Sensitisation to airborne moulds and severity of asthma: cross sectional study from European Community respiratory health survey
Mahmoud Zureik, epidemiological researcher a, Catherine Neukirch, senior physician in allergology a, Bénédicte Leynaert, epidemiological researcher a, Renata Liard, epidemiologist a, Jean Bousquet, professor b, Françoise Neukirch, senior epidemiological researcher a, on behalf of the European Community Respiratory Health Survey.
a National Institute of Health and Medical Research (INSERM), Unit 408 Epidémiologie, Faculté de Médecine Xavier Bichat, BP 416, 75870 Paris CEDEX 18, France, b National Institute of Health and Medical Research (INSERM), Unit U454 Hôpital Arnaud de Villeneuve, 34295 Montpellier Cedex 05, France
Correspondence to: Mahmoud Zureik zureik@vjf.inserm.fr
Objective: To assess whether the severity of asthma is associated with sensitisation to airborne moulds rather than to other seasonal or perennial allergens.
Design: Multicentre epidemiological survey in 30 centres.
Setting: European Community respiratory health survey.
Participants: 1132 adults aged 20-44 years with current asthma and with skin prick test results.
Main outcome measure: Severity of asthma according to score based on forced expiratory volume in one second, number of asthma attacks, hospital admissions for breathing problems, and use of corticosteroids in past 12 months.
Results: The frequency of sensitisation to moulds (Alternaria alternata or Cladosporium herbarum, or both) increased significantly with increasing asthma severity (odds ratio 2.34 (95% confidence interval 1.56 to 3.52) for either for severe v mild asthma). This association existed in all of the study areas (gathered into regions), although there were differences in the frequency of sensitisation. There was no association between asthma severity and sensitisation to pollens or cats. Sensitisation to Dermatophagoides pteronyssinus was also positively associated with severity. In multivariable logistic regressions including sensitisation to moulds, pollens, D pteronyssinus, and cats simultaneously, the odds ratios for sensitisation to moulds were 1.48 (0.97 to 2.26) for moderate v mild asthma and 2.16 (1.37 to 3.35) for severe v mild asthma (P<0.001 for trend).
Conclusions: Sensitisation to moulds is a powerful risk factor for severe asthma in adults. This should be taken into account in primary prevention, management, and patients' education.
The severity of asthma varies widely between patients. Mild cases are characterised by normal lung function and patients are asymptomatic most of the time, whereas severe cases are characterised by permanently impaired lung function and frequent exacerbations. Little is known about the factors associated with severity, but the identification of such factors is necessary for management and prevention.
Sensitisation to airborne allergens might be involved in the underlying mechanisms of severity. The associations between exposure, sensitisation, and asthma have suggested that house dust mite, 1 2 animal dander, 3 4 cockroaches,5 pollens,6 and mould spores7 have a causal role in development. However, the associations between sensitisation to different allergens and the severity of asthma have been poorly explored.
Sensitisation to moulds has been suggested as a risk factor for life threatening asthma.8-10 However, the hypothesis that such sensitisation is generally associated with the severity of asthma remains to be investigated.
We used data from 1132 people with asthma from the entire dataset of the European Community respiratory health survey to assess whether the severity of asthma is associated with sensitisation to airborne moulds rather than to other seasonal or perennial allergens.
The methods of the survey have been fully described elsewhere. 11 12 Briefly, participating centres randomly selected samples of 20 to 44 year olds, who completed a short postal questionnaire about asthma and asthma-like symptoms (stage 1). At stage 2 a random subsample of responders were invited to complete a more detailed questionnaire and undergo skin prick and blood tests, assessment of lung function by spirometry, and airway challenge with methacholine.
For full article, contact:
Vik Ahuja
Pure Air Control Services
(800) 422-7873, ext. 804
