No change in prevalence of symptoms of COPD between 1996 and 2006 in Finnish adults – a report from the FinEsS Helsinki Study

BACKGROUND: The age-dependent increase of chronic obstructive pulmonary disease (COPD) prevalence caused by smoking and other inhalational exposures in the general population is well-known worldwide. However, time trends are poorly known, due to lower number of high-quality studies especially following nationwide efforts on diminishing exposure levels. This study aimed to compare the prevalence of COPD symptoms and their major determinants in Finnish adults in 1996 and 2006. METHODS: Two identical postal surveys were conducted among two random population samples from Helsinki using identical methodologies in 1996 and 2006, with 6,062 (76%) and 2,449 (62%) participants, respectively. RESULTS: The physician-diagnoses of COPD remained at 3.7%, whereas physician-diagnoses of asthma and use of asthma medicines increased in both genders. Current smoking reduced from 33.4 to 27.3% (p<0.001), and the amount of cigarettes smoked also reduced significantly. The crude prevalence of chronic productive cough was 12.1 and 11.1%, wheezing with dyspnoea without a cold (wheezing triad) 7.3 and 7.7%, and dyspnoea grade II 13.8 and 13.6%, in 1996 and 2006, respectively. Among subjects with physician-diagnosed COPD, the prevalences of chronic productive cough and recurrent wheeze reduced significantly, from 60.6 to 40.7% and 53.5 to 38.5%, respectively. CONCLUSION: From 1996 to 2006, the prevalence of obstructive airway symptoms common in different phenotypes of COPD did not increase in Finnish adults. This suggests that the upward trend of COPD prevalence might have reached a plateau. Current smoking and the quantities smoked diminished suggesting a wider impact of stronger legislation and smoking-cessation efforts during the Finnish National Programme for COPD.