RELATION BETWEEN RESPIRATORY SYMPTOMS, PULMONARY-FUNCTION AND PEAK FLOW VARIABILITY IN ADULTS

Background - A study was carried out to determine whether subjects with respiratory symptoms are more likely to have impaired lung function or increased airway lability, and to quantify these relationships in a population of adults. Methods - Data were collected from 511 participants (aged 20-70 years) from the Dutch part of the European Community Respiratory Health Survey (ECRHS). The symptoms analysed were: wheeze, dyspnoea greater than or equal to grade 3, nocturnal dyspnoea, cough and phlegm, and history of allergy. Lung function was measured by peak expiratory flow (PEF) and forced expiratory volume in one second (FEV(1)). PEF variability was used as an index for bronchial lability. Results - Both FEV(1) and PEF were decreased with increasing numbers of symptoms. Subjects with one symptom had an increased risk of having an FEV(1) value of <70% (OR = 4.2) and this risk increased with an increasing number of symptoms. Subjects with three or more symptoms had an increased risk of having a PEF value of <70%, a diurnal variation in PEF of >10% (both OR = 4.4), and an increased risk of high between day variation (OR = 6.6). Conclusions - Subject-reported symptoms are related to impaired lung function and to increased variability of peak flow.