Bronchial hyperresponsiveness to 4.5% hypertonic saline indicates a past history of asthma-like symptoms in children

To evaluate the importance of a past history of asthma-like symptoms over a period of 2 years and current bronchial hyperreactivity (BHR), 538 randoml y selected schoolchildren, initially aged 7-8 years, were examined. At year ly intervals, three standardized questionnaires, including items from the I SAAC panel, were answered by parents. Following the last questionnaire, BHR to 4.5% hypertonic saline (HS) was recorded. In survey 1, lifetime prevalence of asthma was 4.9%. During the 12-month pe riod, prevalence of wheeze and dyspnea ranged between 9.3 and 5.2% (Survey 1) and 5.9% and 4.4% (Survey 2). Among children with wheeze or dyspnea in S urvey 3, BHR (defined as a fall of baseline FEV(1)greater than or equal to 15%) was significantly more frequent (50.0% and 60.7%, respectively) than a mong children without these symptoms (12.8%, P < 0.001, and 12.8%, P < 0.00 1, respectively). The negative predictive value of BHR to have neither whee ze nor dyspnea was about 88% and did not vary throughout the study (Survey 1, 87%; Survey 2, 88%: Survey 3, 88%). The relative risk of showing BHR was significantly increased in children with wheeze (survey 2, odds ratio (OR) 3.0 (95% confidence interval (CI) 1.0-8.7)) or dyspnea (Survey 1: OR 5.9 ( 95% CI 1.9-18.5), Survey 3: 5.2(1.7-16.2), but not in children with dry cou gh or nocturnal cough (data not shown). Wheeze and dyspnea occurred repeate dly in the same individuals with BHR in a high percentage of children (83.3 % and 76.5%, respectively). In conclusion, there is a strong association between recent and previous dy spnea and current BHR, and it indicates intraindividual persistence of symp tom history. (C) 2001 Wiley-Liss Inc.