A Case‐Control Study of the Role of Cold Symptoms and other Historical Triggering Factors in Asthma Exacerbations

Abstract

BACKGROUND: Asthma exacerbations can be provoked by many triggers such as allergens, respiratory irritants and viral infections. The relative importance of these has not been prospectively documented in a case-control study. OBJECTIVE: To assess the relative importance of colds and other nonclimatic historical triggers of asthma exacerbations. METHODS: One hundred and nineteen adults and children with asthma in two Canadian cities participated in a one-year study of the role of exacerbating factors in asthma. Among these, 36 pairs (21 adult, 15 children) completed the casecontrol study. Patients were considered cases if they developed an acute asthma exacerbation and notified the centre within 24 h to allow the completion of a questionnaire and viral studies (cultures of nasopharyngeal swabs and serology). Control people with asthma were matched for sex, age and area of residence, had no exacerbation during the preceding four weeks and participated within 48 h of the case patients.

Rhinoviruses significantly affect day-to-day respiratory symptoms of children with asthma

“…This raises the issue of other factors that might be responsible for day-to-day variation in asthma and respiratory symptoms. Much of our understanding of this subject is derived from studies of acute exposure episodes, 49 patients' perceptions about triggers, 50 and studies of uncommon events within large community studies. 51 Recent reviews 52-54 cite multiple types of inhaled exposures, medication adherence, and emotional, dietary, and hormonal factors as risk factors for exacerbations, but population attributable risks for day-to-day asthma and respiratory symptoms have not been reported.…”

Risk factors precipitating exacerbations in adult asthma patients presenting at Kalafong Hospital, Pretoria

“…In accordance with a Canadian study, 24 our controls were chronic asthmatics with no exacerbations during the preceding four weeks, selected from the asthma clinics at Kalafong Hospital. Controls were selected longitudinally throughout the course of the study (density sampling).…”

Environmental tobacco smoke and health in the elderly

“…In community-and hospital-based surveys, 69-78% of asthma patients report that cigarette smoke aggravates their asthmatic symptoms [134][135][136]. Six epidemiological studies [91,[137][138][139][140][141] have addressed the effects of ETS on pre-existing asthma in adults, but only one of these included subjects aged w60 yrs [137].…”