RESUMO
In this cross-sectional study we describe the prevalence and characteristics of subjects who self-reported a diagnosis of previous asthma in a sample of the Italian general population. We chose a wide age range (3-69 yrs) in order to obtain data over a large spectrum of the population. Interviews were conducted in 1,038 subjects by trained physicians using a modified version of the American Thoracic Society and National Heart & Lung Institute--Division of Lung Disease questionnaire proposed in 1978 (ATS-DLD-78). 791 subjects underwent skin prick tests for 7 common aeroallergens; 422 subjects underwent spirometry and 212 methacholine challenge tests. Cumulative prevalence of asthma was 7.9% (82/1038). Previous asthma (PA) was reported by 29 (35.4%) of the subjects, who said they had been but were no longer asthmatic; 65.5% of these claimed that PA had developed at or before the age of 14 yrs. No significant differences emerged in sex, age, family and personal history of atopy, and size of skin test reaction in subjects with PA compared to those with current asthma (CA). Although the difference was not statistically significant, the latter tended to be lifetime nonsmokers while subjects with PA were more often current smokers. Age at onset of asthma was significantly higher in subjects with CA than in subjects with PA (24.6 +/- 20 yrs vs. 12.0 +/- 15.0 yrs, p = 0.005). Bronchial hyperreactivity was present in 37.5% of subjects with PA, while forced expiratory volume in 1 sec (FEV1) was within normal limits in all. In conclusion, in this sample of the Italian population, PA was reported by about 1/3 of the asthmatic subjects, most of whom were atopic. Lung function was within normal limits in all, but bronchial hyperreactivity persisted in 1/3 subjects.