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.
The age, sex, body mass index (BMI), education, physical activity, alcohol drinking and smoking habits, past history, family history, and simple food frequency of each subject were requested by the questionnaire.
The World Health Organization (WHO) has stated that physical activity includes activities of skeletal muscles that induce body movements that require energy consumption, including walking, cycling, and so on.