Incidence of GOLD-defined chronic obstructive pulmonary disease in a general adult population.
METHODS
The incidence of chronic obstructive pulmonary disease (COPD) as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) has not previously been examined.


OBJECTIVE
To estimate cumulative 9-year GOLD-defined COPD incidence in a general adult Norwegian population, to analyse sex, age, smoking habits and residential area as predictors, and to assess the level of underdiagnosis.


METHODS
Based on a random stratified population sample examined in 1987-1988, 908 adults (71%) participated in a follow-up examination in 1996-1997. Associations between risk factors and COPD incidence were examined with logistic regression analyses.


RESULTS
The cumulative incidence of COPD among persons at risk in 1987-1988 was 6.1% (95% confidence interval [CI] 4.0-8.1). Adjusted odds ratios (OR) for current smokers and ex-smokers were 9.6 (95% CI 3.6-25.2) and 5.0 (95% CI 1.8-13.8), compared to never smokers. Risk for COPD incidence further increased with pack years. Subjects aged 45-74 had an OR of 9.8 (95% CI 4.3-22.5) relative to those aged 18-44. Sex and residential area were not significantly associated with COPD incidence. Only 43% of the incident cases had physician-diagnosed asthma, bronchitis, emphysema and/or COPD.


CONCLUSIONS
Approximately 6% developed COPD over 9 years. Smoking and aging were important incidence predictors. Our study suggests a substantial underdiagnosis of COPD among adults in this community.
Johannessen
A
A
Institute of Medicine, University of Bergen, Bergen, Norway. Ane.Johannessen@helse-bergen.no
Omenaas
E
E
Bakke
P
P
Gulsvik
A
A
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology*; D012016:Reference Values; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects