Prevalence rates of diagnosis of asthma in general population samples of Northern and Central Italy

In order to assess the distribution of asthma in Italy in the 1980s, we have compared the findings of three general population surveys carried out in the North and the Centre of the country. Two cross-sectional investigations were performed in the Po Delta area (North Italy), 6 yrs apart: 1) 3,285 subjects, aged 8-64 yrs, in 1980-1982 (PD1); and 2) 2,841 subjects, aged 8- 73 yrs, in 1988-1991 (PD2). One cross-sectional survey was carried out in Pisa (Central Italy): 3,866 subjects, aged 5-90 yrs, in 1985-1988 (PI1). For this analysis we have used data from the standardized questionnaires of those subjects between 18-64 yrs, who were currently employed. The prevalence rate of ever asthma was 3.3-5.5%, that of current asthma 1.3-2.9%; almost all of the diagnoses were confirmed by a doctor. Taking into account only doctor- confirmed asthma, the age of onset of manifestations was most frequently over 18 yrs (41-79%). It also occurred more frequently after the onset of employment. As regards smoking, whilst most asthmatic males were current or former smokers (70-86%), most asthmatic females were non-smokers. However, the situation changed in PD2, where females showed the same pattern as males. Considering asthmatic subjects with skin-prick test reactivity (data available only in PD2), the vast majority (67% in males, 75% in females) had an age of disease onset under 18 yrs. In conclusion, the prevalence of asthma in Italy in the 1980s was similar to that in other European countries and was affected by atopy and smoking differently in the two sexes. A possible relationship with occupational history is worth further assessment.