Prevalence of psoriasis and associated risk factors in China: protocol of a nationwide, population-based, cross-sectional study.

The study has been reviewed and approved by the ethics committee of the Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College (Nanjing, China). A written informed consent will be obtained from all participants before the questionnaire survey. Findings of the study will be disseminated through publications in peer-reviewed journals.