Table 1 Characteristics of the pregnant individuals in the study population, San Joaquin Valley, California.
From: Structural birth defects and exposure to oil and gas wells during pregnancy
Characteristic | All | Cases | Controls | Active wells within 3 km | Inactive wells within 1 km | Unexposed |
|---|---|---|---|---|---|---|
n | 3631 | 2737 | 894 | 414 | 179 | 3038 |
Age at delivery, n (%) | ||||||
≤19 | 545 (15.0) | 406 (14.8) | 139 (15.5) | 59 (14.3) | 25 (14.0) | 461 (15.2) |
20–24 | 1039 (28.6) | 781 (28.5) | 258 (28.9) | 138 (33.3) | 63 (35.2) | 838 (27.6) |
25–29 | 972 (26.8) | 734 (26.8) | 238 (26.6) | 104 (25.1) | 43 (24.0) | 825 (27.2) |
30–34 | 700 (19.3) | 530 (19.4) | 170 (19.0) | 80 (19.3) | 25 (14.0) | 595 (19.6) |
≥35 | 375 (10.3) | 286 (10.4) | 89 (10.0) | 33 (8.0) | 23 (12.8) | 319 (10.5) |
Race/Ethnicity, n (%) | ||||||
Hispanic, Foreign Born | 1127 (31.0) | 864 (31.6) | 263 (29.4) | 86 (20.8) | 80 (44.7) | 961 (31.6) |
Hispanic, U.S. Born | 981 (27.0) | 744 (27.2) | 237 (26.5) | 115 (27.8) | 47 (26.3) | 819 (27.0) |
Non-Hispanic Black | 92 (2.5) | 66 (2.4) | 26 (2.9) | 20 (4.8) | 3 (1.7) | 69 (2.3) |
Non-Hispanic White | 1068 (29.4) | 785 (28.7) | 283 (31.7) | 163 (39.4) | 26 (14.5) | 879 (28.9) |
Other | 359 (9.9) | 275 (10.0) | 84 (9.4) | 29 (7.0) | 23 (12.8) | 307 (10.1) |
Missing | 4 (0.1) | 3 (0.1) | 1 (0.1) | 1 (0.2) | 0 (0) | 3 (0.1) |
Education, n (%) | ||||||
<High School | 1122 (30.9) | 863 (31.5) | 259 (29.0) | 101 (24.4) | 63 (35.2) | 958 (31.5) |
High School | 1070 (29.5) | 817 (29.9) | 253 (28.3) | 128 (30.9) | 61 (34.1) | 881 (29.0) |
>High School | 1439 (39.6) | 1057 (38.6) | 382 (42.7) | 185 (44.7) | 55 (30.7) | 1199 (39.5) |
Parity, n (%) | ||||||
Primiparous | 1365 (37.6) | 1034 (37.8) | 331 (37.0) | 143 (34.5) | 62 (34.6) | 1160 (38.2) |
1 prior birth | 1097 (30.2) | 819 (29.9) | 278 (31.1) | 142 (34.3) | 47 (26.3) | 908 (29.9) |
2 or more prior births | 1169 (32.2) | 884 (32.3) | 285 (31.9) | 129 (31.2) | 70 (39.1) | 970 (31.9) |
Folic acid intake, n (%) | ||||||
No | 1190 (32.8) | 902 (33.0) | 288 (32.2) | 123 (29.7) | 59 (33.0) | 1008 (33.2) |
Yes | 2441 (67.2) | 1835 (67.0) | 606 (67.8) | 291 (70.3) | 120 (67.0) | 2030 (66.8) |
Infant sex, n (%) | ||||||
Female | 1588 (43.7) | 1151 (42.1) | 437 (48.9) | 175 (42.3) | 78 (43.6) | 1335 (43.9) |
Male | 2028 (55.9) | 1571 (57.4) | 457 (51.1) | 236 (57.0) | 100 (55.9) | 1692 (55.7) |
Missing | 15 (0.4) | 15 (0.5) | 0 (0) | 3 (0.7) | 1 (0.6) | 11 (0.4) |
