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Background: The cause of rising asthma incidence over time remains unexplained. Examining trends in the age of diagnosis across successive birth cohorts may offer insights into asthma etiology., Objective: To examine trends in the age at asthma diagnosis and the age and proportion of children hospitalized at first asthma diagnosis in Ontario, Canada., Methods: Eight consecutive birth cohorts of children (1993-2000) were observed using administrative data from a universal health insurance plan in Ontario, Canada (population 13 million). Trends in the need for hospitalization and age at asthma diagnosis were examined with descriptive and survival analyses., Results: The records of 1,059,511 children were examined, of whom 201,958 developed asthma in the first 8 years of life, with an average cumulative incidence of 19.1%. Mean age at asthma diagnosis decreased from 4.7 ± 1.5 years in birth year 1993 to 2.6 ± 2.0 years in birth year 2000 (P < .0001), with a higher adjusted risk of asthma diagnosis (hazard ratio, 6.7; 95% CI, 6.5-6.9) in the first 3 years of life for children born after 1996 versus children born in the period 1993 to 1995 (hazard ratio, 1.4; 95% CI, 1.3-1.4). The proportion of children hospitalized at asthma diagnosis stayed stable while the age at first asthma hospitalization decreased over time (P < .0001)., Conclusions: This study demonstrates a significant increase in asthma incidence and a decrease in the age of asthma diagnosis across multiple birth cohorts. Changes in asthma incidence over time are primarily explained by variations in asthma rates in children younger than 3 years., (Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Screening for non-tuberculous mycobacteria (NTM) is recommended for adults with cystic fibrosis (CF). The relevance of this organism in North American pediatric CF patients is unclear as there is limited NTM prevalence data for children. We aimed to determine the prevalence of NTM in children with CF from a single expectorated sputum and identify clinical predictors of NTM isolation. Additionally, we compared two different sputum decontamination methods before mycobacterial culture., Methods: From March to November 2004, all sputum-producing patients aged 6-18 years attending the CF clinic at the Hospital for Sick Children in Toronto, Canada, were screened for NTM. Sputum samples were processed by both a single (N-acetyl-l-cysteine + NaOH) and double (N-acetyl-l-cysteine + NaOH + oxalic Acid) decontamination method. Using our CF clinic database and patient charts we analyzed differences in FEV(1), age, sex, pancreatic sufficiency, body mass index, bacterial colonization, and antibiotic use between NTM positive and negative patients., Results: Of 98 study patients, 6 (6.1%) were positive for NTM, 2 with Mycobacterium abscessus, and 4 with Mycobacterium avium complex. One patient with M. abscessus had clinically significant lung disease requiring treatment. We found no predictors of NTM isolation. The double decontamination method allowed detection of only half (3/6) of the positive NTM cultures., Conclusions: As the NTM prevalence rate in children with CF is within the range previously reported in adults and there are no reliable clinical predictors for isolation, annual sputum screening is needed to identify NTM in children. Further research is needed to determine the best sputum decontamination method for NTM culture in pediatric patients.

Objectives: To determine the proportion of pediatric patients with cystic fibrosis who do not produce expectorated sputum during routine ambulatory clinic visits and to identify clinical predictors of these patients., Design: Cross-sectional study., Setting: The cystic fibrosis clinic at The Hospital for Sick Children, Toronto, Ontario., Participants: One hundred eighty-three patients aged 6 to 18 years who attended the cystic fibrosis clinic between March 1, 2004, and November 30, 2004., Intervention: Study patients were asked to expectorate sputum for bacterial culture., Main Outcome Measures: The proportion of patients unable to produce expectorated sputum was determined. Age, sex, forced expiratory volume in 1 second, pancreatic sufficiency, body mass index, and antibiotic use were compared between patients producing sputum and those not producing sputum., Results: Eighty-three patients (45%) did not expectorate sputum. Patients not producing sputum as compared with those producing sputum were younger (mean age, 10.3 years vs 13.9 years, respectively; difference, 3.6 years; 95% confidence interval, 2.6-4.5) and had higher forced expiratory volume in 1 second (mean forced expiratory volumes in 1 second, 88% of predicted vs 72% of predicted, respectively; difference, 16%; 95% confidence interval, 10.1-22.2). Eighty-eight percent of patients not producing sputum had cough and 45% reported sputum production at home., Conclusions: Almost half of pediatric patients with cystic fibrosis aged 6 years and older do not expectorate sputum in the clinic, although nearly half of these patients do report producing sputum at home. The utility of home collection on the morning of a clinic visit and/or hypertonic saline induction should be evaluated to increase the number of useful specimens for microbiological culture.