Characteristics | Louvain-la-Neuve | Bastogne | Lessines | p-value |
Subjects | 357 | 349 | 141 | |
Males | 167 (46.8) | 130 (37.2) | 72 (51.1) | 0.006 |
Age# yrs | 15.4±0.81 | 15.5±0.83 | 15.5±0.87 | 0.54 |
BMI# kg·m-2 | 20.1±2.3 | 21.0±3.3 | 21.0±3.2 | <0.001 |
Number of older siblings# | 0.93±0.98 | 0.98±1.02 | 0.85±0.99 | 0.43 |
Parental education¶ | 278 (77.9) | 98 (28.1) | 28 (19.9) | <0.0001 |
Smokers¶ | 20 (5.6) | 14 (4.0) | 16 (11.3) | 0.007 |
Maternal smoking during pregnancy¶ | 25 (7.0) | 55 (15.8) | 25 (17.7) | 0.0002 |
Parental smoking at home¶ | 20 (5.6) | 14 (4.0) | 16 (11.3) | 0.007 |
Breastfed¶ | 305 (85.4) | 191 (54.7) | 76 (53.9) | <0.0001 |
House cleaning with bleach¶ | 77 (21.6) | 91 (26.1) | 60 (42.6) | <0.0001 |
Mould on bedroom walls¶ | 30 (8.4) | 19 (5.5) | 10 (7.1) | 0.30 |
Day care attendance¶ | 241 (67.5) | 111 (31.8) | 43 (30.5) | <0.0001 |
Swimming pool attendance | | | | |
Indoor copper–silver sanitised pool | | | | |
Attendees¶ | 339 (95.0) | 4 (1.2) | 0 (0) | <0.0001 |
CPA h+ | 225 (108–434) | 84 (46–210) | 0 (0–0) | <0.0001 |
Residential outdoor chlorinated pool | | | | |
Attendees¶ | 76 (21.3 ) | 65 (18.6) | 14 (9.9) | 0.01 |
CPA h+ | 275 (88–848) | 154 (48–412) | 232 (72–336) | 0.07 |
Nonresidential outdoor chlorinated pool | | | | |
Attendees¶ | 244 (68.3 ) | 142 (40.7) | 53 (37.6) | <0.0001 |
CPA h+ | 168 (49–336) | 126 (56–273) | 306 (108–599) | 0.0005 |
Total outdoor chlorinated pool | | | | |
Attendees¶ | 270 (75.6) | 183 (52.4) | 61 (43.3) | <0.0001 |
CPA h+ | 229 (70–477) | 147 (57–336) | 308 (134–599) | <0.0001 |
Public indoor chlorinated pool | | | | |
Attendees¶ | 243 (68.1) | 348 (99.7) | 138 (97.9) | <0.0001 |
CPA h+ | 126 (48–286) | 400 (255–657) | 407 (217–724) | <0.0001 |
Asthma¶ | | | | |
Parental asthma | 49 (13.7) | 39 (11.2) | 25 (17.7) | 0.15 |
Ever asthma | 38 (10.6) | 36 (10.3) | 14 (9.9) | 0.97 |
Current asthma | 21 (5.9) | 21 (6.0) | 10 (7.1) | 0.87 |
Aeroallergen-specific serum IgE¶ | | | | |
House dust mite | 103 (28.9) | 90 (25.8) | 32 (22.7) | 0.34 |
Dog | 15 (4.2) | 19 (5.4) | 10 (7.1) | 0.40 |
Cat | 49 (13.7) | 44 (12.6) | 14 (9.9) | 0.50 |
Pollen | 65 (18.2) | 92 (26.4) | 19 (13.5) | 0.002 |
Mould | 11 (3.1) | 6 (1.7) | 7 (5.0) | 0.14 |
At least one aeroallergen | 136 (38.1) | 136 (39.0) | 43 (30.5) | 0.19 |
Total serum IgE+ kIU·L−1 | 60.0 (22.1–173) | 42.0 (16.1–127) | 44.9 (13.8.–147) | 0.004 |
Exhaled NO+ ppb | 13.4 (10.0–21.5) | 13.0 (9.5–20.6) | 12 (8.3–17.3) | 0.03 |
Exhaled NO >30 ppb¶ | 61 (17.1) | 49 (14.0) | 13 (9.2) | 0.07 |