Table 2.
Odds ratios (95% confidence intervals) for preterm birth, spontaneous preterm birth, non-spontaneous preterm birth, and preterm birth subtypes in association with an interquartile range increase in averaged concentrations of urinary specific gravity–corrected oxidative stress biomarkers (ng/mL) within the overall sample and in a meta-analysis of cohort-specific estimates.
| Unadjusted | Adjusted | Meta-analysis | ||||||
|---|---|---|---|---|---|---|---|---|
| N (PTB, FTB) |
OR | (95% CI) | N (PTB, FTB) |
OR | (95% CI) | OR | (95% CI) | |
| All preterm births | ||||||||
| Measured | ||||||||
| 8-iso-PGF2α | (208, 1708) | 1.32 | (1.07, 1.64) | (190, 1623) | 1.19 | (0.94, 1.5) | 1.16 | (0.92, 1.40) |
| F2-IsoP-M | (208, 1708) | 1.25 | (1.10, 1.44) | (190, 1623) | 1.29 | (1.11, 1.51) | 1.22 | (1.07, 1.37) |
| PGF2α | (208, 1708) | 1.13 | (0.95, 1.35) | (190, 1623) | 1.04 | (0.86, 1.25) | 1.06 | (0.88, 1.25) |
| Derived | ||||||||
| 8-iso-PGF2α chemical | (208, 1708) | 1.22 | (0.98, 1.51) | (190, 1623) | 1.11 | (0.88, 1.41) | 1.08 | (0.84, 1.32) |
| 8-iso-PGF2α enzymatic | (208, 1708) | 1.02 | (0.86, 1.20) | (190, 1623) | 0.98 | (0.83, 1.16) | 1.00 | (0.82, 1.18) |
| Spontaneous preterm birth | ||||||||
| Measured | ||||||||
| 8-iso-PGF2α | (112, 1708) | 1.21 | (0.91, 1.61) | (99, 1623) | 1.17 | (0.86, 1.61) | 1.13 | (0.80, 1.45) |
| F2-IsoP-M | (112, 1708) | 1.24 | (1.03, 1.51) | (99, 1623) | 1.47 | (1.16, 1.90) | 1.38 | (1.14, 1.63) |
| PGF2α | (112, 1708) | 1.19 | (0.94, 1.51) | (99, 1623) | 1.13 | (0.88, 1.45) | 1.12 | (0.86, 1.38) |
| Derived | ||||||||
| 8-iso-PGF2α chemical | (112, 1708) | 1.04 | (0.79, 1.38) | (99, 1623) | 1.02 | (0.75, 1.40) | 0.98 | (0.67, 1.29) |
| 8-iso-PGF2α enzymatic | (112, 1708) | 1.14 | (0.91, 1.46) | (99, 1623) | 1.13 | (0.89, 1.46) | 1.13 | (0.88, 1.39) |
| Non-spontaneous preterm birth | ||||||||
| Measured | ||||||||
| 8-iso-PGF2α | (96, 1708) | 1.48 | (1.09, 1.99) | (91, 1623) | 1.22 | (0.88, 1.69) | 1.19 | (0.86, 1.52) |
| F2-IsoP-M | (96, 1708) | 1.27 | (1.06, 1.53) | (91, 1623) | 1.18 | (0.98, 1.42) | 1.10 | (0.91, 1.29) |
| PGF2α | (96, 1708) | 1.08 | (0.85, 1.39) | (91, 1623) | 0.96 | (0.74, 1.25) | 1.01 | (0.74, 1.27) |
| Derived | ||||||||
| 8-iso-PGF2α chemical | (96, 1708) | 1.49 | (1.09, 2.05) | (91, 1623) | 1.24 | (0.89, 1.74) | 1.20 | (0.85, 1.55) |
| 8-iso-PGF2α enzymatic | (96, 1708) | 0.90 | (0.72, 1.14) | (91, 1623) | 0.85 | (0.68, 1.07) | 0.87 | (0.63, 1.11) |
| Early/Moderate preterm | ||||||||
| Measured | ||||||||
| 8-iso-PGF2α | (42, 1708) | 1.61 | (1.06, 2.44) | (34, 1623) | 1.36 | (0.81,2.28) | 1.22 | (0.72, 1.72) |
| F2-IsoP-M | (42, 1708) | 1.17 | (0.95, 1.48) | (34, 1623) | 1.37 | (1.03, 1.9) | 1.21 | (0.91, 1.51) |
| PGF2α | (42, 1708) | 1.83 | (1.25, 2.68) | (34, 1623) | 1.48 | (0.96, 2.31) | 1.60 | (1.16, 2.05) |
| Derived | ||||||||
| 8-iso-PGF2α chemical | (42, 1708) | 1.33 | (0.86, 2.07) | (34, 1623) | 1.19 | (0.71, 2.03) | 0.98 | (0.47, 1.49) |
| 8-iso-PGF2α enzymatic | (42, 1708) | 1.83 | (1.17, 3.09) | (34, 1623) | 1.47 | (0.94, 2.49) | 1.65 | (1.13, 2.17) |
| Late preterm birth | ||||||||
| Measured | ||||||||
| 8-iso-PGF2α | (165, 1708) | 1.25 | (0.98, 1.59) | (155, 1623) | 1.16 | (0.89, 1.5) | 1.13 | (0.86, 1.39) |
| F2-IsoP-M | (165, 1708) | 1.31 | (1.11, 1.55) | (155, 1623) | 1.26 | (1.07, 1.51) | 1.21 | (1.03, 1.39) |
| PGF2α | (165, 1708) | 1.01 | (0.83, 1.22) | (155, 1623) | 0.97 | (0.79, 1.19) | 0.97 | (0.76, 1.18) |
| Derived | ||||||||
| 8-iso-PGF2α chemical | (165, 1708) | 1.18 | (0.93, 1.51) | (155, 1623) | 1.09 | (0.85, 1.42) | 1.08 | (0.81, 1.34) |
| 8-iso-PGF2α enzymatic | (165, 1708) | 0.91 | (0.77, 1.09) | (155, 1623) | 0.91 | (0.76, 1.1) | 0.92 | (0.73, 1.11) |
Note: Unadjusted models are minimally adjusted for cohort and averaged gestational age (weeks) at sample collection. Adjusted models include maternal age, education, marital status, pre-pregnancy body mass index, averaged gestational age (weeks) at sample collection, and cohort. Early/moderate preterm birth models were not adjusted for smoking status due to a small number of smokers in this group. Preterm birth includes all births occurring prior to 37 weeks of gestation. Non-spontaneous preterm birth includes all preterm births that were of non-spontaneous origin (medically indicated or unknown). Early/moderate preterm birth includes birth occurring prior to 34 completed weeks of gestation. Late preterm birth includes births occurring between 34 and 36 completed weeks of gestation. CI, confidence interval; FTB, full-term birth; OR, odds ratio; PTB, preterm birth.