TABLE 2.
Characteristics among case and control mothers, NBDPS, 1997–20091
| Characteristics | Cases (n = 1125) | Controls (n = 9483) | Crude OR (95% CI) |
|---|---|---|---|
| Age, y | |||
| <20 | 419 (37.2) | 946 (10.0) | 6.77 (5.58, 8.20) |
| 20–24 | 460 (40.9) | 2163 (22.8) | 3.25 (2.70, 3.91) |
| 25–29 | 173 (15.4) | 2643 (27.9) | 1.0 |
| 30–34 | 59 (5.2) | 2425 (25.6) | 0.37 (0.28, 0.50) |
| ≥35 | 14 (1.2) | 1306 (13.8) | 0.16 (0.10, 0.28) |
| Race/ethnicity | |||
| White, non-Hispanic | 579 (51.5) | 5603 (59.1) | 1.0 |
| Hispanic | 349 (31.0) | 2186 (23.1) | 1.55 (1.34, 1.78) |
| Other | 197 (17.5) | 1688 (17.8) | 1.13 (0.95, 1.34) |
| Missing | 0 (0) | 6 (0.1) | — |
| Education, y | |||
| <12 | 313 (27.8) | 1570 (16.6) | 1.0 |
| 12 | 439 (39.0) | 2252 (23.7) | 0.98 (0.83, 1.15) |
| >12 | 360 (32.0) | 5611 (59.2) | 0.32 (0.27, 0.38) |
| Missing | 13 (1.2) | 50 (0.5) | — |
| Preconception BMI | |||
| <18.5 | 99 (8.8) | 498 (5.3) | 1.31 (1.04, 1.65) |
| 18.5–24.9 | 749 (66.6) | 4944 (52.1) | 1.0 |
| 25.0–29.9 | 190 (16.9) | 2088 (22.0) | 0.60 (0.51, 0.71) |
| ≥30.0 | 55 (4.9) | 1561 (16.5) | 0.23 (0.18, 0.31) |
| Missing | 32 (2.8) | 392 (4.1) | — |
| Cigarette smoking2 | |||
| No | 708 (62.9) | 7755 (81.8) | 1.0 |
| Yes | 412 (36.6) | 1714 (18.1) | 2.63 (2.31, 3.01) |
| Missing | 5 (0.4) | 14 (0.1) | — |
| Periconceptional folic acid3 | |||
| No | 186 (16.5) | 1136 (12.0) | 1.0 |
| Yes | 925 (82.2) | 8269 (87.2) | 0.68 (0.58, 0.81) |
| Missing | 14 (1.2) | 78 (0.8) | — |
| Gravidity | |||
| 0 | 554 (49.2) | 2825 (29.8) | 1.0 |
| 1 | 315 (28.0) | 2752 (29.0) | 0.58 (0.50, 0.68) |
| 2 | 124 (11.0) | 1878 (19.8) | 0.34 (0.28, 0.41) |
| ≥3 | 132 (11.7) | 2028 (21.4) | 0.33 (0.27, 0.41) |
| DQI4 | 34.1 ± 13.9 | 36.0 ± 13.6 | — |
| MDS4 | 37.2 ± 9.9 | 39.4 ± 9.9 | — |
1
Values are n (%) unless otherwise indicated. DQI, Diet Quality Index; MDS, Mediterranean diet score; NBDPS, National Birth Defects Prevention Study.
2
Smoking anytime from 1 mo before to 3 mo after conception.
3
Folic acid supplements taken from 1 mo before to 3 mo after conception, with or without a multivitamin.
4
Values are mean scores ± SDs.