Background: in order to describe the prevalence and prognostic implications of chronic bronchitis in individuals 65 years or older we analysed data from The Copenhagen City Heart Study.
Methods: the population was studied in 1976-1978 resurveyed in 1981-1983 and 1991-1994 and followed with regard to survival for up to 12 years. Approximately 3,700 elderly participants with a mean age of 76 years were available for analyses.
Results: the prevalence of chronic bronchitis was 13.0% in women and 18.6% in men. Multiple logistic regression yielded the following predictors for chronic bronchitis: male gender (odds ratio with 95% confidence interval = 1.1 (0.9-1.3)), previous smoking odds ratio = 1.7 (1.2-2.2), present smoking odds ratio = 2.1 (2.1-3.8), previous exposure to dusts and fumes (odds ratio = 2.2 (1.7-2.7)), chest infections in childhood (odds ratio = 2.1 (1.6-2.9)), more than 6 chest infections in previous 10 years (odds ratio = 6.2 (4.1-9.2)) and alcohol consumption of more than 3 drinks a day (odds ratio = 1.8 (1.3-2.3)). Chronic bronchitis was a significant predictor of both subsequent respiratory infections and survival. After adjustment for age, smoking and lung function, a Cox regression showed that chronic bronchitis was significantly related to mortality from all causes with a hazard ratio with 95% confidence interval = 1.3 (1.1-1.4), all benign respiratory diseases (hazard ratio = 2.0 (1.6-2.7)), obstructive lung disease (hazard ratio = 2.5 (1.7-3.6)) and lung cancer (hazard ratio = 2.0 (1.4-2.9)).
Conclusions: in an elderly population, chronic bronchitis is a prevalent condition with important prognostic implications.