Multivariate logistic regression for familial aggregation of two disorders. II. Analysis of studies of eating and mood disorders

Family studies have suggested that eating disorders and mood disorders may coaggregate within families. Previous studies, however, have been limited b y use of univariate modeling techniques and failure to account for the corr elation of observations within families. To provide a more efficient analys is and to illustrate multivariate logistic regression models for familial a ggregation of two disorders, the authors analyzed pooled data from two prev iously published family studies (conducted in Massachusetts in 1984-1986 an d 1986-1987) by using multivariate proband predictive and family predictive models. Both models demonstrated a significant familial aggregation of moo d disorders and familiar coaggregation of eating and mood disorders. The ma gnitude of the coaggregation between eating and mood disorders was similar to that of the aggregation of mood disorders. Similar results were obtained with alternative models, including a traditional univariate proband predic tive model. In comparison with the univariate model, the multivariate model s provided greater flexibility, improved precision, and wider generality fo r interpreting aggregation effects.