1. Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Centre, 38 Xueyuan Road, Haidian District, Beijing 100191, China
2. Department of Preventive Medicine, College of Medicine, Shihezi University, Shihezi 832002, China
3. Department of Physiology, Capital Medical University, Beijing 100069, China
4. Department of Statistics, Graduate School of Arts and Sciences, Columbia University, New York, NY 10027, USA
5. Department of Orthopedics, Tianjin Fifth Central Hospital, Tianjin 300450, China
6. Shantou-Oxford Clinical Research Unit, Shantou University Medical College, Shantou 515041, China
7. Department of Endocrinology and Metabolism, People’s Hospital, Peking University, Beijing 100044, China