Table 1.
Characteristics of study subjects and their respective interactions on the correlation of cord blood IgE and total IgE at age 18–21.
| Strata | n | Correlation of Cord IgE to Total IgE at age 18–21 | P-value for interaction |
|---|---|---|---|
| Gender | |||
| - Female | 296 (52%) | 0.19 | 0.82 |
| - Male | 269 (48%) | 0.17 | |
| Firstborn | |||
| - Yes | 256 (45%) | 0.18 | 0.32 |
| - No | 309 (55%) | 0.16 | |
| Mother’s age | |||
| - ≥ 30 yrs | 248 (44%) | 0.16 | 0.27* |
| - < 30 yrs | 317 (56%) | 0.19 | |
| Birth weight | |||
| - ≥ 7.4 lbs | 293 (53%) | 0.19 | 0.55* |
| - < 7.4 lbs | 259 (47%) | 0.18 | |
| Season of birth (cord blood draw) | |||
| - Winter | 101 (18%) | 0.12 | 0.74 |
| - Spring | 187 (33%) | 0.20 | |
| - Summer | 171 (30%) | 0.16 | |
| - Fall | 106 (19%) | 0.16 | |
| Season of blood draw at 18 | |||
| - Winter | 144 (25%) | 0.07 | |
| - Spring | 151 (27%) | 0.28 | 0.96 |
| - Summer | 178 (32%) | 0.14 | |
| - Fall | 92 (16%) | 0.18 | |
| Maternal history of allergy and/or asthma? | |||
| - Yes | 186 (33%) | 0.18 | 0.97 |
| - No | 379 (67%) | 0.16 | |
| Paternal history of allergy and/or asthma? | |||
| - Yes | 178 (33%) | 0.26 | 0.29 |
| - No | 364 (67%) | 0.12 | |
| Pet first year of life | |||
| - Yes | 251 (44%) | 0.11 | 0.19 |
| - No | 314 (56%) | 0.23 | |
| Household smoke exposure 1st year of life | |||
| - Yes | 183 (32%) | 0.25 | 0.20 |
| - No | 382 (68%) | 0.14 | |
| Antibiotic use 1st 6 months of life | |||
| - Yes | 268 (51%) | 0.08 | 0.014 |
| - No | 259 (49%) | 0.29 | |
| Fever 1st year of life | |||
| - Yes | 236 (44%) | 0.09 | 0.11 |
| - No | 297 (56%) | 0.23 | |
| Breastfed | |||
| - Yes | 336 (67%) | 0.18 | 0.84 |
| - No | 166 (33%) | 0.13 | |
| Daycare | |||
| - Yes | 215 (45%) | 0.11 | 0.16 |
| - No | 264 (55%) | 0.24 |
*
Interaction term was tested using mother’s age and birth weight as continuous variables.
These indices are dichotomized in this table for descriptive purposes.