Table VIII.
Comparison of studies estimating the heritability of BPD
| Parker et al9 | Bhandari et al10 | Lavoie et al11 | Current study | ELGAN validation15 | ||
|---|---|---|---|---|---|---|
| Years subjects accrued | 1976–1990 | 1994–2004 | 1993–2006 | 1997–2015 | 2002–2004 | |
| Population size | 1872 | 450 twin pairs | 478 | 2198 | 1506 | |
| Number ot twin pairs analyzed | 108 | 252 | 159 | 250 | 105 | |
| Restrictions | <1500 g birth weight survival >28 d | ≤32 wk gestational age survrval ≥36 wk PMA | ≤30 wk gestational age | ≤28 wk gestational age survival ≥36 wk PMA | <28 wk gestational age survival ≥36 wk PMA | |
| Chonomcity known | No | Yes | Yes | Yes | Yes | |
| Zygosity known | No | Yes | Yes | Yes | No | |
| BPD definition | O2 at 28 d + abnormal CXR + symptoms | O2 at 36 wk PMA + abnormal CXR | O2 at 36 wk PMA or discharge NIH consensus criteria | O2 at 36 wk PMA O2 CPAP/RA at 36 wk PMA NIH consensus critena | O2 at 36 wk | |
| Sex (male) | 57% of BPD 46.3% of cohort | 54% of cohort | 55.7% of cohort | 56% of BPO 52% of cohort | ||
| Gestational age (wk) | Overall | 29.7 ± 2.5 | 27.9 ± 1.8 | 26.7 (±1.3) | 25.9(±1.1) | |
| mean ± SD | No BPD | 30.4 ± 2.3 | 27.0 (±1.2) | 26.2 (±1.0) | ||
| BPD | 27.7 ± 2.0 | 26.2 (±1.4) | 25.5 (±1.2) | |||
| Birth weight (g) | Overall | 1397 ± 443 | 1116 ± 314 | 950 (±208) | 873 (±189) | |
| mean ± SD | No BPD | 1211 ± 209 | 1014 (±198) | 925 (±169) | ||
| BPD | 929 ± 225 | 855 (±185) | 813 (±193) | |||
| % cohort with BPD | 17.5% | 19.8% moderate, 7.5% severe | 41% | |||
| Analysis methods | OR of BPD in twin A and twin B | ACE model* | ACE model* assuming %C = 0 (AE model) | ACE model* | ACE model* | |
| Heritability estimate | aOR 12.3 (P < .01) | unadjusted %A = 63.6% adjusted %A= 53% 95% CI (16%–89%) |
unadjusted %A = 82% 95% CI (70%–97%) |
unadjusted %A = 0.0% 95% CI (0%–43%) |
unadjusted %A = 6.5% 95% CI (0%–67%) |
CXR, chest radiograph; RA, room air.
*
ACE model: decomposes the total varation in “liability” of disease into additive genetic (A), common or shared environmental (C), and unique or unshared environmental (E) effects.