Table 5

Multivariate regression analysis to examine dust exposure, age, and smoking as a predictors of lung function

Covariates		Dependent
		VC				FVC				FEV₁
		β	SE			p Value	β			SE	p Value	β	SE	p Value
Intercept	3.767	0.184	0.000		3.902	0.206	0.000		3.635	0.202	0.000
Dust 1 (dummy)	0.458	0.124	0.000		0.352	0.138	0.012		−0.141	0.135	0.300
Dust 2 (dummy)	0.187	0.092	0.044		0.231	0.103	0.027		−0.103	0.101	0.310
Age	−0.019	0.005	0.000		−0.022	0.006	0.000		−0.025	0.006	0.000
Pack-years	−0.276	0.072	0.000		−0.250	0.080	0.002		0.157	0.079	0.047

Intercept	3.789	0.191	0.000		3.922	0.210	0.000		3.648	0.203	0.000
Dust 1 (dummy)	0.478	0.128	0.000		0.370	0.141	0.009		−0.129	0.136	0.344
Dust 2 (dummy)	0.223	0.095	0.020		0.264	0.105	0.013		−0.082	0.101	0.419
Age	−0.023	0.005	0.000		−0.025	0.006	0.000		−0.028	0.006	0.000
	PEF			FEV₁/FVC			FEV₁/VC
Intercept	492.7	45.69	0.000		95.95	4.71	0.000		99.42	4.97	0.000
Dust 1 (dummy)	−148.9	30.66	0.000		−14.47	3.16	0.000		−16.97	3.34	0.000
Dust 2 (dummy)	−136.5	22.90	0.000		−10.25	2.36	0.000		−8.63	2.49	0.001
Age	−1.700	1.28	0.186		−0.223	0.13	0.094		−0.295	0.14	0.036
Pack-years	−21.79	17.86	0.224		0.781	1.84	0.672		1.963	1.94	0.314

Intercept	494.43	45.72	0.000		95.89	4.69	0.000		99.26	4.97	0.000
Dust 1 (dummy)	−147.4	30.67	0.000		−14.5	3.15	0.000		−17.12	3.33	0.000
Dust 2 (dummy)	−133.6	22.81	0.000		−10.4	2.34	0.000		−8.89	2.48	0.000
Age	−1.966	1.256	0.122		−0.213	0.13	0.103		−0.271	0.137	0.050

Dust exposure (1=low exposure, 2=mild exposure, 3=high exposure).
Low dust exposure is reference group; dust1 (dummy)=mild exposure; dust2 (dummy)=high exposure.