In a randomized, double-blind, placebo-controlled study in children with asthma, ages 6 to 18, Dutch researchers found that influenza vaccination did not significantly reduce the number, severity, or duration of asthma exacerbations caused by the flu. The investigators studied 349 children who received placebo vaccinations and 347 who were given inactivated influenza vaccine. They revealed that 42 pharyngeal swabs from the children were positive for influenza, with 24 in the vaccine group and 18 in the placebo group--a 33 percent difference. The authors said that the influenza-related asthma exacerbations they detected were all of similar severity. They study's young participants were recruited through family physicians in the city of Rotterdam and its surrounding areas during the flu seasons of 1999 to 2000 and 2000 to 2001. The children in the study were only involved for one flu season. Starting the day after his or her vaccination, each child was asked to fill in a daily diary. In their booklet, they scored upper and lower respiratory tract symptoms, use of medication, physician visits, and trips to other medical facilities. When the symptom score reached a predefined level, the investigators would take a pharyngeal swab. The primary outcome of the study was the number of asthma exacerbations associated with proven influenza viruses. They study appears in the second issue for February 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
Maternal and personal smoking synergize to increase airflow limitation in offspring
Mothers who have smoked adversely affect their offspring's lung function, as they grow older, in at least three major ways. The researchers concluded that maternal smoking: lowers lung function whether the offspring personally smoke or not; was associated with greater smoking intensity in their children and less ability to quit by those who have taken up smoking; and that maternal smoking behavior appeared to synergize with their offspring's personal smoking to increase airflow limitation and the likelihood of developing Chronic Obstruction Pulmonary Disease (COPD). British researchers looked at 2,000 adult offspring, ages 30 to 59, from 1,477 families who had participated in a 1972 to 1976 population study on smoking. There were 884 male and 1,116 female offspring involved in the study. In the group, there were 949 never smokers, 552 former smokers, and 499 current smokers. The authors were trying to determine whether maternal and personal smoking synergized to increase airflow limitation in the offspring. For their analysis, the duration and intensity of personal smoking was set at 25 years and 20 cigarettes per day. The effect of 10 cigarettes per day maternal smoking on airflow limitation was numerically equivalent to 10 years of personal smoking. The investigators pointed out that in ever smokers, the risk of prevalent COPD increased 1.7 per 10 cigarettes per day maternal smoking. The study appears in the second issue for February 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
New diagnostic test for asthma
After evaluating a "gold standard" set of tests recommended by international guidelines to confirm a diagnosis of asthma, researchers from New Zealand showed that a simple measurement of exhaled nitric oxide in patients was clearly superior to currently used objective methods to diagnose the disease. A test called induced sputum analysis also gave superior results but was deemed much more technically demanding, and not routinely available. The investigators studied 47 patients with symptoms suggestive of asthma, using a comprehensive, fixed-sequence of standard diagnostic tests. (Bronchial asthma has a prevalence of about 20 percent in young adults in Western populations, according to the authors.) The researchers checked the sensitivities and specificities for peak flow measurements, spirometry, and changes in certain airway parameters after a trial use of steroid. These results were compared with exhaled nitric oxide measurements and sputum cell counts. The authors said that the sensitivities for each of conventional tests ran from 0 to 47 percent. These results were considerably lower than for exhaled nitric oxide measurements that ran 88 percent, along with 86 percent for sputum eosinophil analysis. (Exhaled nitric oxide increases in patients with bronchial asthma.) Overall, the diagnostic accuracy of the exhaled nitric oxide and sputum analysis was significantly greater. The investigators noted that it is much more logical to use exhaled nitric oxide as a surrogate test for airway inflammation than to rely on physiological changes for which the measurements are variable over time, are often undetectable in mild cases, and correlate poorly with clinical symptoms. The study appears in the second issue for February 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine