TABLE 1—
Sociodemographic, Biomedical, and Behavioral Characteristics of the Study Sample: Chicago, Ill, November 1, 1997–October 31, 2000
| Percentage (No.) of VLBW Cases (n = 104) | Percentage (No.) Of NLBW Controls (n = 208) | Odds Ratio (95% Confidence Interval) | |
| Maternal age, y | |||
| < 20 | 27 (28) | 31 (62) | 1.1 (0.6, 2.1) |
| 20–24 | 25 (26) | 31 (63) | 1.0 |
| 25–29 | 19 (20) | 21 42) | 1.2 (0.6, 2.3) |
| ≥30 | 28 (29) | 17 (35) | 2.0 (1.0, 3.9) |
| Education, y | |||
| < 12 | 31 (31) | 39 (77) | 0.5 (0.3, 0.9) |
| 12 | 34 (34) | 39 (77) | 0.6 (0.3, 1.0) |
| > 12 | 36 (36) | 23 (46) | 1.0 |
| Living arrangements | |||
| Married | 23 (22) | 15 (31) | 1.0 |
| Unmarried, living together | 12 (11) | 18 (36) | 0.4 (0.2, 1.0) |
| Unmarried, not together | 65 61) | 67 (134) | 0.6 (0.3, 1.2) |
| Income quartile, $a | |||
| 1: < 5000 | 28 (20) | 29 (31) | 0.8 (0.3, 1.9) |
| 2: 5000–15 999 | 23 (16) | 29 (31) | 0.7 (0.3, 1.6) |
| 3: 16 000–30 999 | 27 (19) | 23 (25) | 1.0 (0.4, 2.3) |
| 4: ≥31 000 | 23 (16) | 19 (20) | 1.0 |
| Payment method | |||
| Medicaid | 62 (58) | 68 (138) | 0.8 (0.5, 1.2) |
| Other payments | 38 (35) | 32 (63) | 1.0 |
| Prenatal care | |||
| Earlyb | 69 (71) | 61 (127) | 1.0 |
| Late or none | 31 (32) | 39 (81) | 0.7 (0.4, 1.2) |
| Pregnancies, No. | |||
| 1–3 | 86 (89) | 85 (171) | 1.0 |
| ≥4 | 14 (14) | 15 (31) | 0.9 (0.4, 1.7) |
| Cigarette smoking | |||
| Smoker | 30 (31) | 21 (43) | 1.6 (1.0, 2.8) |
| Nonsmoker | 70 (72) | 79 (163) | 1.0 |
| Alcohol consumption | |||
| Yes | 18 (19) | 15 (32) | 1.2 (0.7, 2.3) |
| No | 82 (84) | 85 (176) | 1.0 |
Note. VLBW = very low birthweight; NLBW = non–low-birthweight
a For household income, 43% are missing data.
b Defined as initiation in the first trimester.