Smoking, respiratory symptoms, and diseases

Study objectives: The influences of different smoking categories on the pre valence of respiratory symptoms, asthma, and chronic bronchitis have been e xamined in the most northern province of Sweden, Norrbotten, and in Lapland , Finland. The two areas have similar geographic and demographic conditions . Methods and study population: The study; is a part of the FinEsS studies, w hich are epidemiologic respiratory surveys in progress in Sweden, Finland, and Estonia. A random sample of 20- to 69-years-olds were invited to answer a postal questionnaire about respiratory symptoms, smoking habits, and occ upation, In Norrbotten, 8,333 subjects were invited and 7,104 responded (85 %). In Lapland, 8,005 were invited and 6,633 responded (83%). Results: The participation by age and sex was similar in both countries. Th e prevalence of smokers in Lapland was 32% vs 26% in Norrbotten. Significan tly more women than men in Norrbotten were smokers, while the opposite was true for Lapland. Sputum production was the most prevalent symptom in both areas, 25% in Lapland vs 19% in Norrbotten. The prevalence of chronic produ ctive cough was 11% in Lapland and 7% in Norrbotten. Bronchitic symptoms we re more prevalent in Lapland among both smokers and nonsmokers. A positive family history of chronic obstructive airway disease together with increase d number of consumed cigarettes showed an additive effect for both; chronic productive cough and wheezing. The odds ratio (OR) for wheezing during the last 12 months was 3.8 for subjects without a family history of obstructiv e airway disease who consumed > 14 cigarettes per day compared with nonsmok ers, but if the subjects had a family history of obstructive airway disease , the risk for wheezing increased to OR 8.4. Conclusion: Bronchitic symptoms were more common in Finland. The difference remained also after correction for demographic variables including smoking habits, age and socioeconomic group, and family history of obstructive air way disease. Identical methods, sample composition, and the high participat ion rate contribute to the validity of the results. Air pollution, includin g environmental tobacco, smoke, may contribute to the difference. To explai n the difference, further analysis and investigations of social and environ mental factors as well as genetic factors are needed.