TABLE 2.
Tetrachoric correlations and estimates for asthma at ages 3 and 7, estimates for the model without asthma polygenic risk score
| MZ (n) | MZ cor | DZ same‐sex (n) | DZ opposite‐sex (n) | DZ cor | Proportion due to A heritability | Proportion due to C | Proportion due to E | |
|---|---|---|---|---|---|---|---|---|
| Standardized liability variance components | ||||||||
| Age 3 | 7,329 | 0.954 | 7,177 | 7,035 | 0.555 | 0.796 | 0.157 | 0.046 |
| Age 7 | 7,329 | 0.904 | 7,177 | 7,035 | 0.452 | 0.904 | 0* | 0.096 |
| Liability covariance | ||||||||
| Age 3 and 7 | rliability: 0.746 | R(A) = 0.807 | NA | R(E) = 0.934 | ||||
| Contribution to rliability | 0.685 | NA | 0.062 | |||||
| Proportions | 0.917 | NA | 0.083 | |||||
* Fixed to zero. Adjusted for gender.
Abbreviations: AAPRS, asthma risk score; C, shared environment component; cor, correlation; DZ, dizygotic; E, non‐shared environment component; MZ, monozygotic; n, number of twin pairs including twins with missing data; NA, not applicable; R(A), genetic correlation; R(E), environmental correlation.