Table 1.
Distribution of Selected Characteristics of Children With Severe Hypospadias and Nonmalformed Control Children in the National Birth Defects Prevention Study, 1997–2009
| Characteristic | Children in the Case Group (n=2,131) |
Children in the Control Group (n=5,129) |
P |
|---|---|---|---|
| Maternal age (y) | <.001 | ||
| Younger than 20 | 144 (6.8) | 551 (10.7) | |
| 20–34 | 1,556 (73.0) | 3,877 (75.6) | |
| 35 or older | 431 (20.2) | 701 (13.7) | |
| Maternal race or ethnicity | <.001 | ||
| Non-Hispanic white | 1,531 (71.8) | 2,942 (57.4) | |
| Non-Hispanic black | 271 (12.7) | 565 (11.0) | |
| Hispanic | 182 (8.5) | 1,230 (24.0) | |
| Other | 144 (6.8) | 384 (7.5) | |
| Missing | 3 (0.1) | 8 (0.2) | |
| Maternal education | <.001 | ||
| Less than high school | 163 (7.7) | 867 (16.9) | |
| High school | 416 (19.5) | 1,236 (24.1) | |
| Some college | 570 (26.8) | 1,341 (26.2) | |
| College degree | 937 (44.0) | 1,570 (30.6) | |
| Missing | 45 (2.1) | 115 (2.2) | |
| Maternal prepregnancy BMI (kg/m2) | .387 | ||
| Underweight | 100 (4.7) | 279 (5.4) | |
| Normal weight | 1,121 (52.6) | 2,643 (51.5) | |
| Overweight | 480 (22.5) | 1,118 (21.8) | |
| Obese | 386 (18.1) | 858 (16.7) | |
| Missing | 44 (2.1) | 231 (4.5) | |
| Parity | <.001 | ||
| 0 | 1,144 (53.7) | 2,053 (40.0) | |
| 1 | 622 (29.2) | 1,672 (32.6) | |
| 2 or more | 357 (16.8) | 1,395 (27.2) | |
| Missing | 8 (0.4) | 9 (0.2) | |
| Maternal fertility treatment | <.001 | ||
| Yes | 214 (10.0) | 204 (4.0) | |
| No | 1,917 (90.0) | 4,925 (96.0) | |
| Oral contraceptive use | .166 | ||
| Yes | 252 (11.9) | 669 (13.1) | |
| No | 1,869 (88.1) | 4,448 (86.9) | |
| Periconceptional folic acid use | <.001 | ||
| Yes | 1,355 (63.6) | 2,644 (51.6) | |
| No | 738 (34.6) | 2,372 (46.3) | |
| Missing | 38 (1.8) | 113 (2.2) | |
| Prepregnancy diabetes | .001 | ||
| Yes | 28 (1.3) | 29 (0.6) | |
| No | 2,102 (98.6) | 5,094 (99.3) | |
| Missing | 1 (<0.1) | 6 (0.1) | |
| Gestational diabetes | .116 | ||
| Yes | 114 (5.4) | 230 (4.5) | |
| No | 2,016 (94.6) | 4,893 (95.4) | |
| Missing | 1 (<0.1) | 6 (0.1) | |
| Early pregnancy nausea or vomiting | <.001 | ||
| Yes | 1,319 (61.9) | 3,467 (67.6) | |
| No | 802 (37.6) | 1,640 (32.0) | |
| Missing | 10 (0.5) | 22 (0.4) | |
| Early pregnancy alcohol use | <.001 | ||
| Yes | 876 (41.1) | 1,860 (36.3) | |
| No | 1,197 (56.2) | 3,144 (61.3) | |
| Missing | 58 (2.7) | 125 (2.4) | |
| Early pregnancy smoking | .074 | ||
| Yes | 353 (16.6) | 941 (18.4) | |
| No | 1,734 (81.4) | 4,089 (79.7) | |
| Missing | 44 (2.1) | 99 (1.9) | |
| Multiple birth | <.001 | ||
| Yes | 174 (8.2) | 144 (2.8) | |
| No | 1,957 (91.8) | 4,958 (97.2) | |
| Preterm birth (less than 37 wk of gestation) | <.001 | ||
| Yes | 561 (26.3) | 484 (9.4) | |
| No | 1,568 (73.6) | 4,645 (90.6) | |
| Missing | 2 (0.1) | 0 (0.0) | |
| Low birth weight (less than 2,500 g) | <.001 | ||
| Yes | 556 (26.1) | 286 (5.6) | |
| No | 1,544 (72.5) | 4,773 (93.1) | |
| Missing | 31 (1.5) | 70 (1.4) | |
| Family history (1st-degree relative) | <.001 | ||
| Yes | 97 (4.6) | 10 (0.2) | |
| No | 2,034 (95.5) | 5,119 (99.8) |
BMI, body mass index.