Interactions between traffic air pollution and glutathione S-transferase genes on childhood asthma

Table 2 Selected characteristics for participants in Taiwan children health study n (%)

	With genotyping	All eligible participants
	(n = 3714)	(n = 5045)
Demographic information
Sex
Boys	1820 (49.0)	2436 (48.3)
Girls	1894 (51.0)	2609 (51.7)
Age, yr (mean ± SD)	12.8 ± 0.4	12.9 ± 0.6
Parental education, yr1
≤ 12	2301 (62.0)	3176 (63.5)
13-15	734 (19.8)	956 (19.1)
≥ 16	674 (18.2)	873 (17.4)
Gestational age1
Full term	3318 (90.9)	4461 (90.7)
< 4 wk early	236 (6.5)	316 (6.4)
≥ 4 wk early	98 (2.7)	142 (2.9)
Parental history of atopy1
Yes	952 (26.5)	1257 (25.9)
No	2645 (73.5)	3590 (74.1)
Family income12
≤ 400000	1233 (35.7)	1751 (37.5)
410000-800000	1402 (40.6)	1844 (39.5)
≥ 810000	822 (23.8)	1072 (23.0)
Number of siblings1
0	346 (9.3)	458 (9.1)
1	1748 (46.9)	2265 (45.0)
2	1229 (33.0)	1697 (33.7)
≥ 3	406 (10.9)	613 (12.2)
Home exposures1
Dampness at home	1915 (51.6)	2610 (51.7)
In utero exposure maternal smoking	141 (3.8)	193 (3.8)
ETS at home	1597 (43.2)	2246 (44.8)
Respiratory outcomes1
Asthma	289 (7.8)	372 (7.4)
Asthma under medication	95 (2.6)	122 (2.4)
Wheeze	443 (12.0)	583 (11.6)
Early-onset asthma	186 (5.2)	239 (4.9)
Late-onset asthma	95 (2.7)	121 (2.5)
Active asthma	136 (3.7)	168 (3.4)
Genetic markers1
GSTP1
Ile/Ile	2433 (65.5)
Ile/Val	1132 (30.5)
Val/Val	149 (4.0)
GSTM1
Present	1596 (43.0)
Null	2118 (57.0)
GSTT1
Present	1923 (51.8)
Null	1791 (48.2)

¹Number of subjects do not add up to total N because of missing data;

²New Taiwan dollars per year ($1 US = $ 33 New Taiwan). ETS: Environmental tobacco smoke.