eTable 2.
Comparison of Characteristics of Participants Included and Excluded in the Study
| Risk factors | Analysis 1 |
Analysis 2 |
||||
|---|---|---|---|---|---|---|
| Included (n = 974) | Excluded (n = 263) | P | Included (n = 431) | Excluded (n = 806) | P | |
| Prenatal factors, n (%) | ||||||
| Sex | .45 | .73 | ||||
| Female | 464 (47.6) | 88 (44.7) | 206 (47.8) | 346 (46.8) | ||
| Male | 510 (52.4) | 109 (55.3) | 225 (52.2) | 394 (53.2) | ||
| Ethnicity | .03 | .001 | ||||
| Chinese | 557 (57.3) | 134 (51.0) | 270 (62.7) | 421 (52.3) | ||
| Indian | 179 (18.4) | 44 (16.7) | 59 (13.7) | 164 (20.4) | ||
| Malay | 237 (24.4) | 85 (32.3) | 102 (23.7) | 220 (27.3) | ||
| Maternal education level | .001 | .007 | ||||
| Less than college | 281 (29.1) | 101 (39.6) | 114 (26.5) | 268 (34.0) | ||
| College and higher | 684 (70.9) | 154 (60.4) | 317 (73.6) | 521 (66.0) | ||
| Family history of allergy | 479 (54.6) | 46 (54.8) | .97 | 245 (56.8) | 280 (52.7) | .20 |
| Parity | .07 | .31 | ||||
| 0 | 438 (45.0) | 98 (49.5) | 185 (42.9) | 351 (47.4) | ||
| 1 | 327 (33.6) | 72 (36.4) | 152 (35.3) | 247 (33.3) | ||
| ≥ 2 | 209 (21.5) | 28 (14.1) | 94 (21.8) | 143 (19.3) | ||
| Cesarean section | 298 (30.6) | 52 (26.3) | .22 | 121 (28.1) | 229 (31.0) | .30 |
| Birth weight (kg), mean (SD) | 3.10 (0.44) | 2.97 (0.55) | .001 | 3.11 (0.44) | 3.06 (0.48) | .07 |
| Tobacco exposure during pregnancy | 339 (36.5) | 98 (49.0) | .001 | 151 (35.0) | 286 (41.0) | .047 |
| Environmental factors, n (%) | ||||||
| Cat ownership by 1 y | 32 (4.0) | 0 (0.0) | .40 | 22 (5.1) | 10 (2.5) | .046 |
| Dog ownership by 1 y | 60 (7.6) | 3 (6.8) | >.99 | 31 (7.2) | 32 (7.9) | .71 |
| Childcare attendance by 1 y | 72 (13.0) | 4 (23.5) | .26 | 61 (14.2) | 15 (10.8) | .31 |
| Type of feeding | <.001 | .002 | ||||
| Mainly breastfeeding | 119 (12.7) | 3 (3.3) | 68 (15.8) | 54 (9.0) | ||
| Mixed feeding | 424 (45.2) | 22 (24.4) | 188 (43.6) | 258 (43.1) | ||
| Mainly formula | 396 (42.2) | 65 (72.2) | 175 (40.6) | 286 (47.8) | ||
| Eczema in early life by 6 mo | 74 (8.6) | 10 (19.6) | .008 | 43 (10.0) | 41 (8.4) | .42 |
| Rhinitis in early life by 6 mo | 233 (26.8) | 23 (32.4) | .31 | 104 (24.1) | 152 (29.8) | .051 |
| Respiratory infections by 6 mo | 51 (5.6) | 3 (4.4) | >.99 | 24 (5.6) | 30 (5.5) | .97 |
NOTE. Analysis 1 is a group-based trajectory model that was used to derive wheeze trajectories. Analysis 2 is a multivariable multinomial logistic regression model, which assessed the association between predictive risk factors and wheeze trajectory.