Prevalence rates of respiratory symptoms and diseases in general population samples of North and Central Italy

SETTING: Four cross-sectional general population surveys in Italy: northern rural Po Delta area (1980-1982, n = 3284; 1988-1991, n = 2841), and central urban Pisa area (1985-1988, n = 3865; 1991-1993, n = 2841). OBJECTIVE: To analyse changes in prevalence rates of respiratory symptoms and diseases. DESIGN: Prospective epidemiological studies by standardized interviewer-administered questionnaire. RESULTS: Prevalence rates of respiratory symptoms and diseases tended to be higher in males (except for dyspnea and pleuritis), in the urban area (more polluted), and in the second surveys; moreover, they increased with age. Asthma peaked in those aged under 25 years and over 64 years. The highest prevalence rates were shown by current smokers of both sexes for all respiratory symptoms and by ex-smoker males for all respiratory diseases, while female current smokers reported chronic bronchitis, emphysema and asthma more frequently. The most clear-cut trend towards increase between the two surveys within each area was exhibited by wheeze and asthma. CONCLUSIONS: These findings highlight the relevance of sex, age and smoking habit, as well as the possible effects of air pollution, in relation to respiratory symptoms. They also indicate a trend towards an increase in asthma symptoms in Italian general population samples in the 1990s, and an underestimate of medically diagnosed chronic respiratory diseases.