Table 2.
Risk factors for preterm birth (<37 weeks versus ≥37 weeks), N = 927.
| Characteristic | Unadjusted | Adjusteda | ||
|---|---|---|---|---|
| RR [95% CI] | P value | RR [95% CI] | P value | |
| Sociodemographic | ||||
| Age < 20 at conception | 1.58 [1.18, 2.11] | 0.002 | 1.47 [1.10, 1.97] | 0.01 |
| No partner | 1.17 [0.84, 1.63] | 0.35 | ||
| Illiterate | 1.58 [1.14, 2.20] | 0.006 | 1.53 [1.09, 2.15] | 0.01 |
| Nutrition | ||||
| Plasma vitamin A < 20 (µg/dL) | 1.24 [1.19, 1.96] | 0.0008 | 1.25 [0.97, 1.62] | 0.08 |
| Plasma vitamin E < 9.7 (µmol/L) | 0.88 [0.69, 1.13] | 0.31 | ||
| Selenium (mg/mL) | 0.12 | 0.16 | ||
| <0.11 | 1.37 [0.97, 1.96] | 1.40 [0.98, 2.00] | ||
| 0.11-0.12 | 1.15 [0.77, 1.73] | 1.11 [0.74, 1.65] | ||
| 0.12–0.14 | 1.39 [0.98, 1.95] | 1.48 [1.05, 2.08] | ||
| ≥0.14 | Reference | Reference | ||
| Hemoglobin (g/dL) | 0.11 | 0.90 | ||
| <7.0 | 1.29 [0.83, 2.01] | 0.98 [0.64, 1.52] | ||
| 7.0–8.4 | 1.05 [0.74, 1.49] | 0.90 [0.63, 1.28] | ||
| 8.5–10.9 | 0.82 [0.60, 1.11] | 0.78 [0.58, 1.07] | ||
| ≥11.0 | Reference | Reference | ||
| Mid-upper arm circumference (cm) | 0.19 | 0.23 | ||
| ≤23.5 | 1.29 [0.92, 1.81] | 1.32 [0.93, 1.87] | ||
| 23.6–25.0 | 0.95 [0.66, 1.39] | 0.91 [0.63, 1.33] | ||
| 25.1–27.5 | 1.11 [0.78, 1.58] | 1.07 [0.75, 1.53] | ||
| >27.5 | Reference | Reference | ||
| Weight gain (g per week) | <0.0001 | 0.006 | ||
| ≤0 | 1.95 [1.51, 2.53] | 1.60 [1.20, 2.14] | ||
| 1–120 | 1.18 [0.85, 1.65] | 1.12 [0.81, 1.57] | ||
| ≥120 | Reference | Reference | ||
| Height < 150 cm | 0.95 [0.64, 1.40] | 0.79 | ||
| Infections | ||||
| Malaria | 1.53 [1.20, 1.96] | 0.0006 | 1.41 [1.10, 1.81] | 0.006 |
| Hookworm | 1.30 [0.92, 1.84] | 0.13 | 1.19 [0.83, 1.70] | 0.34 |
| Entamoeba coli | 1.49 [1.04, 2.14] | 0.03 | 1.49 [1.04, 2.15] | 0.03 |
| Ascaris lumbricoides | 1.21 [0.73, 1.99] | 0.46 | ||
| Cryptosporidium parvum | 0.88 [0.45, 1.72] | 0.70 | ||
| Entamoeba histolytica | 1.73 [0.92, 3.27] | 0.09 | 1.79 [0.99, 3.26] | 0.06 |
| Strongyloides stercoralis | 1.23 [0.53, 2.84] | 0.63 | ||
| Trichuris trichiura | 1.44 [0.56, 3.65] | 0.45 | ||
| Trichomoniasis | 1.18 [0.92, 1.52] | 0.19 | 1.13 [0.88, 1.45] | 0.35 |
| Syphilis | 1.28 [0.80, 2.05] | 0.31 | ||
| Vaginal candidiasis | 1.10 [0.66, 1.85] | 0.72 | ||
| Gonorrhea | 1.83 [0.88, 3.85] | 0.11 | 1.68 [0.84, 3.35] | 0.14 |
| HIV/AIDS | ||||
| WHO HIV disease stage ≥ 2 | 1.60 [1.26, 2.03] | 0.0001 | 1.40 [1.11, 1.78] | 0.005 |
| CD4 count < 200 cells/mm3 | 0.92 [0.64, 1.32] | 0.65 | ||
| Viral load ≥ 50,000 copies/mL | 1.02 [0.74, 1.42] | 0.89 | ||
| Other clinical variables | ||||
| Twins | 1.50 [0.85, 2.64] | 0.16 | 1.85 [0.94, 3.66] | 0.07 |
| Prehypertension or hypertensionb | 1.25 [0.98, 1.58] | 0.07 | 1.27 [1.01, 1.60] | 0.04 |
ARR: risk ratio; CI: confidence interval.
aAdjusted for age < 20 years, literacy, plasma vitamin A < 20 µg/dL, selenium, mid-upper arm circumference, weight gain, malaria, hookworm, Entamoeba coli, Entamoeba histolytica, trichomoniasis, gonorrhea, WHO HIV disease stage ≥ 2, twins, and prehypertension or hypertension.
bSystolic blood pressure >120 mmHg or diastolic blood pressure >80 mmHg.