Rationale: The effect of early life wheezing on respiratory function and continued symptoms through adolescence has not been fully described. Using data from a population-based birth cohort in Tucson, Arizona, we previously described four phenotypes based on the occurrence of wheezing lower respiratory illnesses before age 3 yr and active wheeze at age 6 yr: never wheezers (n ϭ 425), transient early wheezers (n ϭ 164), persistent wheezers (n ϭ 113), and lateonset wheezers (n ϭ 124). Objective: We sought to determine the prognosis for these phenotypes, with reference to lung function and symptoms, through adolescence. Methods: Current wheeze was assessed by questionnaire, lung function was measured by conventional spirometry, and atopy was determined by skin prick tests. Results: The prevalence of atopy and wheeze by age 16 yr was similar for never and transient wheezers and for persistent and late-onset wheezers. Both transient early, and persistent wheezers had significantly lower FEF 25-75 (-259 ml/s, p Ͻ 0.001, and -260 ml/s, p ϭ 0.001, respectively), FEV 1 (-75 ml, p ϭ 0.02, and -87 ml, p ϭ 0.03, respectively), and FEV 1 :FVC ratio (-1.9%, p ϭ 0.002, and -2.5%, p ϭ 0.001, respectively) through age 16 yr compared with never wheezers. Late-onset wheezers had levels of lung function similar to those of never wheezers through age 16 yr. There was no significant change in lung function among subjects with any of the four phenotypes, relative to their peers, from age 6 to 16 yr. Conclusion: Patterns of wheezing prevalence and levels of lung function are established by age 6 yr and do not appear to change significantly by age 16 yr in children who start having asthmalike symptoms during the preschool years.
Background-Together with smoking, the level of lung function attained in early adulthood is among the strongest predictors of chronic obstructive pulmonary disease. Whether airway function measured shortly after birth is a determinant of this level is currently unknown.
Background It is increasingly evident that microbial colonization of the respiratory tract might have a role in the pathogenesis of asthma. Objective We sought to characterize and compare the microbiome of induced sputum in asthmatic and nonasthmatic adults. Methods Induced sputum samples were obtained from 10 nonasthmatic subjects and 10 patients with mild active asthma (8/10 were not using inhaled corticosteroids). Total DNA was extracted from sputum supernatants and amplified by using primers specific for the V6 hypervariable region of bacterial 16s rRNA. Samples were barcoded, and equimolar concentrations of 20 samples were pooled and sequenced with the 454 GS FLX sequencer. Sequences were assigned to bacterial taxa by comparing them with 16s rRNA sequences in the Ribosomal Database Project. Results All sputum samples contained 5 major bacterial phyla: Firmicutes, Proteobacteria, Actinobacteria, Fusobacterium, and Bacteroidetes, with the first 3 phyla accounting for more than 90% of the total sequences. Proteobacteria were present in higher proportions in asthmatic patients (37% vs 15%, P < .001). In contrast, Firmicutes (47% vs 63%, P = .17) and Actinobacteria (10% vs 14%, P = .36) were found more frequently in samples from nonasthmatic subjects, although this was not statistically significant. Hierarchical clustering produced 2 significant clusters: one contained primarily asthmatic samples and the second contained primarily nonasthmatic samples. In addition, samples from asthmatic patients had greater bacterial diversity compared with samples from nonasthmatic subjects. Conclusion Patients with mild asthma have an altered microbial composition in the respiratory tract that is similar to that observed in patients with more severe asthma.
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