The use of life tables and survival analysis in testing genetic hypotheses, with an application to Alzheimer's disease.

Because of the late onset of some neuropsychiatric disorders suspected to be under genetic influence, such as Alzheimer's disease, standard techniques for testing genetic hypotheses are difficult to apply to clinical data. The statistical aspects of life table methods and survival probability estimators which can be used to test such hypotheses have been neglected in the psychiatric literature. Two techniques of this kind, the Weinberg morbidity table and the Kaplan-Meier product limit estimator, are applied to real and simulated data. As estimators of lifetime incidence these methods yield roughly equivalent results for both types of data, although from a theoretical standpoint the original Weinberg estimator appears to suffer from logical defects. Parametric models may offer more definitive results, particularly when an estimator of segregation ratio is required. The clinical data in this report were gathered by interviewing relatives of Alzheimer's disease patients sampled through a nursing home survey in metropolitan Baltimore, Maryland during 1980.