Influence of heavy traffic, city dwelling and socio-economic status on nasal symptoms assessed in a postal population survey.

BACKGROUND: The association between social position, living environment and nasal symptoms is inconsistent. We wanted to test how living environment, occupation and social position were associated with nasal symptoms.
METHODS: In a postal survey study of a random sample of 12,079 adults, aged 20-59 years living in the southern part of Sweden the relationship between nasal symptoms, socio-economic status and environmental factors was analysed.
RESULTS: The response rate was 70% (n = 8469) of whom 33% reported significant nasal symptoms. Nasal discharge, thick yellow discharge, a blocked nose, sneezing and itching were strongly associated with living close to heavy traffic or living in cities. Most of the nasal symptoms provoked by extrinsic factors were more frequently reported among subjects who lived close to heavy traffic and in cities. Apart from thick yellow discharge and nasal symptoms provoked by damp/cold air which were more common in the socio-economic position "low" no relation to the socio-economic group was found. The prevalence of self-reported hay fever was neither affected by site of living nor by socio-economic status. Nasal symptoms evoked by "allergic" factors were linked to asthma but symptoms evoked by non-allergic factors were linked to chronic bronchitis/emphysema CBE.
CONCLUSIONS: To conclude, we found a strong relation between geographical site and the prevalence of self-reported nasal symptoms which emphasizes the environment as a risk factor for nasal symptoms. Only by merging the socio-economic groups into "low" and "middle/high" an association to nasal symptoms was apparent. Nasal symptoms evoked by "allergic" factors were linked to asthma but symptoms evoked by "non allergic factors" were linked to CBE.