Genetic model-fitting results: variance components (with 95% CI)
| Genetic model | Twins included | Modelled as next dizygotic pair concordant | Additive genetic component (A) | Common environmental (C) or dominant genetic (D) component | Unique environmental component (E) |
| ADE | All | No | 0.00 (0.00 to 0.80) | 0.73 (0.00 to 0.85) | 0.27 (0.15 to 0.45) |
| AE | All | No | 0.71 (0.53 to 0.84) | – | 0.29 (0.16 to 0.47) |
| ACE | All | Yes | 0.52 (0.04 to 0.85) | 0.21 (0.00 to 0.58) | 0.27 (0.15 to 0.45) |
| AE | All | Yes | 0.76 (0.60 to 0.86) | – | 0.24 (0.14 to 0.40) |
| ADE | Sporadic | No | 0.00 (0.00 to 0.75) | 0.64 (0.00 to 0.81) | 0.36 (0.19 to 0.59) |
| AE | Sporadic | No | 0.61 (0.38 to 0.78) | – | 0.39 (0.22 to 0.62) |
| ACE | Sporadic | Yes | 0.36 (0.00 to 0.80) | 0.30 (0.00 to 0.63) | 0.35 (0.19 to 0.57) |
| AE | Sporadic | Yes | 0.70 (0.52 to 0.83) | – | 0.30 (0.17 to 0.48) |