Table 1.
Baseline characteristics of the children of the COPSAC2000 cohort, comparing the children who had nasopharyngeal swab samples successfully obtained and sequenced with those who did not
| Characteristic | N | Sample available, N = 285a | No sample available, N = 126a | p valueb |
|---|---|---|---|---|
| Sex | 411 | 0.5 | ||
| Female | 141 (49%) | 67 (53%) | ||
| Male | 144 (51%) | 59 (47%) | ||
| Ethnicity | 411 | 0.8 | ||
| Northern European | 276 (97%) | 121 (96%) | ||
| Other | 9 (3.2%) | 5 (4.0%) | ||
| Delivery mode | 411 | 0.4 | ||
| Cesarean section | 63 (22%) | 23 (18%) | ||
| Vaginal | 222 (78%) | 103 (82%) | ||
| Gestational age (weeks) | 411 | 40.43 (39.29, 41.43) | 40.29 (39.43, 41.71) | 0.5 |
| Birth weight (kg) | 411 | 3.50 (3.20, 3.82) | 3.55 (3.20, 3.80) | 0.8 |
| Birth length (cm) | 411 | 52.00 (51.00, 54.00) | 52.00 (51.00, 54.00) | 0.9 |
| Season of birth | 411 | 0.00006 | ||
| Autumn | 64 (22%) | 55 (44%) | ||
| Spring | 70 (25%) | 16 (13%) | ||
| Summer | 85 (30%) | 26 (21%) | ||
| Winter | 66 (23%) | 29 (23%) | ||
| Living environment | 411 | 0.9 | ||
| Rural | 147 (52%) | 66 (52%) | ||
| Urban | 138 (48%) | 60 (48%) | ||
| Older siblings, any | 386 | 113 (42%) | 38 (32%) | 0.053 |
| Missing data | 18 | 7 | ||
| Furred pet at home | 389 | 78 (29%) | 37 (31%) | 0.6 |
| Missing data | 14 | 8 | ||
| Maternal smoking at 1 month | 354 | 39 (16%) | 27 (26%) | 0.027 |
| Missing data | 36 | 21 | ||
| Breastfeeding at 1 month | 367 | 210 (82%) | 93 (85%) | 0.5 |
| Missing data | 28 | 16 | ||
| Social circumstances PCA score | 382 | −0.07 (−0.70, 0.60) | −0.15 (−0.81, 0.51) | 0.3 |
| Missing data | 20 | 9 | ||
| Antibiotics during pregnancy | 411 | 83 (29%) | 42 (33%) | 0.4 |
an (%); median (interquartile range).
bPearson’s Chi-squared; Fisher’s exact test; Wilcoxon rank-sum test. P values are two-sided and not adjusted for multiple comparisons.