1. Department of Health Statistics, School of Public Health, Shanxi Medical University, China.
2. Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, China.
3. Department of Surgery, General Hospital of Datong Coal Mining Group, China.
4. Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
5. Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.