Table 2

Results from the random effects model for predicting forced expiratory volume in one second (FEV₁). Data from the Tucson Epidemiological Study of Airways Obstructive Disease

Variables	Coefficient	se	p‐value
Anthropometric and smoking factors
Sex (male=1)	1.303	0.037	<0.0001
Height	0.045	0.002	<0.0001
Pack-yrs of smoking	−0.005	0.0004	<0.0001
Age yrs	−0.00017	0.0012	0.147^#
Disease main effects
Asthma	−0.156	0.061	0.011
COPD	−0.135	0.065	0.038
Asthma and COPD	−0.593	0.111	<0.0001
Disease effects on rate of decline in FEV₁
Asthma by age	−0.0004	0.0011	0.722^#
COPD by age	−0.0023	0.0011	0.042
Asthma and COPD by age	0.0002	0.0015	0.867^#
COPD by sex by age²	−0.00007	0.000011	<0.0001
Interactions and nonlinear factors
Interactions with sex (males=1)
Age by sex	−0.009	0.0006	<0.0001
Asthma and COPD by sex	−0.679	0.0908	<0.0001
Nonlinear factors
Age²	−0.00017	0.000010	<0.0001

COPD: chronic obstructive pulmonary disease
^#: results not statistically significant at the α=0.05 level, indicating no increased decline in FEV₁ compared with the reference category