Table 5

Bronchial responsiveness in historical controls (HC) and in the study group stratified by exposure to wood dust expressed in terms of the cumulative dust exposure index

Variable		HC		Exposure (y.mg/m³)		p Value^5-150		p Value^5-151
Variable		HC		0	⩽70	p Value^5-150		p Value^5-151	70–110	110–160	<160
n	200	13	28	28	25	33	—	—
MBC+ n (%)	20 (10)	1 (8)	4 (14.3)	6 (21.4)	6 (21.4)	9 (27.3)	0.77^5-152	0.002^5-152
DRS (mean (SD))	0.28 (0.08)	0.31 (0.08)	0.27 (0.07)	0.25 (0.08)	0.25 (0.09)	0.24 (0.1)	0.04^5-153	0.014^5-153

↵5-150 HC excluded from the analysis.
↵5-151 HC included in the analysis.
↵5-152 Logistic regression after adjustment for baseline FEV₁and age.
↵5-153 Linear regression after adjustment for FEV₁ and age.
MBC+=decline in FEV₁ by ⩾20%; DRS=1/(% decline in FEV₁/μmol +2.5).