Background: Few epidemiological surveys on general population samples estimated changes in prevalence of respiratory symptoms/diseases over a long time interval; our study aims to quantify the temporal changes in the prevalence rates of asthma, allergic rhinitis and Chronic Obstructive Pulmonary Disease (COPD) after 25 years from baseline.
Methods: A general population sample participated in 3 cross-sectional surveys carried out in Central Italy (Pisa) in 1985-88 (n = 3865), 1991-93 (n = 2841), 2009-11 (n = 1620). 2276 (47%) subjects participated in at least 1 survey, 1723 (35.5%) in at least 2 surveys and 849 (17.5%) in all the 3 surveys. All subjects filled in a standardized questionnaire about health status and risk factors; a sub-sample performed spirometry. Chi-square test was used to compare adjusted prevalence rates of respiratory symptoms/diseases and descriptive characteristics among the surveys. Generalised estimating equations (GEE) were used to analyze the association between respiratory symptoms/diseases and risk factors.
Results: There was an increasing trend in prevalence rates of all respiratory symptoms/diseases throughout the surveys: current asthma attacks (1st-3rd survey prevalence: 3.4-7.2%), allergic rhinitis (16.2-37.4%), usual phlegm (8.7-19.5%) and COPD (2.1-6.8%) more than doubled. The GEE model confirmed these increasing trends, indicating higher risk of having respiratory symptoms/diseases in the second and third surveys.
Conclusions: While asthma and allergic rhinitis increasing trends were confirmed, with respect to other international studies, also a COPD increasing prevalence rates was shown.
Keywords: General population; Prevalence trends; Risk factors.
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