We determined multivariate logistic regression models predicting affirmative answers to the questions “Have you ever had asthma (chronic bronchitis or emphysema) confirmed by a doctor?” (Table 5). As expected, asthma was very strongly associated with attacks of wheezing with dyspnea. Those with a history of asthma were 3.5 times more likely to have baseline airways obstruction detected by spirometry. Asthma was associated with fewer pack-years of smoking and less likely in Pittsburgh (clinic P).
A diagnosis of chronic bronchitis was independently associated with a low FEVi, current smoking of 20 cigarettes or more per day, increased body weight, and high school or college education (when compared with less education). When all of these factors were taken into consideration, women were twice as likely as men to have chronic bronchitis, and participants from Pittsburgh were significantly less likely.
A diagnosis of emphysema, as reported by 4.7 percent of our participants, was independently associated with a low FEVi, higher pack-years of smoking, lower body weight, and symptoms of attacks of wheezing and DOE. Elderly men were twice as likely as elderly women to have a diagnosis of emphysema, even when all of the above variables were taken into consideration in the model. buying antibiotics online
We were interested in the group of participants who had airflow limitation (obstruction) on spirometry, but who did not have a physician diagnosis of obstructive lung disease (asthma, chronic bronchitis, or emphysema). Obstruction was defined as the FEVi/FVC and the FEVi both below the lower limit of the normal range, based on our internally generated reference equations. Undiagnosed airways obstruction was more than five times as likely in current smokers and three times as likely in former smokers, compared with never smokers, and positively associated with pack-years of smoking.
Table 5—Predictors of Physician-Diagnosed Lung Diseases and Undiagnosed Airways Obstruction, Using Stepwise Logistic Models
|Asthma (ATS Q#20C)|
|Chronic bronchitis (ATS Q#18C)|
|Smoked >1 pack per day||1.5||1.2-1.9||<0.001|
|Weight, +10 kg||1.06||<0.001|
|High school education||1.4||1.1-1.8||0.008|
|Emphysema (ATS Q#19C)|
|Dyspnea, grade 3+||2.4||1.7-3.5||<0.001|
|Weight, +10 kg||0.895||0.84-0.95||<0.001|
|Height, +10 cm||1.25||1.01-1.55||0.043|