhood asthma long before it fully evidences itself, by focusing on neonates and young babies.
New research suggests that lung function deficits related to future asthma may develop before birth, in infanthood, and in early childhood, suggesting that asthma research could target prevention at these times.
Hans Bisgaard, MD, head of the Danish Pediatric Asthma Centre in Copenhagen, Denmark, and colleagues presented the results of their study in an article published online March 29 in the American Journal of Respiratory and Critical Care Medicine. The authors found that children who develop asthma by age 7 years have respiratory problems as infants, including increased bronchial responsiveness and deficits in lung function.
"It seems that lung function changes associated with asthma occur very early in life and maybe even before birth," Dr. Bisgaard, who is also a professor of pediatrics at the University of Copenhagen, said in a news release. "This may explain the lack of effect from early intervention with inhaled corticosteroids and should direct research into the pathogenesis and prevention of asthma towards the earliest phases of life."
The authors of the study, which is the most comprehensive prospective study yet of the association between early childhood asthma and lung function from birth to school age, note that it is unclear which comes first: the development of asthma or the development of deficits in lung function.
"These questions are important for the direction of research into the origins and prevention of asthma," they write. "[S]hould we expect genetic or prenatal programming of the disease; or is there an early window of opportunity to prevent airway remodeling during early symptoms?"
In the study, the researchers analyzed the interaction between asthma and lung function growth from neonatal age to age 7 years in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), a prospective clinical study of a birth cohort of 411 children.
"Previous research on the relationship between neonatal lung function and the development of asthma has been conflicting," Dr. Bisgaard said in the news release. "Our study shows that children with asthma by age seven already had significant airflow deficits and increased bronchial responsiveness as neonates. Lung function deficits also progressed throughout childhood in our study, suggesting a potential opportunity for early intervention."
The newborns were enrolled in the first month of life and were assessed at 6-month intervals. Additional visits were arranged when there was an onset of respiratory symptoms.
The diagnosis of asthma was based on daily diary cards and health visits every 6 months during the first 7 years of life.
The researchers analyzed the interaction between asthma and lung function growth from neonatal age to age 7 years by measuring neonatal spirometry and bronchial responsiveness to methacholine through forced flow-volume measurements. They also measured lung function through spirometry when the child turned 7 years old, using a pneumotachograph, which records the rate of airflow to and from the lungs.
The results showed that children with asthma at age 7 years had experienced a significant airflow deficit as newborns (forced expiratory flow rate [FEF]50 reduced by 0.34 Z score by 1 month; P < .03). This deficit worsened significantly through early childhood (FEF50 reduced by 0.82 Z score by age 7 years; P < .0001).
"We found that approximately 40% of the airflow deficit that was associated with asthma in our study was present at birth, while 60% developed through early childhood along with the disease," Dr. Bisgaard said in the news release. "This indicates that both prenatal and early childhood mechanisms are potential intervention targets for the prevention of asthma."
Further results showed that bronchial responsiveness to methacholine, which leads to narrowing of the airways, was also significantly related to the development of asthma. Reactivity of the neonatal airway was a stronger predictor of asthma than neonatal lung function, the research showed.
"This airflow deficit progressed in the first 7 years of life suggesting that disease mechanisms are operating both before and after birth," the authors write.
One limitation is that the study used a homogenous study sample, which might limit the generalizability of results to other populations, according to written materials from the American Thoracic Society.
The Lundbeck Foundation, the Pharmacy Foundation of 1991, the Augustinus Foundation, the Danish Medical Research Council, and the Danish Pediatric Asthma Centre provided the core support for the study. The authors have disclosed no relevant financial relationships.
Am J Respir Crit Care Med. Published online March 29, 2012. Abstract
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