Absence of an association between gastrointestinal tract surgery and newly diagnosed psoriasis: A nationwide, population-based, nested, case-control study.

Background: Gastrointestinal tract surgeries could disrupt the microbiome and simultaneously cause trauma, which may result in psoriasis.

Objective: To examine associations between gastrointestinal tract surgeries and newly diagnosed psoriasis.

Methods: This nested case-control study included patients with newly diagnosed psoriasis from 2005 to 2013, retrieved from the Taiwan National Health Insurance Research Database.