1. Shandong University; Dept of Medical Statistics College of Public Health; No 44 Wenhua Xi Lu Shandong Province Jinan China 250012
2. Shandong Provincial Academy of Medical Science; Shandong Provincial Institute of Dermatology and Venerology; 57 Jiyan Lu Huaiyin Qu Jinan Shandong China 250022
3. Beijing University of Chinese Medicine; Centre for Evidence-Based Chinese Medicine ; 11 Bei San Huan Dong Lu, Chaoyang District Beijing China 100029