Table 4
Summary of the results from the previous and present study
| Iowa | New Jersey | North Carolina | Colorado | Nova Scotia | Taiwan | Norway | |
| Type of study | Case control, population based | Cross sectional, population based, 80938 infants | Case control, population based | Cross sectional, population based, 1244 infants |
Cross sectional, population based, 50755 infants | Cross sectional, population based, 18025 infants | Cross sectional, population based, 137145 infants |
| Study population | 159 Low birth weight 795 Controls 187 Small for gestational age 935 Controls 342 Preterm 1710 Controls |
1853 Low birth weight 4082 Small for gestational age 7167 Preterm |
178 Low birth weight 244 Preterm |
72 Low birth weight 68 Preterm 333 Controls |
2382 Low birth weight 4673 Small for gestational age 2659 Preterm |
456 Low birth weight 719 Preterm |
6249 Low birth weight 5372 Small for gestational age 7886 Preterm |
| Exposure-outcome relations (OR (95% CI)): | |||||||
| Low birth weight | 1.3 (0.8–2.2) | 1.42 (0.90–2.20) | 1.3 (0.8–2.1)4-150 | 2.1 (1.0–4.8) | 1.04 (0.92–1.18)4-150 | 0.90 (0.75–1.09)4-151 | 0.97 (0.89–1.06) |
| 1.5 (0.8–3.0)4-150 | |||||||
| Small for gestational age | 1.8 (1.1–2.9) | 1.50 (1.14–1.94) | NA | 5.9 (2.0–17.0)4-150 4-151 | 1.08 (0.99–1.18)4-150 | NA | 1.00 (0.91–1.10) |
| Preterm delivery | 1.1 (0.7–1.6) | NS | 0.9 (0.6–1.5)4-150 | 1.0 (0.3–2.8) | 0.97 (0.87–1.09) | 1.34 (1.11–1.62) | 0.91 (0.84–0.99) |
