Table 3

Proportional hazards model for death among all subjects in univariate and multivariate models

Univariate modelsMultivariate model*
Hazards ratio95% CIHazards ratio95% CI
*Models adjusted for lung function category, age, race, sex, education, smoking status, pack years of smoking, years since regularly smoked, and body mass index.
**Severe COPD = forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <0.70 and FEV1 <50% predicted; moderate COPD=FEV1/FVC <0.70 and FEV1 ⩾50–<80% predicted; mild COPD=FEV1/FVC <0.70 and FEV1 ⩾80%; symptoms only=presence of respiratory symptoms in the absence of any lung function abnormality; restrictive lung disease=FEV1/FVC ⩾0.70 and FVC <80% predicted.
From the First National Health and Nutrition Examination Survey 1971–5 and follow up to 1992.
Lung function
    Severe COPD**6.65.1 to 8.62.72.1 to 3.5
    Moderate COPD3.53.0 to 4.21.61.4 to 2.0
    Mild COPD2.42.0 to 2.91.21.01 to 1.4
    Respiratory symptoms only1.31.1 to 1.51.20.97 to 1.4
    Restrictive lung disease2.62.3 to 3.21.71.4 to 2.0
    No lung disease1.01.0
Age
    25–391.01.0
    40–493.02.3 to 4.12.72.0 to 3.6
    50–597.25.6 to 9.36.05.0 to 7.9
    60–6917.913.9 to 22.916.312.6 to 21.2
    70–7437.829.1 to 49.137.128.1 to 49.0
Race
    White1.01.0
    Non-white1.41.2 to 1.61.20.97 to 1.4
Sex
    Male1.61.5 to 1.81.61.4 to 1.9
    Female1.01.0
Education
    ⩽12 years1.81.5 to 2.01.21.01 to 1.4
    ⩾13 years1.01.0
Smoking status
    Current smoker1.31.2 to 1.51.41.2 to 1.7
    Former smoker1.41.2 to 1.61.10.9 to 1.4
    Never smoker1.01.0
Pack years
    Never smoker1.0
    <300.80.7 to 0.91.0
    30–<601.81.6 to 2.11.31.1 to 1.6
    ⩾602.72.3 to 3.21.31.1 to 1.5
Years since regularly smoked
    Never smoker1.0
    01.71.4 to 2.11.31.0 to 1.7
    0–<101.21.0 to 1.51.00.8 to 1.2
    ⩾101.31.2 to 1.51.0
Body mass index (kg/m2)
    <18.51.71.3 to 2.31.71.3 to 2.3
    ⩾18–241.01.0
    25–291.31.2 to 1.51.00.9 to 1.2
    ⩾301.71.4 to 1.91.41.2 to 1.7