Doubly truncated data arise when event times are observed only if they fall within subject-specific, possibly random, intervals. While non-parametric methods for survivor function estimation using doubly truncated data have been intensively studied, only a few methods for fitting regression models have been suggested, and only for a limited number of covariates. In this article, we present a method to fit the Cox regression model to doubly truncated data with multiple discrete and continuous covariates, and describe how to implement it using existing software. The approach is used to study the association between candidate single nucleotide polymorphisms and age of onset of Parkinson's disease.
The work was supported by NINDS grant R01NS094610‐01, and the Harvard NeuroDiscovery Center. The second author was supported by Grant MTM2014‐55966‐P of the Spanish Ministerio de Economía y Competitividad.