High prevalence of asthma and atopy in the Canary Islands, Spain.

OBJECTIVE

To evaluate the prevalence of and risk factors for asthma and related conditions in the Canaries, Spain.

METHODS

From a randomised sample of 9506 adults aged 20-44 years who answered a short questionnaire, a random sample corresponding to 20% of the original was taken. Subjects classified as symptomatic in the previous survey and who were not included in the random sample were also invited to participate. The subjects completed a respiratory questionnaire, and underwent spirometry, bronchial hyperresponsiveness (BHR) test, skin tests and immunoglobulin E (IgE) measurements.

RESULTS

The random sample included 593 subjects. The prevalence of skin sensitisation to mites was 30.3% (95%CI 26.7-34.2) and the prevalence of IgE to mites 30.5% (95%CI 26.2-35.2). A prevalence of 40.6% (95%CI 35.9-45.5) was found for atopy, 14.1% (95%CI 11.1-17.1) for BHR and 4.2% (95%CI, 2.5-5.9) for asthma. The risk factors most strongly associated with asthma were atopy (OR 4.89, 95%CI 3.07-7.78) and respiratory infection before the age of 5 years (OR 2.78, 95%CI 1.66-4.67).

CONCLUSION

This study shows a high prevalence of sensitisation to mites, atopy, BHR and asthma in the Canaries, similar to that observed in English-speaking countries. We suggest that these findings could partially result from climatic conditions.