Chest
Clinical InvestigationsAirwaysDifferential Cell Counts in Sputum in Respiratory Epidemiology: A Pilot Study
Section snippets
Materials and Methods
In a recent cross-sectional epidemiologic study conducted by questionnaire as part of the European Community Respiratory Health Study (ECRHS),4 we recruited > 3,000 adults aged 20 to 44 years from the city of Hamilton, Ontario, using random-digit dialing to obtain a representative sampling. From this cohort, a sample of 503 subjects attended the laboratory for more detailed questionnaires and investigations, as part of the ECRHS study design. We reviewed these 503 subjects to select subjects
Results
Of 149 subjects recruited, 107 subjects (71.8%) produced sputum suitable for analysis. We did not observe any adverse event during sputum inductions. Characteristics of the 107 subjects who completed the study are shown in Table 1. Approximately one third of subjects reporting asthma received inhaled corticosteroids.
There was no difference in mean FEV1 and FEV1 percent predicted among the four subgroups, but there was greater airway responsiveness (expressed as BR index) among subjects
Discussion
The purpose of this study was to determine the usefulness of differential cell counts in induced sputum as an epidemiologic tool to discriminate asthma from other causes of respiratory symptoms reported in population studies. We have previously shown an increase in sputum eosinophils to a median of 4.5% in subjects presenting with uncontrolled asthma and airway hyperresponsiveness with PC20 of < 4 mg/mL.2 However, in a community setting, sputum examination did not differentiate subjects with
References (19)
- et al.
Bronchial responsiveness to histamine or methacholine in asthma: measurement and clinical significance
J Allergy Clin Immunol
(1981) - et al.
Relationships of bronchial responsiveness assessed by methacholine to serum IgE, lung function, symptoms, and diagnoses in 11-year-old New Zealand children
J Allergy Clin Immunol
(1992) - et al.
Measuring airway inflammation in asthma: eosinophils and eosinophilic cationic protein in induced sputum compared with peripheral blood
J Allergy Clin Immunol
(1997) - et al.
Chronic cough: eosinophilic bronchitis without asthma
Lancet
(1989) - et al.
Asthma, asthma-like symptoms, chronic bronchitis, and the degree of bronchial hyperresponsiveness in epidemiologic surveys
Am Rev Respir Dis
(1987) - et al.
Indices of airway inflammation in induced sputum: reproducibility and validity of cell and fluid-phase measurements
Am J Respir Crit Care Med
(1996) - et al.
Sputum in severe exacerbations of asthma: kinetics of inflammatory indices after prednisone treatment
Am J Respir Crit Care Med
(1997) - et al.
Variations in the prevalence of respiratory symptoms, self-reported asthma attacks, and use of asthma medication in the European Community Respiratory Health Survey (ECRHS)
Eur Respir J
(1996) Standardization of spirometry: 1994 update
Am J Respir Crit Care Med
(1995)
Cited by (13)
The relationship between inflammation and symptoms in asthma
2008, Revue des Maladies RespiratoiresSputum tests in the diagnosis and monitoring of asthma
2004, Annals of Allergy, Asthma and ImmunologyHow should we quantify asthma control? A proposal
2002, ChestCitation Excerpt :Furthermore, in regard to measures of airway inflammation, it can be assessed by various methods. We chose the quantification of eosinophils in induced sputum, as this method is increasingly used and its variability had been studied in the normal and asthmatic populations.25 Airway inflammation could be assessed by other methods such as exhaled nitric oxide or other types of noninvasive measurements.26
Tackling asthma phenotypes in community studies
2009, ThoraxUnderdiagnosis and overdiagnosis of asthma
2018, American Journal of Respiratory and Critical Care MedicineAddressing the misdiagnosis of asthma in adults: where does it go wrong?
2016, Expert Review of Respiratory Medicine
Support was provide by a grant from the Father Sean O'Sullivan Research Centre, St. Joseph's Hospital, Hamilton.
Dr. Lemière was the recipient of a fellowship from Merck Canada.