TABLE 1.
Descriptive Characteristics of Mothers of Case and Control Infants, National Birth Defects Prevention Study, 1997 to 2009
| Percenta | ||
|---|---|---|
| Cases (n = 20,250) | Controls (n = 8,617) | |
| Race-ethnicity | ||
| Non-Hispanic white | 63 | 62 |
| Black | 9 | 11 |
| Hispanic | 21 | 20 |
| Other | 7 | 7 |
| Education | ||
| Less than high school | 14 | 14 |
| Equal to high school | 25 | 24 |
| Greater than high school | 60 | 62 |
| Parity | ||
| 0 | 43 | 40 |
| ≥ 1 | 57 | 60 |
| Smokingb | ||
| None | 80 | 82 |
| Any | 20 | 18 |
| Alcohol consumptionb | ||
| None | 62 | 62 |
| Any | 38 | 38 |
| Folic acid-containing vitamin/mineral supplement useb | ||
| None | 21 | 21 |
| Any | 79 | 79 |
| Pre-pregnancy body mass index (kg/m2) | ||
| Normal weight (18.5–24.9) | 55 | 57 |
| Overweight (25.0–29.9) | 25 | 24 |
| Obesity (≥30.0) | 20 | 19 |
| Diet quality indexc | ||
| Low (score 0–8) | 33 | 29 |
| Not low (score 9–24) | 67 | 71 |
| Body mass index and diet quality index combinedc | ||
| Normal weight, not low diet quality | 38 | 41 |
| Normal weight, low diet quality | 17 | 17 |
| Overweight, not low diet quality | 16 | 17 |
| Overweight, low diet quality | 8 | 7 |
| Obese, not low diet quality | 13 | 13 |
| Obese, low diet quality | 7 | 6 |
| Mean (SD) | ||
| Maternal age at delivery (years) | 27.92 (6.18) | 27.88 (6.02) |
| Energy intake (kcals) | 1565.4 (682.41) | 1595.59 (673.83) |
a
Numbers may not add to 100% due to rounding.
b
From 1 month before through 2 months after conception.
c
Diet quality defined as “low” if the score was in the lowest quartile, based on the distribution among the controls, and as “not low” otherwise.
SD, standard deviation.