Table 1.
Demographic and behavioral characteristics of clubfoot cases and controls, Massachusetts, New York, and North Carolina, 2006 – 2011.
| Clubfoot Cases |
Controls | |
|---|---|---|
| (n=622) | (n=2002) | |
|
|
||
| No. (%) | No. (%) | |
| Maternal race/ethnicity | ||
| White non-Hispanic | 450 (72) | 1307 (65) |
| Black non-Hispanic | 80 (13) | 334 (17) |
| Hispanic | 70 (11) | 241 (12) |
| Other/Unknown | 22 (4) | 120 (6) |
| Maternal age at conception (years) | ||
| <25 | 190 (31) | 600 (30) |
| 25–29 | 183 (29) | 558 (28) |
| 30–34 | 153 (25) | 516 (26) |
| ≥35 | 96 (15) | 328 (16) |
| Maternal education (years) | ||
| < 12 | 77 (12) | 278 (14) |
| 12 | 158 (25) | 448 (22) |
| > 12 | 387 (62) | 1276 (64) |
| Parity | ||
| Nulliparous | 304 (49) | 802 (40) |
| Multiparous | 318 (51) | 1200 (60) |
| Maternal cigarette smoking in lunar months 2 or 3 | ||
| Smoked | 164 (26) | 353 (18) |
| Did not smoke | 449 (72) | 1632 (82) |
| Missing data | 9 (1) | 17 (1) |
| Maternal alcohol use in lunar months 2 or 3 | ||
| Used alcohol | 55 (9) | 122 (6) |
| Did not use alcohol | 536 (86) | 1798 (90) |
| Missing data | 31 (5) | 82 (4) |
| Maternal body mass index (kg/m2) | ||
| < 18.5 | 21 (3) | 85 (4) |
| 18.5– < 24.9 | 289 (46) | 1062 (53) |
| 25– <30 | 168 (27) | 445 (22) |
| ≥ 29.9 | 127 (20) | 351 (18) |
| Missing data | 17 (3) | 59 (3) |
| Infant sex | ||
| Male | 452 (73) | 993 (50) |
| Female | 170 (27) | 1009 (50) |
| First degree family history of clubfoot | ||
| None | 551 (89) | 1987 (99) |
| Yes | 71 (11) | 15 (1) |
| Study center | ||
| North Carolina | 254 (41) | 990 (49) |
| New York | 199 (32) | 560 (28) |
| Massachusetts | 169 (27) | 452 (23) |