Table 1.
Differences in maternal and child characteristics in Wayne County Health, Environment, Allergy and Asthma Longitudinal Study participants with and without the 10–12 year questionnaire data, before and after inverse probability weighting (IPW)
| Covariate | Completed the 10–12-Year Questionnaire | Before IPW | After IPW | ||||
|---|---|---|---|---|---|---|---|
| No N = 613 |
Yes N = 645 |
Pa | Db | Pa | Db | ||
| Maternal Characteristic | Mean ± SD or N (%) | ||||||
| Age at delivery (years) | 28.9 ± 5.1 | 30.2 ± 5.3 | < 0.001 | 0.25 | 0.642 | 0.02 | |
| Race | White | 133 (21.7%) | 157 (24.3%) | 0.570 | 0.10 | 0.962 | 0.03 |
| Black | 387 (63.1%) | 391 (60.6%) | |||||
| Hispanic | 40 (6.5%) | 38 (5.9%) | |||||
| Arabic | 31 (5.1%) | 28 (4.3%) | |||||
| Mixed/Other | 22 (3.6%) | 31 (4.8%) | |||||
| Marital status | Unmarried | 273 (44.5%) | 212 (32.9%) | < 0.001 | 0.24 | 0.335 | 0.04 |
| Married | 340 (55.5%) | 433 (67.1%) | |||||
| Insurance coverage | HAP | 169 (27.6%) | 333 (51.6%) | < 0.001 | 0.71 | 0.815 | 0.04 |
| Other insurance | 198 (32.3%) | 233 (36.1%) | |||||
| No insurance | 9 (1.5%) | 6 (0.9%) | |||||
| Refused/do not know/missing | 237 (38.7%) | 73 (11.3%) | |||||
| Household income | <$20,000 | 112 (18.3%) | 70 (10.9%) | < 0.001 | 0.32 | 0.938 | 0.05 |
| $20,000- < $40,000 | 150 (24.5%) | 145 (22.5%) | |||||
| $40,000- < $80,000 | 173 (28.2%) | 174 (27.0%) | |||||
| $80,000- < $100,000 | 49 (8.0%) | 86 (13.3%) | |||||
| ≥$100,000 | 52 (8.5%) | 96 (14.9%) | |||||
| Refused to answer | 77 (12.6%) | 74 (11.5%) | |||||
| Education | <HS diploma | 50 (8.2%) | 24 (3.7%) | < 0.001 | 0.41 | 0.967 | 0.02 |
| HS diploma | 131 (21.4%) | 97 (15.0%) | |||||
| Some college | 313 (51.1%) | 292 (45.3%) | |||||
| ≥Bachelor’s degree | 119 (19.4%) | 232 (36.0%) | |||||
| Mother smoked during pregnancy | No | 517 (84.3%) | 591 (91.6%) | < 0.001 | − 0.23 | 0.420 | − 0.03 |
| Yes | 96 (15.7%) | 54 (8.4%) | |||||
| ETS during pregnancy | No | 421 (68.7%) | 490 (76%) | 0.004 | −0.16 | 0.666 | −0.02 |
| Yes | 192 (31.3%) | 155 (24%) | |||||
| Prenatal alcohol use | No | 590 (96.6%) | 616 (95.7%) | 0.405 | 0.05 | 0.330 | −0.04 |
| Yes | 21 (3.4%) | 28 (4.3%) | |||||
| Location of residence | Suburban | 250 (40.8%) | 305 (47.3%) | 0.020 | −0.13 | 0.224 | −0.05 |
| Urban | 363 (59.2%) | 340 (52.7%) | |||||
| Doctor-diagnosed hay fever or allergic rhinitis | No | 516 (85.0%) | 538 (84.9%) | 0.941 | 0.001 | 0.613 | 0.02 |
| Yes | 91 (15.0%) | 96 (15.1%) | |||||
| Doctor-diagnosed asthma | No | 492 (80.3%) | 513 (79.7%) | 0.790 | 0.01 | 0.584 | 0.02 |
| Yes | 121 (19.7%) | 131 (20.3%) | |||||
| Prenatal indoor dog(s) | No | 476 (77.7%) | 479 (74.3%) | 0.160 | 0.08 | 0.797 | −0.01 |
| Yes | 137 (22.3%) | 166 (25.7%) | |||||
| Prenatal indoor cat(s) | No | 520 (84.8%) | 535 (82.9%) | 0.364 | 0.05 | 0.538 | 0.02 |
| Yes | 93 (15.2%) | 110 (17.1%) | |||||
| Clinical Characteristics | |||||||
| Mode of delivery | Vaginal | 385 (63.4%) | 399 (62.1%) | 0.616 | 0.03 | 0.513 | −0.03 |
| C-section | 222 (36.6%) | 244 (37.9%) | |||||
| Firstborn | No | 401 (65.4%) | 397 (61.6%) | 0.155 | 0.08 | 0.986 | −0.001 |
| Yes | 212 (34.6%) | 248 (38.4%) | |||||
| Child sex | Male | 308 (50.3%) | 314 (48.7%) | 0.560 | 0.03 | 0.557 | 0.02 |
| Female | 304 (49.7%) | 331 (51.3%) | |||||
| Gestational age at delivery (weeks)c |
38.7 ± 1.8 (N = 595) |
38.8 ± 1.7 (N = 637) |
0.307 | 0.05 | 0.902 | 0.004 | |
| Birthweight (grams)c |
3258 ± 548 (N = 567) |
3346 ± 594 (N = 615) |
0.008 | 0.15 | 0.880 | −0.006 | |
| Completed 2-year clinic visit | No | 425 (69.3%) | 137 (21.2%) | < 0.001 | 1.10 | 0.596 | 0.02 |
| Yes | 188 (30.7%) | 508 (78.8%) | |||||
ETS environmental tobacco smoke, HAP Health Alliance Plan, HS high school, SD standard deviation
aCalculated using chi-square test for categorical covariates and analysis of variance for continuous covariates. Bold values indicate statistically significant P<0.05
bStandardized difference (difference in means or proportions divided by standard error); imbalance defined as absolute value> 0.20
cContinuous covariates with missing data, sample size is presented