Table 3. Standardized Parameter Estimates and Test Statistics for ACE Constraint Models.
| Categorization Method: Pubertal Status (Klump et al. (2003)method) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Models | Pre-pubertal Twins (N=166; 83 pairs) |
Pubertal Twins (N = 142; 71 pairs) |
Young Adult Twins (N = 324; 162 pairs) |
||||||||||
| A | C | E | A | C | E | A | C | E | −2lnL (df) |
−2lnLΔ (df) |
p | AIC | |
| Fully Unconstrained |
.00 (.00–.52) |
.34 (.00–.51) |
.66 (.47–.87) |
.71 (.17–.82) |
.00 (.00–.48) |
.29 (.18–.47) |
.56 (.21–.68) |
.00 (.00–.30) |
.44 (.33–.58) |
1695.554 (618) |
-- | -- | 459.554 |
| Constrain Pre-pubertal & Pubertal |
.35 (.00–.64) |
.17 (.00–.53) |
.48 (.36–.64) |
-- | -- | -- | .56 (.21–.67) |
.00 (.00–.30) |
.44 (.33–.58) |
1704.036 (621) |
8.482 (3) |
.04 | 462.036 |
|
Constrain Pubertal & Adult |
.00 (.0–.52) |
.34 (.00–.51) |
.66 (.47–.87) |
.60 (.32–.69) |
.00 (.00–.25) |
.40 (.31–.50) |
-- | -- | -- |
1698.988 (621) |
3.434 (3) |
.33 | 456.988 |
| Fully Constrained | .55 (.21–.63) |
.00 (.00–.30) |
.45 (.37–.55) |
-- | -- | -- | -- | -- | -- | 1708.034 (624) |
12.48 (6) |
.05 | 460.034 |
| Categorization Method: Menarcheal Status (Rowe et al. (2002)method) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pre-menarche Twins (N=202; 101 pairs) |
Post-menarche Twins (N = 108; 54 pairs) |
Young Adult Twins (N = 324; 162 pairs) |
|||||||||||
| A | C | E | A | C | E | A | C | E | −2lnL (df) |
−2lnLΔ (df) |
p | AIC | |
| Fully Unconstrained |
.39 (.00–.60) |
.04 (.00–.50) |
.56 (.40–.78) |
.51 (.00–.81) |
.18 (.00–.67) |
.32 (.18–.55) |
.56 (.21–.68) |
.00 (.00–.30) |
.44 (.32–.58) |
1700.581 (618) |
-- | -- | 464.581 |
| Constrain Pre-menarche & Post-menarche |
.40 (.00–.65) |
.12 (.00–.52) |
.47 (.35–.63) |
-- | -- | -- | .56 (.21–.68) |
.00 (.00–.30) |
.44 (.32–.58) |
1704.275 (621) |
3.694 (3) |
.30 | 462.275 |
| Constrain Post-menarche & Adult |
.39 (.00–.60) |
.04 (.00–.50) |
.56 (.40–.78) |
.59 (.25–.69) |
.00 (.00–.30) |
.41 (.31–.52) |
-- | -- | -- | 1703.281 (621) |
2.70 (3) |
.44 | 461.281 |
|
Fully Constrained |
.55 (.23–.63) |
.00 (.00–.28) |
.45 (.37–.55) |
-- | -- | -- | -- | -- | -- |
1707.800 (624) |
7.219 (6) |
.30 | 459.800 |
Note: A = additive genetic effects; C = shared environmental effects; E = non-shared environmental effects; AIC = Akaike’s Information Criteria; −2lnL = minus 2 times the log likelihood; −2lnLΔ = differences in −2lnL values between model 1 and each of the constrained models. Pre-pubertal = pre-pubertal group; Pubertal = pubertal group; Adult = young adult group; Pre-menarche = pre-menarche group; Post-menarche = post-menarche group. Standardized parameter estimates are listed in columns labeled A, C, E with the 95% confidence intervals within parentheses. Dashed lines for constrained models indicate that parameter estimates were constrained to be equal to those for the preceding group. The best-fitting model is noted in bolded text.