Background: The incidence of chronic obstructive pulmonary disease (COPD) is little investigated. This study assessed the incidence of a self-reported physician's diagnosis of chronic bronchitis and/or emphysema (CBE) and/or COPD (CBE/COPD), and investigated the effects of a family history of CBE in 1992 and change in smoking habits (assessed in 1992 and 2000) on this incidence.
Methods: A follow-up study in 2000 of 4933 subjects who responded to a respiratory questionnaire study in 1992 was performed. Response rate was 86.8%. Odds ratios (ORs) for incident cases of CBE/COPD were calculated by multiple Logistic regression.
Results: The cumulative incidence of a physician's diagnosis of CBE/COPD was 2.9%. A family history of CBE predicted incident cases of CBE/COPD, OR 2.7 (95% CI 1.5-5.1). Also continuous smoking, relapse into smoking, or having stopped smoking between 1992 and 2000 had elevated ORs for incident cases of CBE/COPD, 2.6 (1.4-4.7), 7.2 (2.7-18.7), and 2.6 (1.3-5.3), while the OR for ex-smoking in 1992 as well as 2000 was 0.9 (0.4-1.8).
Conclusions: A family history of CBE increases the risk for development of CBE/COPD. Sustained smoking cessation over many years may be required to significantly reduce the risk of developing CBE/COPD.