2. Methods
2.1. Study population
This was a cohort study of demographic data, lifestyle factors and clinical characteristics of stratified selected subjects
in Taiwan from 2004/01/01 to 2005/12/31.
All subjects beyond 12 years old had participated in a questionnaire by the Taiwan National Health Research Institute.
This cohort study was approved by the Institutional Review Board (IRB) of Chung Shan Medical University Hospital.