Lung function, asthma paradox, atopy, and risk factors in Mexican spirometry-diagnosed asthmatic patients.

Despite long-term studies, still not much is known about the asthma triggering factors and its sometimes controversial results. Probably one of the major problems of controversy is the lack of specific and accurate diagnosis of this disease. The aim of this study was to assess lung function, atopy, and environmental factors in spirometry-diagnosed asthmatic patients. Time series of daily counts of hospital emergency admissions were constructed for known asthmatic subjects. Spirometry, chest radiograph, arterial gasometry, skin tests, environmental SO 2 levels, and climatic parameters were evaluated. Family asthma history was observed in a high proportion of asthmatic patients and it correlated marginally with severity of asthma. A seasonal trend in asthma frequency was recorded and it was more common in the urban area and in those living in the margins of the city. The most frequent asthma type recorded was the severe persistent asthma. More than 50% of subjects had subresponse to bronchodilator; asthma paradox was recorded in 10.8%. Positive skin tests were observed in 36.9% and SO 2 levels did not correlate with asthma attacks. Paradox asthma or tolerance may be developed by asthmatic subjects during chronic treatment with short-acting β 2 -agonists. To avoid side effects and to decrease the morbidity and mortality associated with the usage of antiasthma medications, it is essential to identify quickly those subjects that respond abnormally to the short-acting β2-agonist.