Prevalence of asthma and asthma symptoms in a general population sample from northern Italy

The European Community Respiratory Health Survey is an international survey of the general population which aims to establish whether there are significant variations in the prevalence of asthma among European countries. The present paper reports the prevalence of asthma and asthma-like symptoms in a sample of subjects living in three areas of northern Italy: Turin, Pavia, and Verona. Samples of residents 20–44 years old (3000 subjects in Turin and Verona and 1000 in Pavia) stratified by sex (M:E= 1/1) were randomly selected from local health authority lists in the three participating areas. To correct the observed prevalence estimate for nonresponse bias, a method proposed by Drane was applied. Of the sampled subjects, 86% (6031) participated in the survey. Two different definitions of asthma were adopted: 1) prevalence of asthma attack in the last 12 months; 2) prevalence of asthma attack or treatment with antiasthmatic drugs, or both wheezing apart from the common cold and wheezing with shortness of breath. This combination of symptoms has been called current asthma. According to these definitions, the prevalence of asthma attack was 3.47% (3.74%, in men and 3.14% in women), and the prevalence of current asthma was 5.01% (5.07% in men and 4.90% in women). The lowest prevalence was found in Pavia; the highest in Turin. Our findings support the hypothesis that the difference in prevalence reflects the difference in mortality.