Pulmonary effects of intermittent, seasonal exposure to high concentrations of cotton dust

Table 4 Association between exposure to cotton dust and duration of exposure with changes in the pulmonary function test parameters¹ (n = 51)

Period of time	Parameters	Independent variable	Adjusted R2	β
At the beginning of work season	VCb	Duration of exposure	0.23	-0.5
	FVCb		0.4	-0.65
	FEV1b		0.21	-0.48
	FEV1/FVCd		0.16	0.42
During the work shift	FVCa	Duration of exposure	0.06	-0.28
During the work shift	FEV1d	Dust concentration	0.14	0.4
During the work season	VCd	Dust concentration	0.1	0.4
	FVCd		0.1	0.32
	FEV1a		0.06	0.28

¹Multiple linear regression analysis;

^bP < 0.001;

^dP < 0.01;

^aP < 0.05. VC: Vital capacity; FVC: Forced vital capacity; FEV: Forced expiratory volume.