Table 2.
Characteristics of the cases and controls among women who gave birth
| Characteristics | Cases (n = 196) | Controls (n = 196) | p value, differencea |
|---|---|---|---|
| Age, years | |||
| Median age (IQR) | 23 (20–28) | 21 (19–23) | 0.0001 |
| Mean age (range) | 25 (17–42) | 22 (16–37) | < 0.0001 |
| Women < 30, % | 68 | 66 | 0.004 |
| Women < 35, % | 80 | 70 | 0.04 |
| Missing data on age, % | 14 | 28 | 0.0008 |
| Race/ethnicity, % | |||
| Caucasian | 61 | 52 | < 0.001 |
| Black | 11 | 26 | |
| Hispanic | 6 | 11 | |
| Asian | 2 | 3 | |
| Other | 2 | 3 | |
| Missing data on race | 16 | 6 | |
| Place of residence, % | |||
| USA | 66 | 77 | 0.04 |
| UK | 16 | 8 | |
| Canada | 4 | 3 | |
| Other | 2 | 3 | |
| Missing data on place of residence | 6 | 9 | |
IQR interquartile range
ap values were estimated using the chi-squared test