Table 1. Description of the Study Cohort by Maternal Race/Ethnicitya.
| Variable | White (n = 606) | Black (n = 589) | Hispanic (n = 635) | Asian (n = 454) | P Valueb |
|---|---|---|---|---|---|
| At enrollment, mean (SD) | |||||
| Gestational age, wk | 12.5 (1.0) | 12.5 (1.1) | 12.9 (0.8) | 12.9 (0.8) | <.001 |
| Maternal age, y | 30.3 (4.4) | 25.5 (5.5) | 27.1 (5.5) | 30.5 (4.5) | <.001 |
| Prepregnancy BMI, mean (SD) | 23.2 (2.8) | 24.1 (3.2) | 24.4 (2.9) | 22.3 (2.7) | <.001 |
| Maternal levels at enrollment, mean (SD), ng/mL | |||||
| Plasma cotinine | 1.0 (12.6) | 3.7 (25.5) | 0.3 (4.2) | 0.04 (0.2) | <.001 |
| Total plasma lipids | 611.6 (97.2) | 578.5 (99.3) | 628.2 (93.5) | 619.6 (93.7) | <.001 |
| Gestational age at delivery, mean (SD), wk | 39.3 (1.5) | 39.0 (2.0) | 39.3 (1.7) | 39.3 (1.3) | .003 |
| Educational level | |||||
| <High school | 5 (1) | 64 (11) | 152 (24) | 27 (6) | <.001 |
| High school diploma or GED or equivalent | 29 (5) | 165 (28) | 151 (24) | 49 (11) | |
| Some college or associate’s degree | 112 (18) | 225 (38) | 234 (37) | 93 (20) | |
| Bachelor’s degree | 249 (41) | 87 (15) | 75 (12) | 145 (32) | |
| Master’s degree or advanced degree | 211 (35) | 48 (8) | 23 (4) | 140 (31) | |
| Parity: live births and stillbirths >20 wk | |||||
| 0 | 337 (56) | 295 (50) | 249 (39) | 247 (54) | <.001 |
| 1 | 196 (32) | 178 (30) | 232 (37) | 168 (37) | |
| 2 | 59 (10) | 88 (15) | 95 (15) | 32 (7) | |
| ≥3 | 14 (2) | 28 (5) | 59 (9) | 7 (2) | |
| Marital status | |||||
| Not married | 38 (6) | 301 (51) | 168 (26) | 40 (9) | <.001 |
| Married or living as married | 568 (94) | 288 (49) | 467 (74) | 414 (91) | |
| Infant sex | |||||
| Male | 333 (55) | 295 (50) | 334 (53) | 225 (50) | .25 |
| Female | 273 (45) | 294 (50) | 301 (47) | 229 (50) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); GED, General Education Development.
SI conversion factors: To convert plasma cotinine level from ng/mL or μg/L to nmol/L, multiply by 5.675.
a
Missing data have been imputed. Values given as number (percentage) unless otherwise indicated.
b
P values derived from analysis of variance or χ2 test comparing 4 groups.