50 Years On: Severe Childhood Asthma Persists in Middle Age

Neil Osterweil

June 12, 2014

Children with severe asthma are significantly more likely to have reduced lung function midway through life's journey than their peers with only mild wheeze, according to the results of a 50-year prospective study.

Severe asthma in childhood was associated with a nearly 12-fold risk that a 50-year-old would have current asthma. Women and those with hay fever in childhood had a 2-fold risk of being asthmatic adults, report Andrew Tai, MBBS, FRACP, PhD, from the Department of Respiratory and Sleep Medicine, Women's and Children's Hospital, North Adelaide, South Australia, and colleagues.

"[T]he severity of asthma in childhood influences the clinical outcomes in adult life, including the likelihood of achieving clinical remission," the investigators write in an article published in the June issue of the Journal of Allergy & Clinical Immunology.

The Beatles were just beginning to make a splash on the international scene in 1963 and 1964, when the participants in the Melbourne Asthma Study were recruited. After a survey of 30,000 second graders, investigators randomly selected a group of 7-year-olds and a second group of 10-year-olds with severe wheezing.

The cohort included subgroups of children with mild wheezy bronchitis (fewer than 5 episodes), wheezy bronchitis or respiratory tract infection (5 or more episodes, now classified as intermittent asthma), asthma (wheezing not associated with respiratory tract infections), severe asthma (at least 10 attacks in the 2 years before or persistent symptoms at age 10 years and barrel-chest deformity and/or reduction of the forced expiratory volume in 1 second [FEV1]–forced vital capacity [FVC] ratio to 50% or less).

Of the 484 original participants, 21 have died, including 2 from asthma, both of whom had had severe asthma. A total of 346 participants were available for follow-up at age 50 years, and of this group, 197 (57%) completed a questionnaire and lung-function tests; an additional 149 (43%) completed only the questionnaire.

The authors found that 64% of participants in the mild wheezy bronchitis/wheezy bronchitis groups had remission of asthma compared with 47% of those in the asthma group and 15% in the severe asthma group. Patients in the asthma group who experienced remission were most likely to have remissions during adolescence.

In multivariate analysis controlling for sex, atopy, and body mass index, factors that significantly predicted asthma at age 50 years include severe childhood asthma (odds ratio [OR], 11.9; 95% confidence interval [CI], 3.4 - 41.8), female sex (OR, 2.0; 95% CI, 1.1 - 3.6), and childhood hay fever (OR, 2.0; 95% CI, 1.0 - 4.0).

When the investigators looked at the decline in lung function over time, they found that reduced mean FEV1 and FEV1-FVC ratios in the childhood asthma group were established by age 7 years and, among those with severe asthma, by age 10 years. Lung function in these groups continued to track below that of controls and of participants with wheezy bronchitis over time.

"This is a fascinating paper," commented Scott Schroeder, MD, chief, Division of Pediatric Pulmonology & Allergy at the Floating Hospital for Children at Tufts Medical Center in Boston, Massachusetts.

"A 50-year study — you just don't see them anymore," he said.

Dr. Schroeder, who was not involved in the study, told Medscape Medical News that the study supports the hypothesis that airway remodeling and reduced lung function may begin in childhood.

"There's a lot of controversy into whether remodeling does occur, or scarring, and I think that it actually does, and this [article] sort of points to that, because the lung function doesn't change when they become adults, which shows that there is probably something going on very early, and the ones who are most severe are going to be severe all their lives, unfortunately," he said.

"It gives me more ammunition to say to primary care docs or anyone who is taking care of people with severe asthma, you've got to start treating them very, very early on," Dr. Schroeder added.

The study was funded by the National Medical Health Research Council, Australia. The authors and Dr. Schroeder have disclosed no relevant financial relationships.

J Allergy Clin Immunol. 2014;133:1572-1578. Abstract


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