Table 5.
Model fit indices and tests of quantitative and qualitative sex differences from univariate twin modelling of blackout and passing out.
| χ2 | df | p-value | Δχ2 | df | p-value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Blackout Occurrence | ||||||||||||
| Base Model | 2.83 | 8 | 0.94 | -- | -- | -- | ||||||
| mACE=fACE | 5.52 | 10 | 0.85 | 2.69 | 2 | 0.26 | ||||||
| OS rg = 0.5 | 3.41 | 9 | 0.95 | 0.58 | 1 | 0.45 | ||||||
| Blackout Susceptibility | ||||||||||||
| Base Model | 3.36 | 8 | 0.91 | -- | -- | -- | ||||||
| mACE = fACE | 8.29 | 10 | 0.60 | 4.93 | 2 | 0.09 | ||||||
| OS rg = 0.5 | 3.79 | 9 | 0.92 | 0.43 | 1 | 0.51 | ||||||
| Passing Out Occurrence | ||||||||||||
| Base Model | 10.20 | 8 | 0.25 | -- | -- | -- | ||||||
| mACE = fACE | 17.84 | 10 | 0.06 | 7.64 | 2 | 0.02 | ||||||
| Passing Out Susceptibility | ||||||||||||
| Base Model | 8.37 | 8 | 0.40 | -- | -- | -- | ||||||
| mACE = fACE | 14.13 | 10 | 0.17 | 5.76 | 2 | 0.06 | ||||||
| OS rg = 0.5 | 8.37 | 9 | 0.50 | -- | -- | -- | ||||||
Note: m = men, f = women, ACE = genetic (A), shared environmental (C), and nonshared environmental (E) influences, OS = opposite sex.
mACE = fACE: test of quantitative sex differences (equating parameter estimates for men and women); OS rg = 0.5: test of qualitative sex differences (constraining OS genetic correlation to 0.5, or the genetic correlation for same-sex dizygotic twins).