A SIMPLE FRAILTY MODEL FOR FAMILY STUDIES WITH COVARIATES

被引:10
作者
BABIKER, A [1 ]
CUZICK, J [1 ]
机构
[1] IMPERIAL CANC RES FUND,DEPT MATH STAT & EPIDEMIOL,LONDON WC2A 3PX,ENGLAND
关键词
D O I
10.1002/sim.4780131608
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
A simple, easily analysed frailty model based on logistic regression and employing only binary frailties is developed and analysed. Methods for testing for frailty and estimates of frailty parameters and covariate effects are presented. The effects of ignoring or mis-specifying frailty are examined in detail and shown to downwardly bias the estimates of covariate effects in a variety of situations, even when frailty is overestimated. When the true frailty is large it can be difficult to estimate accurately because of the flatness of the likelihood. However, it is shown that this does not have a large influence on the estimates of the effects of the observed covariates. Methods for dealing with multiple frailties, for example, sibships and spouse pairs, are also developed. The results are illustrated on a large data set examining the risk factors associated with palmar keratoses.
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页码:1679 / 1692
页数:14
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