Table 2 Presence of baseline host characteristics and their association with incident work-related lower respiratory symptoms and work-related rhinoconjunctivitis symptoms

	Study cohort at inception	Subjects with incident work-related lower respiratory symptoms	p Value*	Subjects with incident work-related symptoms of rhinoconjunctivitis	p Value*
	No (%)	No (%)	p Value*	No (%)	p Value*
Number	298	13		19
Atopy	104 (34.9)	6 (46.2)	0.38	8 (42.1)	0.49
Physician-diagnosed asthma	56 (18.8)	6 (46.2)	0.01	2 (10.5)	0.34
BHR	57 (19.2)	6 (46.2)	0.01	2 (10.5)	0.37
PC20 ⩽16 mg/ml†
Non-work-related respiratory symptoms	49 (16.4)	4 (30.8)	0.15	1 (5.3)	0.17
Non-work-related symptoms of RC	101 (33.9)	7 (53.9)	0.12	4 (21.1)	0.22

*p value in χ² analysis comparing cases (with incident symptoms) with referents within the cohort; †n = 297 for methacholine bronchial challenge test.
BHR, bronchial hyper-responsiveness; PC20, provocative concentration causing a 20% decrease in forced expiratory volume in one second; RC, rhinoconjunctivitis.