Table 3. Cosibling Analyses for Gestational Age at Birth in Association With IHD Risk in Sweden From 1973 to 2015.
| Characteristic | No. of Cases | HR (95% CI)a |
|---|---|---|
| Attained ages 18-43 y | ||
| Preterm (<37 wk) | 82 | 1.35 (0.87-2.09) |
| Early term (37-38 wk) | 228 | 1.12 (0.87-1.44) |
| Full term (39-41 wk) | 902 | 1 [Reference] |
| Per additional week (trend) | 0.94 (0.88-0.99) | |
| Attained ages 18-29 y | ||
| Preterm (<37 wk) | 40 | 1.46 (0.82-2.61) |
| Early term (37-38 wk) | 108 | 0.97 (0.69-1.36) |
| Full term (39-41 wk) | 433 | 1 [Reference] |
| Per additional week (trend) | 0.93 (0.86-1.00) | |
| Attained ages 30-43 y | ||
| Preterm (<37 wk) | 42 | 1.23 (0.69-2.31) |
| Early term (37-38 wk) | 120 | 1.30 (0.87-1.94) |
| Full term (39-41 wk) | 469 | 1 [Reference] |
| Per additional week (trend) | 0.95 (0.87-1.04) |
Abbreviations: HR, hazard ratio, IHD, ischemic heart disease.
a
Adjusted for shared familial (genetic and/or environmental) factors in addition to specific child characteristics (birth year, fetal growth, birth order, and congenital anomalies) and maternal characteristics (age, education, birth country or region, body mass index [calculated as weight in kilograms divided by height in meters squared], smoking, preeclampsia, other hypertensive disorders, and diabetes).