Table II.
Unadjusted and adjusted associations of BA with epidemiological factors relevant to fetal development
| Characteristic | Live Births (N=4,689,920) | Cases (N=305) | PR (95%CI) | |
|---|---|---|---|---|
| Unadjusted | Adjusted | |||
| Infant factors | ||||
| Sex | ||||
| Male | 2,398,625 | 117 | 1.00 (Ref) | 1.00 (Ref) |
| Female | 2,291,295 | 188 | 1.68 (1.34–2.12) | 1.68 (1.33–2.12) |
| Gestational Age | ||||
| 37 weeks | 4,166,862 | 244 | 1.00 (Ref) | 1.00 (Ref) |
| 32 to 37 weeks | 413,469 | 41 | 1.69 (1.22–2.36) | 1.64 (1.18–2.29) |
| 32 weeks | 77,644 | 18 | 3.96 (2.45–6.39) | 3.85 (2.38–6.22) |
| Season of Conception | ||||
| Spring | 1,168,576 | 93 | 1.00 (Ref) | 1.00 (Ref) |
| Summer | 1,123,261 | 70 | 0.78 (0.57–1.07) | 0.79 (0.58–1.08) |
| Fall | 1,177,803 | 58 | 0.62 (0.45–0.86) | 0.62 (0.45–0.86) |
| Winter | 1,207,419 | 82 | 0.85 (0.63–1.15) | 0.86 (0.64–1.15) |
| Plurality | ||||
| Singleton | 4,550,904 | 293 | 1.00 (Ref) | – |
| Multiple | 138,805 | 12 | 1.34 (0.75–2.39) | |
| Maternal Factors | ||||
| Race/ethnicity | ||||
| NH White | 1,722,437 | 66 | 1.00 (Ref) | 1.00 (Ref) |
| NH Black | 449,082 | 25 | 1.45 (0.92–2.30) | 1.54 (1.06–2.24) |
| Hispanic | 2,334,327 | 108 | 1.21 (0.89–1.64) | 1.22 (0.94–1.59) |
| Other | 178,551 | 13 | 1.90 (1.05–3.44) | 1.94 (1.19–3.19) |
| Age | ||||
| <20 years | 634,163 | 36 | 1.00 (Ref) | – |
| 20–24 years | 1,312,061 | 90 | 1.21 (0.82–1.78) | |
| 25–29 years | 1,271,536 | 83 | 1.15 (0.78–1.70) | |
| 30–34 years | 952,013 | 58 | 1.07 (0.71–1.63) | |
| 35–39 years | 428,106 | 31 | 1.28 (0.79–2.06) | |
| ≥ 40 years | 91,626 | 7 | 1.35 (0.60–3.02) | |
| Previous pregnancies that resulted in live births | ||||
| 0 | 1,784,835 | 102 | 1.00 (Ref) | – |
| 1 | 1,432,004 | 94 | 1.15 (0.87–1.52) | |
| 2+ | 1,392,835 | 103 | 1.29 (0.98–1.70) | |
| Previous pregnancies that did not result in live births | ||||
| 0 | 3,678,199 | 246 | 1.00 (Ref) | – |
| 1 | 674,849 | 32 | 0.71 (0.49–1.02) | |
| 2+ | 282,472 | 23 | 1.22 (0.79–1.87) | |
| Diabetes | ||||
| No | 4,513,478 | 278 | 1.00 (Ref) | 1.00 (Ref) |
| Yes | 176,441 | 27 | 2.48 (1.67–3.69) | 2.34 (1.57–3.48) |
| Pre-gestational diabetes* | ||||
| No | 2,983,924 | 190 | 1.00 (Ref) | |
| Yes | 19,839 | 7 | 5.54 (2.61–11.78) | 4.94 (2.32–10.54) |
| Gestational diabetes* | ||||
| No | 2,891,726 | 187 | 1.00 (Ref) | |
| Yes | 112,392 | 10 | 1.38 (0.73–2.60) | 1.30 (0.69–2.46) |
| BMI* | ||||
| Underweight | 126,306 | 8 | 1.00 (Ref) | – |
| Normal | 1,450,521 | 90 | 0.98 (0.48–2.02) | |
| Overweight | 735,353 | 42 | 0.90 (0.42–1.92) | |
| Obese | 670,509 | 53 | 1.25 (0.59–2.62) | |
| Education | ||||
| <12 years | 1,290,001 | 90 | 1.00 (Ref) | — |
| 12 years | 1,378,473 | 99 | 1.03 (0.77–1.37) | |
| 12 years | 1,378,473 | 99 | 1.03 (0.77–1.37) | |
| >12 years | 1,992,755 | 113 | 0.81 (0.62–1.07) | |
| Residence near Texas/Mexico border | ||||
| Yes | 771,758 | 50 | 1.00 (Ref) | — |
| No | 3,918,161 | 255 | 1.00 (0.74–1.36) | |
| Paternal Factors | ||||
| Race/Ethnicity | ||||
| NH White | 1,509,533 | 82 | 1.00 (Ref) | – |
| NH Black | 365,479 | 33 | 1.66 (1.11–2.49) | |
| Hispanic | 1,976,540 | 124 | 1.15 (0.87–1.53) | |
| Other | 157,719 | 20 | 2.33 (1.43–3.81) | |
| Age | ||||
| <20 years | 226,886 | 17 | 1.00 (Ref) | – |
| 20–24 years | 840,910 | 48 | 0.76 (0.44–1.32) | |
| 25–29 years | 1,079,621 | 72 | 0.89 (0.52–1.51) | |
| 30–34 years | 973,270 | 60 | 0.82 (0.48–1.41) | |
| 35–39 years | 563,836 | 34 | 0.80 (0.45–1.44) | |
| ≥ 40 years | 329,460 | 28 | 1.13 (0.62–2.07) | |
| Education | ||||
| <12 years | 1,011,173 | 74 | 1.00 (Ref) | – |
| 12 years | 1,253,607 | 81 | 0.88 (0.64–1.21) | |
| >12 years | 1,710,752 | 100 | 0.80 (0.59–1.08) | |
*
Analysis limited to subset of patients born between 2005–2014.
Abbreviations: NH = non-Hispanic; PR = prevalence ratio; CI = confidence interval; Ref = reference