TABLE 1.
Cohort characteristicsa
| Variable | Overall CHILD | CHILD study 5y | P valueb | ITS-2 | P valuec |
|---|---|---|---|---|---|
| No. of patients | 3,264 | 2,539 | 308 | ||
| Institution, no. (%) | <0.001 | <0.001 | |||
| Edmonton | 769 (23.6) | 544 (21.4) | 32 (10.4) | ||
| Toronto | 770 (23.6) | 519 (20.4) | 77 (25) | ||
| Vancouver | 730 (22.4) | 601 (23.7) | 87 (28.2) | ||
| Winnipeg | 995 (30.5) | 875 (34.5) | 112 (36.4) | ||
| Asthma at yr 5, no. (%) | <0.001 | 0.0022 | |||
| Asthma | 164 (5) | 160 (6.3) | 33 (10.7) | ||
| No asthma | 2,235 (68.5) | 2,138 (84.2) | 239 (77.6) | ||
| No phenotype available | 620 (19) | 5 (0.2) | 3 (1) | ||
| Possible asthma | 245 (7.5) | 236 (9.3) | 33 (10.7) | ||
| Inhalant atopy at yr 5, no. (%) | , | <0.001 | 0.0013 | ||
| Inhalant atopy (ever) | 438 (13.4) | 438 (17.3) | 77 (25) | ||
| No inhalant atopy | 2,101 (64.4) | 2,101 (82.7) | 231 (75) | ||
| Antibiotic use by age 3 mo, no. (%) | 0.89 | 0.87 | |||
| 586 (18) | 452 (17.8) | 53 (17.2) | |||
| Antibiotic use by age 1 yr, no. (%) | 0.065 | 0.75 | |||
| 520 (15.9) | 451 (17.8) | 57 (18.5) | |||
| Antifungal use by 3 mo, no. (%) | 0.76 | 1 | |||
| Confirmed | 24 (0.7) | 24 (0.9) | 24 (7.8) | ||
| Unknown | 2,921 (89.5) | 2,231 (87.9) | |||
| Antifungal use by age 1 yr, no. (%) | 0.77 | 1 | |||
| Confirmed | 26 (0.8) | 26 (1) | 26 (8.4) | ||
| Unknown | 2,921 (89.5) | 2,231 (87.9) | |||
| Gestational age at delivery (wks) | 0.67 | 0.47 | |||
| Median (range) | 39.7 (34, 42.9) | 39.7 (34, 42.9) | 39.9 (34.4, 42.7) | ||
| IQR (Q1, Q3) | 38.9, 40.4 | 38.9, 40.6 | 38.9, 40.6 | ||
| Unknown, no. (%) | 154 (4.7) | 127 (5) | 14 (4.5) | ||
| Mode of delivery, no. (%) | 0.95 | 0.76 | |||
| Vaginal | 2,408 (73.8) | 1,879 (74) | 228 (74) | ||
| C-section with labor | 425 (13) | 324 (12.8) | 42 (13.6) | ||
| C-section without labor | 390 (11.9) | 306 (12.1) | 33 (10.7) | ||
| Unknown | 41 (1.3) | 30 (1.2) | 5 (1.6) | ||
| Having older sibling, no. (%) | 0.98 | 0.14 | |||
| Confirmed | 1,548 (47.4) | 1,206 (47.5) | 132 (42.9) | ||
| Unknown | 59 (1.8) | 45 (1.8) | 7 (2.3) | ||
| Male, no. (%) | 0.67 | 0.28 | |||
| 1,715 (52.5) | 1,350 (53.2) | 174 (56.5) | |||
| Birth wt Z score | 0.64 | 0.49 | |||
| Median (range) | −0.1 (−5.9, 15.9) | −0.1 (−5.9, 15.8) | 0 (−2.2, 15.1) | ||
| IQR (Q1, Q3) | −0.7, 0.6 | −0.7, 0.6 | −0.6, 0.6 | ||
| Unknown | 154 (4.7) | 127 (5) | 14 (4.5) | ||
| Parental atopy, no. (%) | 0.81 | 0.31 | |||
| Confirmed | 2,447 (75) | 1,997 (78.7) | 251 (81.5) | ||
| Unknown | 246 (7.5) | 68 (2.7) | 7 (2.3) | ||
| Duration of exclusive breastfeeding (mo) | 0.32 | 0.56 | |||
| Median (range) | 4 (0, 9) | 4 (0, 9) | 4.5 (0, 6) | ||
| IQR (Q1, Q3) | 0.5, 5 | 0.5, 5 | 0.6, 5 | ||
| Unknown | 209 (6.4) | 62 (2.4) | 1 (0.3) | ||
| Tobacco smoke exposure to age 1 yr, no. (%) | 0.044 | 0.13 | |||
| Confirmed | 808 (24.8) | 610 (24) | 64 (20.8) | ||
| Unknown | 530 (16.2) | 276 (10.9) | 25 (8.1) | ||
| Season of birth, no. (%) | 0.85 | 0.62 | |||
| Spring | 889 (27.2) | 711 (28) | 93 (30.2) | ||
| Summer | 829 (25.4) | 624 (24.6) | 80 (26) | ||
| Fall | 754 (23.1) | 581 (22.9) | 69 (22.4) | ||
| Winter | 788 (24.1) | 621 (24.5) | 66 (21.4) | ||
| Unknown | 4 (0.1) | 2 (0.1) | |||
| Area type, no. (%) | 1 | 0.54 | |||
| Rural | 83 (2.5) | 74 (2.9) | 22 (7.1) | ||
| Urban | 870 (26.7) | 775 (30.5) | 272 (88.3) | ||
| Unknown | 2,311 (70.8) | 1,690 (66.6) | 14 (4.5) | ||
| Breastfeeding status at 3 mo, no. (%) | 0.61 | 0.28 | |||
| None | 446 (13.7) | 334 (13.2) | 31 (10.1) | ||
| Partial | 821 (25.2) | 657 (25.9) | 85 (27.6) | ||
| Exclusive | 1,884 (57.7) | 1,528 (60.2) | 192 (62.3) | ||
| Unknown | 113 (3.5) | 20 (0.8) | |||
| Breastfeeding status at 12 mo, no. (%) | , | 0.23 | 0.81 | ||
| Confirmed | 1358 (41.6) | 1,164 (45.8) | 141 (45.8) | ||
| Unknown | 311 (9.5) | 97 (3.8) | 7 (2.3) | ||
| Solid food by age 3 mo, no. (%) | 0.22 | 0.91 | |||
| Confirmed | 243 (7.4) | 173 (6.8) | 22 (7.1) | ||
| Unknown | 261 (8) | 126 (5) | 9 (2.9) | ||
| Presence of mold in home, no. (%) | 0.66 | 0.24 | |||
| Confirmed | 1,238 (37.9) | 979 (38.6) | 130 (42.2) | ||
| Unknown | 21 (0.6) | 13 (0.5) | |||
| Oral thrush by age 1 yr, no. (%) | 1 | 0.57 | |||
| Confirmed | 34 (1) | 29 (1.1) | 2 (0.6) | ||
| Unknown | 675 (20.7) | 345 (13.6) | 23 (7.5) | ||
| Ethnicity of child, no. (%) | 0.89 | 0.042 | |||
| Caucasian | 2,046 (62.7) | 1,628 (64.1) | 187 (60.7) | ||
| East Asian | 102 (3.1) | 80 (3.2) | 16 (5.2) | ||
| Multiracial | 745 (22.8) | 582 (22.9) | 72 (23.4) | ||
| South Asian | 78 (2.4) | 58 (2.3) | 4 (1.3) | ||
| Southeast Asian | 82 (2.5) | 66 (2.6) | 16 (5.2) | ||
| Other | 140 (4.3) | 94 (3.7) | 11 (3.6) | ||
| Unknown | 71 (2.2) | 31 (1.2) | 2 (0.6) |
a
Overall CHILD, all CHILD Cohort Study participants; CHILD Study 5y, the subset of subjects for which inhalant atopy status at age 5 years is known; ITS-2, the subset of subjects with processed stool ITS-2 rRNA gene sequencing data; IQR, interquartile range.
b
P values represent comparison between left and middle columns.
c
P values represent comparison between middle and right columns. Wilcoxon rank sum test and Fisher’s exact test were used for continuous and categorical variables, respectively.