Prevalence of obstructive lung diseases and respiratory symptoms in relation to living environment and socio-economic group

We wanted to test whether living environment, occupation and social positio n are risk factors for asthma and chronic bronchitis/emphysema (CBE). The p revalence of bronchial asthma,CBE, respiratory symptoms and smoking habits in a random sample of 12071 adults aged 20-59 years was assessed in a posta l survey with a slightly modified questionnaire previously used in central and northern Sweden (The OLIN studies). Occupation was coded according to a socio-economic classification system, Six different living environment are as were defined; city-countryside, seaside-not seaside and living close to heavy traffic-not living close to heavy traffic. Multiple logistic regressi on analysis (forward conditional) was applied to estimate the association b etween the proposed set of risk factors and self-reported obstructive lung diseases and lower respiratory symptoms controlling for age, gender and smo king. After two reminders, the response rate was 70.1% (n=8469); 33.8% of t he responders were smokers. In all, 469 subjects (5.5%) stated that they ha d asthma and 4.6% reported CBE. Besides smoking, which was a risk for both asthma and CBE, there were different risk patterns for self-reported asthma and CBE, In the economically active population there was a tendency that C BE was more common among unskilled and semi-skilled workers. This fact was further emphasized when the population was merged into the two groups low s ocial position' and 'middle/high social position, with 'low social position ' as a risk for CBE (OR=1.35,95% CI = 1.06-1.72). No social risk factors we re identified for asthma. Living close to heavy traffic was a risk factor f or asthma (OR=1.29, 95% CI =1.02-1.62) but not for CBE. Apart from this no living environmental risk factors for obstructive pulmonary diseases were i dentified. Asthma symptoms and long-standing cough were more common among t hose subjects living close to heavy traffic compared to those not living cl ose to heavy traffic. To conclude, low social position was a risk factor fo r CBE and living close to heavy traffic was a risk factor for asthma. (C) 2 001 Harcourt Publishers Ltd.