A Latent Class Model for Bivariate Binary Responses from Twins
提出一个双变量潜类模型，用于分析同卵和异卵双胞胎的两种疾病共病性，通过遗传倾向性解释疾病关联，并给出遗传度测量。
Summary We propose a latent class model for bivariate binary responses from monozygotic and dizygotic twin pairs. We study the comorbidity of two diseases, where each disease and their association are presumed to be genetically related via latent predispositions. Each twin belongs to one of four latent classes, conceptualized as a 2×2 table and parameterized by the probabilities for the two genetic predispositions and the dependence ratio between them. Both members of a monozygotic pair belong to the same latent class, but a dizygotic pair falls in one of the 4×4 cells from the cross-classification of the four individual classes. The association structure in the 4×4 table is also parameterized by dependence ratios. All parameters of the model are probabilities or ratios of probabilities having clear-cut interpretations, e.g. prevalence and penetrance. We propose a measure of heritability of the complex consisting of the four latent classes which contrasts the concordance of monozygotic and dizygotic twins. We reanalyse two data sets and compare our model with previously used models which are based on other measures of association.