Abstract
To accurately assess putative risk factors for bronchial hyperresponsiveness (BHR), we have used multivariate models to analyse data from 4,366 children living in four regions and from 878 adults. A standard protocol was used to measure bronchial responsiveness to histamine. The prevalence of BHR was high at 7-9 yrs (16-18%), decreased significantly at 11-14 yrs (7-8%), and then increased in adults (12-14%). Atopy was the most important risk factor for BHR at all ages. In children, parental asthma, early respiratory illness and being born in Australia also had a significant influence, and eating fish more than once a week had a protective effect. No effect of parental smoking, gender or race was found. In adults, BHR was associated with being female and with smoking history. It appears that many factors have a significant influence on the presence of BHR, with environmental factors, particularly atopy, birthplace and diet, being the most important.
