Table 2.

Estimates for the interaction between gas cooking and genetic variants in GSTM1, GSTT1 and GSTP1 on bronchial responsiveness in the European Community Respiratory Health Survey II

Genetic variant	Whole sample			‘Random’ sample			‘Enriched’ sample*
	N	β (95% CI)	p Value	N	β (95% CI)	p Value	N	β (95% CI)	p Value
GSTM1 null	2208	−0.75 (−1.16 to −0.33)	4×10−4	1843	−0.81 (−1.34 to −0.28)	0.003	365	−0.93 (−2.01 to 0.14)	0.088
GSTT1 null	2208	−0.02 (−0.54 to 0.50)	0.929	1843	−0.27 (−0.83 to 0.28)	0.336	365	0.74 (−0.57 to 2.04)	0.270
GSTP1-rs1695	2444	0.03 (−0.41 to 0.46)	0.905	2018	0.01 (−0.45 to 0.48)	0.954	426	0.31 (−0.48 to 1.11)	0.441

*France and Switzerland were considered as one group due to small numbers in those two countries.