Table 2. Characteristics of the study cohort consisting of multiply exposed, singly exposed, and unexposed children (n = 1057).*.
| No exposure (N = 465) | Single exposure (N = 466) | Multiple exposures (N = 126) | P Value† | |
|---|---|---|---|---|
| Sex | § | |||
| Male | 274(59%) | 279(60%) | 64(51%) | |
| Female | 191(41%) | 187(40%) | 62(49%) | |
| Hispanic origin of father (n = 1011) | 0.14 | |||
| No | 424(96%) | 426(95%) | 112(94%) | |
| Yes | 11(2%) | 10(2%) | 0(0%) | |
| Not specified | 8(2%) | 13(3%) | 7(6%) | |
| Hispanic origin of mother | 0.33 | |||
| No | 449(97%) | 455(98%) | 125(99%) | |
| Yes | 15(3%) | 11(2%) | 1(1%) | |
| Not specified | 1(0%) | 0(0%) | 0(0%) | |
| Race of father, white (n = 1011) | 0.11 | |||
| No | 30(7%) | 25(6%) | 14(12%) | |
| Yes | 402(91%) | 410(91%) | 98(82%) | |
| Not specified | 11(2%) | 14(3%) | 7(6%) | |
| Race of mother, white | 0.09 | |||
| No | 40(9%) | 25(5%) | 14(11%) | |
| Yes | 422(91%) | 439(94%) | 112(89%) | |
| Not specified | 3(1%) | 2(0%) | 0(0%) | |
| Birth weight ≥ 2500g | 409(88%) | 422(91%) | 110(87%) | 0.30 |
| Estimated gestational age (w) | 0.45 | |||
| <32 | 18(4%) | 12(3%) | 4(3%) | |
| 32–36 | 55(12%) | 51(11%) | 13(10%) | |
| >36 | 392(84%) | 403(86%) | 109(87%) | |
| Mother's education (y) | 0.98 | |||
| <12 | 36(8%) | 44(9%) | 10(8%) | |
| 12 | 80(17%) | 83(18%) | 24(19%) | |
| 13–15 | 120(26%) | 120(26%) | 40(32%) | |
| 16 | 132(28%) | 123(26%) | 29(23%) | |
| >16 | 89(19%) | 88(19%) | 21(17%) | |
| Unknown | 8(2%) | 8(2%) | 2(2%) | |
| Father's education (y; n = 1011) | 0.86 | |||
| <12 | 14(3%) | 17(4%) | 8(7%) | |
| 12 | 97(22%) | 100(22%) | 29(24%) | |
| 13–15 | 101(23%) | 105(23%) | 25(21%) | |
| 16 | 120(27%) | 118(26%) | 24(20%) | |
| >16 | 95(21%) | 86(19%) | 23(19%) | |
| Unknown | 16(4%) | 23(5%) | 10(8%) | |
| Mother's age (y) | 29.3(5.5) | 29.2(5.7) | 28.1(5.7) | 0.56 |
| HOUSES index (n = 951) | -0.0(3.2) | 0.2(3.0) | -0.4(2.7) | 0.81 |
| Quartile of HOUSES index (n = 951) | 0.11 | |||
| 1 | 98(23%) | 103(24%) | 35(32%) | |
| 2 | 118(28%) | 90(21%) | 27(25%) | |
| 3 | 105(25%) | 105(25%) | 25(23%) | |
| 4 | 99(24%) | 123(29%) | 23(21%) |
* Values are n (%) for categorical variables and mean (SD) for continuous variables.
†P values are from Cochran-Mantel-Haenszel tests for categorical variables and generalized linear models for continuous variables taking into account the stratified design. Given the stratified design and variable number of children in each strata specific exposure group, p-values cannot be calculated directly from the data presented. When analyzing categorical variables, unknown or not specified categories are excluded from the analysis.
§Separate strata were created for males and females. Thus, each stratum was composed of a single sex.