ASSESSING THE RISKS OF ENVIRONMENTAL TOBACCO SMOKE

Exposure to environmental tobacco smoke increases the risk for lung cancer and other respiratory diseases, according to Paulo Vineis, of Imperial College London, and colleagues. Their study also found that frequent exposure to environmental tobacco smoke during childhood is associated with an increased risk of developing lung cancer in adulthood. Although this observation is not new, this is the first prospective study to report such an association, the authors said. Results of their study were published in the February 5 BMJ.

The study involved 303,020 people who had never smoked or who had stopped smoking for at least 10 years before enrolling in the study. Information on exposure to environmental tobacco smoke was available for 123,479 of these participants. Over seven years of follow-up, 97 of these individuals were newly diagnosed with lung cancer, 20 were diagnosed with upper respiratory cancers, and 20 had died from COPD or emphysema.

Results indicated that former smokers were 1.5 to 2.0 times more likely to have a respiratory disease than those who had never smoked. This elevated risk was limited to exposure related to work. These findings suggest that “former smokers might be more susceptible to the effects of environmental tobacco smoke” than those who have never smoked.

The investigators also found that “environmental tobacco smoke exposure during childhood showed an association with lung cancer, particularly among those who had never smoked; the association was significant for daily exposure for many hours.” Patients exposed to environmental tobacco smoke during childhood were 3.63 times more likely to develop lung cancer.

They also observed that cotinine concentrations, measured in 1,527 patients, were associated with self-reported exposure to environmental tobacco smoke; however, cotinine concentrations were not associated with risk of lung cancer or other diseases, the investigators added.

Professor Vineis’ research team concluded that environmental tobacco smoke is a risk factor for lung cancer and other respiratory diseases, particularly in former smokers. Their study reinforces “the conclusions of the IARC Monograph Working Group that there is sufficient evidence of the carcinogenicity of environmental tobacco smoke in humans.”

Vineis P, Airoldi L, Veglia F, et al. Environmental tobacco smoke and risk of respiratory cancer and chronic obstructive pulmonary disease in former smokers and never smokers in the EPIC prospective study. BMJ. 2005;330:227-231.

RESPONSES TO TWO ASTHMA TREATMENTS VARY AMONG CHILDREN

Researchers have identified specific asthma characteristics in children that could help determine the type of asthma treatment they will best respond to, according to a study in the February Journal of Allergy and Clinical Immunology. Stanley J. Szefler, MD, and colleagues “examined the variability in response to inhaled corticosteroids and leukotriene receptor antagonists … to identify patient features that would serve as indicators for selection of the medication most likely to achieve a favorable response in individual patients.”

A total of 144 children ages 6 to 17 with mild to moderate persistent asthma were randomly assigned to one of two crossover treatment sequences. Patients received either fluticasone propionate (100 μg twice daily) or montelukast (one tablet at night, 5 mg for patients ages 6 to 14 and 10 mg for those ages 15 to 18) for eight weeks each. According to the researchers, “during the active treatment period for one drug, the participant received a placebo for the alternative drug.” Researchers measured the percentage change in prebronchodilator FEV₁ from baseline to the end of each treatment period.

Of the 144 patients, 216 completed treatment with both fluticasone and montelukast. Seventeen patients did not complete the study, and 12 experienced treatment failure due to asthma exacerbations. Dr. Szefler and colleagues found that treatment with fluticasone resulted in a 5% to 10% improvement in FEV₁ in 29% of patients and a 10% or greater improvement in FEV₁ in 30% of patients. Treatment with montelukast, however, resulted in a 5% to 10% improvement in FEV₁ in 17% of patients and a 10% or greater improvement in FEV₁ in 16% of patients. When response was defined as an improvement of 7.5% in FEV₁, 17% of patients responded to both treatments, 23% responded to fluticasone alone, 5% responded to montelukast alone, and 55% responded to neither treatment.

The researchers found that patients who did not respond to either medication had higher baseline pulmonary function and lower levels of markers of allergic inflammation. They said, “This group might represent a specific asthma phenotype with unaltered pulmonary function and no evidence of allergic airway inflammation but with frequent symptom days.” Further investigation involving this subgroup is warranted, they said.

The researchers noted that the findings of this study could help “clinicians in the choice of asthma control medication.” They recommended that children with reduced pulmonary function or elevated levels of markers indicating allergic inflammation be treated with inhaled corticosteroids. Those without elevated signs of allergic inflammation could receive a therapeutic trial of either medication with an assessment of response.

Dr. Szefler and his colleagues suggested that “asthma therapy might soon move from the current approach based on mean responses in populations to one in which the treatment that is most likely to expeditiously achieve a favorable response is identified for each individual patient on the basis of her or his phenotypic and possibly genotypic characteristics.”

Szefler SJ, Phillips BR, Martinez FD, et al. Characterization of within-subject responses to fluticasone and montelukast in childhood asthma. J Allergy Clin Immunol. 2005;115:233-242.

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