Table 1:
Comparison of black and white children included and excluded from analysis, before and after inverse probability weighting (IPW) to account for loss to follow-up.
| Covariate | Level | Included in Analysis1 | Before IPW | After IPW | |||
|---|---|---|---|---|---|---|---|
| No N=572 | Yes N=481 | Standardized Difference2 | p-value3 | Standardized Difference2 | p-value3 | ||
| N (Col %) or N, Mean±SD | |||||||
| Household Income | <$20K | 94 (16.4) | 51 (10.6) | 0.28 | <0.05 | 0.04 | 0.980 |
| 20-<$40K | 141 (24.7) | 109 (22.7) | |||||
| 40K-<$80K | 155 (27.1) | 129 (26.8) | |||||
| $80K-<$100K | 47 (8.2) | 67 (13.9) | |||||
| ≥$100K | 56 (9.8) | 70 (14.6) | |||||
| Refused to Answer | 79 (13.8) | 55 (11.4) | |||||
| Maternal Education | <HS diploma | 47 (8.2) | 15 (3.1) | 0.43 | <0.05 | 0.01 | 0.999 |
| HS diploma | 125 (21.9) | 72 (15) | |||||
| Some college | 295 (51.6) | 227 (47.2) | |||||
| ≥Bachelor’s Degree | 105 (18.4) | 167 (34.7) | |||||
| Maternal Marital Status | Unmarried | 265 (46.3) | 182 (37.8) | 0.17 | <0.05 | 0.01 | 0.78 |
| Married | 307 (53.7) | 299 (62.2) | |||||
| Insurance Coverage | HAP | 180 (31.5) | 251 (52.2) | 0.68 | <0.05 | 0.03 | 0.95 |
| Other insurance | 169 (29.5) | 175 (36.4) | |||||
| No insurance | 8 (1.4) | 2 (0.4) | |||||
| Refused/Don’t Know/Missing | 215 (37.6) | 53 (11) | |||||
| Location of Residence | Suburban | 218 (38.1) | 209 (43.5) | −0.11 | 0.08 | −0.01 | 0.78 |
| Urban | 354 (61.9) | 272 (56.5) | |||||
| Prenatal Alcohol Use | No | 553 (97) | 457 (95.2) | 0.09 | 0.13 | −0.02 | 0.62 |
| Yes | 17 (3) | 23 (4.8) | |||||
| Prenatal Environmental Tobacco Smoke (ETS) Exposure | No | 386 (67.5) | 361 (75.1) | −0.17 | 0.01 | −0.01 | 0.77 |
| Yes | 186 (32.5) | 120 (24.9) | |||||
| Prenatal Indoor Dog(s) | No | 437 (76.4) | 354 (73.6) | 0.06 | 0.30 | −0.01 | 0.81 |
| Yes | 135 (23.6) | 127 (26.4) | |||||
| Prenatal Indoor Cat(s) | No | 478 (83.6) | 399 (83) | 0.02 | 0.79 | 0.03 | 0.56 |
| Yes | 94 (16.4) | 82 (17) | |||||
| Parental History of Doctor-Diagnosed Allergies | No | 368 (73.3) | 304 (74.1) | 0.08 | 0.78 | 0.02 | 0.94 |
| Yes | 134 (26.7) | 106 (25.9) | |||||
| Mode of Delivery | Vaginal | 358 (62.9) | 301 (62.7) | 0.01 | 0.94 | 0.01 | 0.91 |
| C-Section | 211 (37.1) | 179 (37.3) | |||||
| Season of Birth | Winter | 116 (20.3) | 103 (21.4) | ||||
| Spring | 130 (22.7) | 105 (21.8) | 0.04 | 0.92 | 0.001 | 1.000 | |
| Summer | 150 (26.2) | 131 (27.2) | |||||
| Fall | 176 (30.8) | 142 (29.5) | |||||
| Child Sex | Male | 280 (49) | 239 (49.7) | −0.01 | 0.83 | 0.03 | 0.42 |
| Female | 291 (51) | 242 (50.3) | |||||
| Child Race | White | 149 (26) | 118 (24.5) | 0.03 | 0.57 | −0.003 | 0.95 |
| Black | 423 (74) | 363 (75.5) | |||||
| Maternal Age at Birth | 572, 29.0±5.2 | 481, 30.3±5.3 | 0.24 | <0.05 | −0.004 | 0.93 | |
| Gestational Age (weeks) | 557, 38.7±1.9 | 474, 38.8±1.7 | 0.05 | 0.38 | −0.0003 | 0.99 | |
| Birthweight z-score | 532, − 0.2±0.9 | 456, −0.1±1.0 | 0.15 | <0.05 | 0.01 | 0.88 | |
| Number of Older Siblings | 572, 1.2±1.3 | 481, 1.0±1.2 | −0.14 | <0.05 | −0.02 | 0.66 | |
1
Among the 1,053 black or white children in the WHEALS cohort.
2
Difference in means or proportions divided by standard error; imbalance defined as absolute value greater than 0.20.
3
Calculated by ANOVA for numerical covariates and the chi-square test for categorical covariates.