A full quadrivariate ACE Cholesky triangular decomposition was fitted to twin and sibling data. A full AE Cholesky (eFigure 1) was also fitted with no significant change observed in overall fit ( χ102=0, P > .99). Additional models were fitted with a single pathway dropped in each instance and change in model fit determined to be nonsignificant. The best-fitting quadrivariate Cholesky was calculated in this manner. A nonsignificant change in fit was observed when this model was compared with the full AE Cholesky ( χ82=11.61, P = .17). The final model is shown with standardized path coefficients in the Figure (95% CIs available on request) and is summarized with standardized variance components in Table 4.
