Table 1—

Characteristics of the study sample according to confounding variables and their association with Composite Household Chemical Exposure(CHCE) score

Young malesYoung femalesCHCE
Maternal smoking during pregnancy cigarettes·day−1
 None3057 (85.2)2858 (85.4)9.1±4
 1–9234 (6.5)202 (6.0)10.3±4
 ≥10296 (8.3)286 (8.5)11.1±4
Exposure to environmental tobacco smoke
 No2563 (69.7)2323 (67.6)9.0±4
 Yes1116 (30.3)1111 (32.4)10.2±4
Damp housing
 No1782 (49.9)1752 (52.2)9.6±4
 Yes1787 (50.1)1607 (47.8)9.1±4
Pets in home
 No1670 (46.7)1555 (46.2)9.1±4
 Yes1907 (53.3)1810 (53.8)9.8±4
Maternal history of asthma
 No3257 (88.8)3033 (89.0)9.4±4
 Yes410 (11.2)375 (11.0)9.5±4
Maternal age at delivery yrs
 <25521 (14.0)539 (15.6)10.4±4
 ≥253190 (86.0)2912 (84.4)9.2±4
Maternal highest education
 None/CSE487 (13.3)464 (13.6)10.7±4
 Vocational315 (8.6)281 (8.3)10.6±4
 O-level1325 (36.3)1194 (35.1)9.9±4
 A-level938 (25.7)902 (26.5)8.9±4
 Degree590 (16.1)563 (16.45)7.1±4
Housing tenure
 Mortgage owned3025 (84.6)2788 (82.8)9.2±4
 Council rented306 (8.6)303 (9.0)11.3±5
 Other245 (6.9)278 (8.3)8.8±4
Crowding in home persons per room
 ≤0.5555 (15.8)509 (15.4)8.7±4
 0.5–0.751356 (38.7)1299 (39.4)9.2±4
 0.75–11199 (34.2)1142 (34.6)9.7±4
 >1394 (11.2)347 (10.5)10.1±4
Maternal parity
 01651 (45.3)1569 (46.4)9.1±4
 11290 (35.4)1227 (36.3)9.6±4
 ≥2707 (19.4)585 (17.3)9.8±4
Maternal hours worked outside home
 Doesn't work1780 (51.2)1657 (51.1)9.5±4
 <10276 (7.9)278 (8.6)9.3±4
 10–20748 (21.5)732 (22.6)9.5±4
 20–30329 (9.5)266 (8.2)9.1±4
 ≥30345 (9.9)309 (9.5)8.7±4
Season of questionnaire
 January–April1461 (39.7)1377 (40.3)9.2±4
 May–August1226 (33.3)1137 (33.3)9.8±4
 September–December991 (26.9)902 (26.4)9.3±4
  • Data are presented as n (%) or mean±sd.