Table 4.
Odds ratios (95% CIs) of preterm birth subcategories in association with ln-unit increase in BPA concentration (ng/mL).
| Preterm subcategory | Model 1a | Model 2b | Model 3c | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n (cases, controls) | OR (95% CI) | p-Value | n (cases, controls) | OR (95% CI) | p-Value | n (cases, controls) | OR (95% CI) | p-Value | |
| Placental PTB | |||||||||
| Average(visit 1–3) | 35, 352 | 1.60 (0.91, 2.83) | 0.10 | 33, 334 | 1.56 (0.75, 3.27) | 0.24 | 33, 334 | 1.42 (0.66, 3.06) | 0.37 |
| Visit 1 | 35, 351 | 1.35 (0.92, 1.98) | 0.13 | 33, 333 | 1.26 (0.77, 2.04) | 0.36 | 33, 333 | 1.17 (0.71, 1.94) | 0.54 |
| Visit 2 | 31, 304 | 1.40 (0.91, 2.18) | 0.13 | 29, 293 | 1.66 (0.93, 2.95) | 0.08 | 29, 293 | 1.66 (0.90, 3.06) | 0.10 |
| Visit 3 | 32, 301 | 1.02 (0.53, 1.55) | 0.93 | 30, 287 | 1.12 (0.66, 1.91) | 0.67 | 30, 287 | 1.06 (0.60, 1.87) | 0.83 |
| Visit 4 | 15, 314 | 1.06 (0.54, 2.10) | 0.87 | 13, 298 | 1.24 (0.53, 2.92) | 0.62 | 13, 298 | 1.11 (0.45, 2.75) | 0.81 |
| Combined model (visit 1–3)d | 29, 263 | 27, 254 | 27, 254 | ||||||
| Visit 1 | 1.12 (0.68, 1.86) | 0.65 | 0.99 (0.50, 1.94) | 0.97 | 0.98 (0.50, 1.93) | 0.96 | |||
| Visit 2 | 1.45 (0.88, 2.37) | 0.14 | 2.00 (1.00, 4.00) | 0.05 | 1.93 (0.94, 3.94) | 0.07 | |||
| Visit 3 | 0.90 (0.57, 1.42) | 0.66 | 0.80 (0.43, 1.49) | 0.48 | 0.77 (0.40, 1.48) | 0.44 | |||
| Spontaneous PTB | |||||||||
| Average(visit 1–3) | 56, 352 | 1.42 (0.88, 2.29) | 0.15 | 56, 334 | 1.32 (0.77, 2.26) | 0.31 | 56, 334 | 1.19 (0.68, 2.06) | 0.55 |
| Visit 1 | 56, 351 | 1.15 (0.83, 1.59) | 0.40 | 56, 333 | 1.06 (0.75, 1.50) | 0.74 | 56, 333 | 1.01 (0.71, 1.44) | 0.96 |
| Visit 2 | 52, 304 | 1.18 (0.82, 1.70) | 0.36 | 52, 293 | 1.19 (0.80, 1.77) | 0.39 | 52, 293 | 1.20 (0.80, 1.80) | 0.38 |
| Visit 3 | 47, 301 | 0.90 (0.63, 1.30) | 0.58 | 47, 287 | 0.79 (0.54, 1.18) | 0.25 | 47, 287 | 0.68 (0.44, 1.05) | 0.08 |
| Visit 4 | 25, 314 | 1.86 (1.18, 2.94) | 0.01 | 25, 298 | 2.46 (1.42, 4.25) | 0.001 | 25, 298 | 2.25 (1.28, 4.00) | 0.005 |
| Combined model (visit 1–3)d | 44, 254 | 44, 254 | 44, 254 | ||||||
| Visit 1 | 1.13 (0.75, 1.71) | 0.55 | 1.09 (0.71, 1.70) | 0.69 | 1.08 (0.69, 1.68) | 0.75 | |||
| Visit 2 | 1.17 (0.77, 1.78) | 0.46 | 1.27 (0.81, 2.00) | 0.30 | 1.24 (0.79, 1.96) | 0.35 | |||
| Visit 3 | 0.90 (0.62, 1.32) | 0.59 | 0.82 (0.55, 1.22) | 0.33 | 0.78 (0.51, 1.18) | 0.23 | |||
| Placental PTB includes preterm births arising from preeclampsia or intrauterine growth restriction. Spontaneous PTB includes preterm births arising from preterm labor, premature rupture of membranes, or cervical insufficiency.aAdjusted for specific gravity. bModel adjusted for specific gravity, maternal age, race, maternal educational level attained, medical insurance, parity, prior history of PTB, and BMI. cAdditional adjustment for geometric average sum of DEHP metabolites. dCombined model adjusted for all three study visits simultaneously. | |||||||||