Asthma Watch

Published Online: Friday, March 18, 2011

Moderate-Dose ICSs May Not Provide Additional Benefit in Children
Moderate doses of inhaled corticosteroids (ICSs) may not have any added benefit in children with mild to moderate persistent asthma compared with low doses, according to a systematic review and meta-analysis published online December 6, 2011, in Pediatrics.

Researchers from the Maternal and Child Health Unit in Rio Grande, Brazil, reviewed 14 randomized controlled trials that enrolled a total of 5768 children with asthma who received 1 of 5 different ICSs. Although moderate doses were slightly more effective than low doses in improving forced expiratory volume in 1 second (FEV1) among children with mild to moderate asthma, this difference was not statistically significant (standardized mean difference, 0.11; 95% confidence interval, 0.01-0.21), suggesting that there may be no clinical advantage to increasing the dosage of ICSs.

The study, like all meta-analyses, was limited in its lack of uniformity between the included trials, including different efficacy end points, modes of data collection, and adverse event reporting. Nevertheless, the study does prove reevaluation is needed when dosing ICSs in children with mild or moderately persistent asthma, and the potential adverse events of corticosteroids, like adrenal suppression, linear growth retardation, and effects on bone mass, must be matched with potential benefit.

Wheezing with Rhinovirus Infection Linked to Asthma
Children 3 years and younger with rhinovirus respiratory infection are more likely to develop asthma later in childhood, according to a trial presented by researchers from the University of Wisconsin at the World Allergy Organization International Scientific Conference in December.

The trial, called the Childhood Origins of Asthma trial, or COAST, enrolled 285 children at high risk for developing respiratory infections. These children were followed for 6 years, during which time frequent nasal washes were collected and wheezing was assessed at different milestones. Risk factors were found and odds ratios (ORs) were calculated related to persistent wheezing.

Risks that were identified at 3 years of age included passive smoke during the first year (OR = 0.21), presence of older siblings (OR = 2.5), allergic sensitization to food protein at 1 year (OR = 2), any moderate to severe respiratory illness without wheezing during infancy (OR = 3.6), and at least 1 wheezing illness during infancy with respiratory syncytial virus (OR = 3). The most notable risk factor, however, was rhinovirus infection. Children who wheezed with rhinovirus infection at 1 year of age had a much higher risk of persistent wheezing by 3 years of age (OR = 6.6, P = 0.0001).

The researchers also concluded that viral load was related to asthma, and children in this study who later developed asthma had a much higher respiratory pathogen burden than patients who did not develop asthma. A reproduction of other studies that have shown rhinovirus infection to be a culprit in asthma, the findings shed light on a potential target to prevent asthma later in life. A vaccine against rhinovirus, although difficult to produce, may be able to prevent asthma from developing. PT

Proximity to Traffic Related to Asthma Risk
Living near a busy roadway increases a person’s risk of developing allergies and asthma, according to a study published online in the Journal of Allergy and Clinical Immunology on January 18, 2011. The study is believed to be the first based on more robust scientific data rather than solely on self-reports of asthma symptoms.

Researchers from Johns Hopkins University enrolled 725 teenagers aged 12 through 15 years who resided in shantytowns near Lima, Peru, a city whose outskirts are known to have very busy, congested roadways. These teenagers were followed for 1 year, and home visits to measure lung function and environmental air pollutants were conducted. The study found that the closer one was to the main roadways, the higher his or her risk of having asthma or allergies. The risk was 7% higher for every city block closer someone lived to the main roadway.

The researchers now plan to study genetic profiles of those at greater risk of asthma and atopy, hopefully to identify other key environmental stimuli that help trigger allergic disease.



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