Table 3.
Association between inverse distance weighted well count within 10-mile radius of maternal residence and preterm birth and term low birth weight.
| Inverse distance weighted well counta | 0 wells within 10 miles | Low (first tertile) | Medium (second tertile) | High (third tertile) | Cochran–Armitage trend test p-valueb |
|---|---|---|---|---|---|
| Preterm birth | |||||
| Live births (n) | 65,506 | 18,884 | 18,854 | 19,384 | |
| Cases (n) | 4,849 | 1,358 | 1,289 | 1,274 | |
| Crude OR | 1 | 0.97 | 0.92 | 0.88 | < 0.0001 |
| Adjusted OR (95% CI)c | 0.96 (0.89, 1.0) | 0.93 (0.87, 1.0) | 0.91 (0.85, 0.98) | ||
| Term low birth weight | |||||
| Full-term live births (n) | 60,653 | 17,525 | 17,565 | 18,104 | |
| Cases (n) | 2,287 | 525 | 471 | 432 | |
| Crude OR | 1 | 0.79 | 0.70 | 0.62 | < 0.0001 |
| Adjusted OR (95% CI)c | 1.0 (0.9, 1.1) | 0.86 (0.77, 0.95) | 0.9 (0.8, 1) | ||
| Mean difference in birth weight (g)d | 0 | 5 (–2.2, 13) | 24 (17, 31) | 22 (15, 29) | |
| aFirst tertile, 1–3.62 wells/mile; second tertile, 3.63–125 wells/mile; third tertile, 126–1,400 wells/mile. bPerformed as two-tailed test on unadjusted logistic regression.cAdjusted for maternal age, ethnicity, smoking, alcohol use, education, and elevation of residence, as well as infant parity and sex. dAdjusted for maternal age, ethnicity, smoking, alcohol use, education, and elevation of residence, as well as infant parity, sex, and gestational age. | |||||