NIGHT COUGH IN A POPULATION-BASED SAMPLE OF CHILDREN - CHARACTERISTICS, RELATION TO SYMPTOMS AND ASSOCIATIONS WITH MEASURES OF ASTHMA SEVERITY

Nocturnal cough in asthma is a common but poorly understood phenomenon , The aims of this study were to determine the relationship between re corded night cough, reported night cough and current wheeze in a popul ation-based sample of children previously identified as wheezy, and to examine the relationship of nocturnal cough to current symptoms, mark ers of asthma severity and environmental exposure. Children were reass essed in the early school years by measuring current symptoms, ventila tory function, bronchial reactivity, peak flow variability, respirator y symptom diaries and home monitoring of overnight cough, transcutaneo us arterial oxygen saturation, room temperature and humidity, Night st udies were performed on 59 asymptomatic children and 41 children with current wheeze. Cough occurred more frequently in current wheezers com pared to asymptomatic children (16 out of 41 (39%) vs 11 out of 59 (19 %)), and more cough episodes were recorded (median 3.5 vs 2.0), Night cough was not associated with bronchial reactivity, peak flow variabil ity, degree of morning dip, mean overnight arterial oxygen saturation, ventilatory function, maternal smoking or treatment of asthma, Howeve r, it was associated with lower overnight air temperature. Although ni ght cough is more common in current wheezers, there is poor agreement between recorded and reported night cough, Objective tests of asthma s everity are of little use in predicting its presence in this age group , The sleeping environment deserves further study.