1 School of Medicine, China Medical University, Taichung, Taiwan; Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan.
2 Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan.
3 College of Medicine, Tzu Chi University, Hualien, Taiwan; Division of Hepatogastroenterology, Department of Internal Medicine, Taichung Tzu Chi Hospital, Taichung, Taiwan.