Respiratory virus antibodies in adults of a Norwegian community: prevalences and risk factors.

BACKGROUND

The aims were to examine prevalences as well as demographic and environmental predictors of respiratory virus antibodies in serum.

METHODS

In a cross-sectional study of 18-73 year old Norwegian adults a random stratified sample (n = 1512) was invited to attend an examination at an outpatient clinic. Seven respiratory virus antibodies were assessed by the complement fixation test.

RESULTS

The attendance rate was 84%. The most frequent virus antibodies with titre of > or = 1:8 were influenza virus type A with a population standardized prevalence of 44%, adenovirus 25% and influenza virus type B 22%. The prevalences of antibodies against parainfluenza virus type 1, 2 and 3 increased with age. Smokers compared to non-smokers had an adjusted odds ratio (OR) of 1.7 (95% confidence interval [CI]: 1.3-2.4) for having one or more of the seven examined virus antibodies. The presence of one or more of the virus antibodies increased from summer to winter months (adjusted OR = 1.3 per month; 95% CI: 1.2-1.4) and it was higher in occupational dust or gas exposed smokers (adjusted OR = 2.0; 95% CI: 1.1-3.7) compared with unexposed smokers.

CONCLUSIONS

Ageing, smoking, occupational dust or gas exposure as well as season of the year may thus be predictors for levels of respiratory virus antibodies in adults. These observations should be taken into account when comparing prevalences of virus antibodies in various communities as well as when examining the relationship between presence of virus antibodies and airway disease.