Modelling ordinal responses from co-twin control studies

Modelling ordinal responses from co-twin control studies.

The co-twin control design has been widely used in studying the effects of environmental factors on the development of diseases. For binary outcomes that arise from co-twin control studies, the conditional likelihood method is commonly used. This approach, however, does not readily extend to ordinal response data because the standard conditional likelihood does not exist for cumulative logit or...

Co-twin control studies: vitamin C and the common cold.

Modelling of Correlated Ordinal Responses, by Using Multivariate Skew Probit with Different Types of Variance Covariance Structures

In this paper, a multivariate fundamental skew probit (MFSP) model is used to model correlated ordinal responses which are constructed from the multivariate fundamental skew normal (MFSN) distribution originate to the greater flexibility of MFSN. To achieve an appropriate VC structure for reaching reliable statistical inferences, many types of variance covariance (VC) structures are considered ...

Modelling blood pressure as a continuous outcome variable in a co-twin control study.

The co-twin control study is a popular research design that is used in many research disciplines, including epidemiology, medicine, and the behavioural sciences. In co-twin control studies of monozygotic (MZ) exposure discordant twin pairs, the appropriate statistical tests used to analyse data from continuous outcome variables are the parametric paired sample t test or the non-parametric Wilco...

Osteoporosis in rheumatoid arthritis. A monozygotic co-twin control study.

OBJECTIVE To quantify the magnitude and distribution of osteoporosis in rheumatoid arthritis (RA). METHODS Bone mineral density (BMD) was measured by dual x-ray absorptiometry, in a monozygotic co-twin control study. RESULTS BMD was reduced at most skeletal sites in the twin with RA compared with the co-twin (lumbar spine 4.6%, femoral neck 9.7%, total body 5.7%). Differences in lean soft t...