Ordinal dose-response modeling approach for the phthalate syndrome.

Background: The phthalate syndrome (PS) is a collection of related male reproductive developmental effects, ranging in severity, that have been observed in rats after gestational exposure to developmentally-toxic phthalates. For statistical purposes, the PS is defined as a single endpoint and one dose-response analysis is conducted, rather than conducting multiple analyses on each individual endpoint.

Objective: To improve dose-response modeling approaches for the PS and other syndromes of effects by accounting for differing severity levels among the endpoints.