Seroprevalence of Chlamydia pneumoniae antibodies in a young adult population sample living in Verona. European Community Respiratory Health Survey (ECRHS) Verona.

The aim of the study was to evaluate the prevalence of antibodies to Chlamydia pneumoniae in a random population sample of 369 young adults (aged 20-44 years), living in Verona, Italy. IgG and IgM titers were measured by micro-immunofluorescence. IgG antibodies, greater or equal to 16, were found in 104/177 (58.8%) men and 76/192 (39.6%) women (p < 0.001). No relationship was found between IgG seropositivity, age, social class, education and family size. Factors positively associated with IgG seropositivity included smoking (p < 0.001), occupational status (employed vs unemployed: p = 0.02; students vs unemployed: p < 0.01) and living area (suburban [65.0%] vs urban area [45.3%]: p = 0.03). The geometric mean of IgG titers was higher in students (GM: 26.05) than in both employed (GM: 11.02) and unemployed persons (GM: 4.80) (p < 0.01 and p < 0.001, respectively). IgG titres > or = 512 and/or IgM titers > or = 16 (suggestive of a recent C. pneumoniae infection) were found in 39 subjects (10.6%). Recent infection was more frequent in spring (14.9%), with no significant variation in the other seasons (mean prevalence 6.7%) (p < 0.01). Recent infection was also associated with cigarette smoking. On the other hand, no significant association was found between respiratory symptoms and serologic evidence of recent infection.

CONCLUSIONS

1) the prevalence of antibodies to C. pneumoniae in young adults from Verona is similar to that found in European countries, and therefore, in Europe, it seems not related to latitude or climate; 2) male sex, tobacco smoking, employment status and living in a suburban area are independent risk factors of infection; 3) the infection is subclinical in most cases.