Table 2. Univariate biometric genetic model for binary measures of physical activity in UWTR same-sex twin pairs.
Model* | Estimates of variance components† | Test of model fit | |||||
A | C | E | χ2 | df | P value | AIC‡ | |
60 minute cut-point | |||||||
ACE | 0.27 (0.00, 0.53) | 0.16 (0.00, 0.46) | 0.57 (0.47, 0.67) | – | – | – | – |
AE | 0.45 (0.34, 0.54) | – | 0.55 (0.46, 0.66) | 0.77 | 1 | 0.38 | −1.23 |
CE | – | 0.39 (0.30, 0.48) | 0.61 (0.52, 0.70) | 1.76 | 1 | 0.18 | −0.24 |
150 minute cut-point | |||||||
ACE | 0.11 (0.00, 0.39) | 0.18 (0.00, 0.36) | 0.71 (0.61, 0.81) | – | – | – | – |
AE | 0.31 (0.21, 0.40) | – | 0.69 (0.60, 0.79) | 0.91 | 1 | 0.34 | −1.09 |
CE | – | 0.28 (0.19, 0.36) | 0.72 (0.64, 0.81) | 0.31 | 1 | 0.58 | −1.69 |
ACE refers to a model that includes additive genetics (A), common environment (C), and unique environment (E), AE only includes additive genetics and unique environment, and CE only includes common and unique environment;
Proportion of variance (and 95% confidence interval) due to additive genetics, shared environment, and unique environment factors according to each model;
Akaike's information criterion (AIC) is a global measure of goodness of fit, with the best-fitting and most parsimonious models shown in bold.