Table 1

Characteristics of subjects from the two surveys of the European Community Respiratory Health Survey (ECRHS) included in the present analysis

ECRHS I (N=2621)*ECRHS II (N=2546)*
Age, mean (SD)34.2 (7.2)42.2 (7.2)
Sex (%)
Smoking status (%)
 Never smoker42.9%42.9%
 Ever smoker57.1%57.1%
Smoking pack-years, mean (SD)7.8 (12.5)11.0 (17.6)
Country (%)
Cooking fuel (%)
GSTM1 genotype (%)†
GSTT1 genotype (%)†
GSTP1-rs1695 genotype (%)‡
Bronchial responsiveness, log-slope, mean (SD)7.6 (2.3)7.4 (2.3)
Fall of 20% in FEV1 after inhalation of 1 mg methacholine, PD20 (%)
Baseline FEV1, mean (SD)3.7 (0.8)3.6 (0.8)
Baseline FVC, mean (SD)4.6 (1.0)4.4 (1.0)
  • *After exclusion of subjects with missing data on cooking fuel or not using gas or electric stove, who did not perform the methacholine challenge test or had missing data on BR slope, and those with missing data on at least one of the terms in the statistical model.

  • †314 subjects from ECRHS I and 338 subjects from ECRHS II have missing data on GSTM1 and GSTT1 genotypes.

  • ‡151 subjects from ECRHS I and 102 subjects from ECRHS II have missing data on GSTP1-rs1695 genotype.