Table 2.
Univariate and multivariate logistic regression of factors associated with preterm birth.
| Variable | Crude | Adjusted | ||
|---|---|---|---|---|
| OR | 95% CI | OR | 95% CI | |
| Mother age | ||||
| 20 ≤ Age ≤ 25 | 1.00 | – | 1.00 | – |
| 25 < Age ≤ 30 | 0.90 | 0.89–0.91 | 0.87 | 0.86–0.88 |
| 30 < Age ≤ 35 | 0.96 | 0.95–0.97 | 0.90 | 0.88–0.91 |
| Age > 35 | 1.11 | 1.09–1.13 | 1.01 | 0.99–1.02 |
| Monthly income | ||||
| Dependent | 1.00 | – | 1.00 | – |
| < NT$20,000 | 0.96 | 0.95–0.97 | 0.96 | 0.95–0.98 |
| NT$20,000–$40,000 | 0.98 | 0.97–0.99 | 1.00 | 0.98–1.01 |
| > NT$40,000 | 1.13 | 1.11–1.14 | 1.13 | 1.11–1.15 |
| Individual obstetric history | ||||
| Multifetal pregnancy | 9.46 | 9.15–9.77 | 9.03 | 8.73–9.33 |
| Placental abnormality | 1.77 | 1.75–1.79 | 1.72 | 1.70–1.74 |
| Diabetes mellitus complicating pregnancy | 1.48 | 1.46–1.50 | 1.41 | 1.39–1.42 |
| Vaginal infection | 1.06 | 1.05–1.08 | 1.00 | 0.98–1.01 |
| Autoimmune disease | 1.35 | 1.32–1.39 | 1.29 | 1.25–1.32 |
| Hypertension complicating pregnancy | 3.36 | 3.29–3.43 | 3.16 | 3.09–3.23 |
| Psychological factor(s) | 1.28 | 1.26–1.29 | 1.25 | 1.24–1.27 |
| Periodontal disease | ||||
| No PD | 1.00 | – | 1.00 | – |
| Mild PD | 1.08 | 1.07–1.09 | 1.05 | 1.04–1.06 |
| Advanced PD | 1.12 | 1.10–1.14 | 1.09 | 1.07–1.11 |