1. Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, Heilongjiang 150081, China
2. Department of General Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150081, China
3. Department of Rehabilitation Medicine, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150007, China
4. Heilongjiang Cerebral Palsy Treatment and Management Center, Jiamusi University, Jiamusi, Heilongjiang 154000, China
5. Department of Epidemiology and Biostatistics, School of Public Health, Jiamusi University, Jiamusi, Heilongjiang 154007, China
6. NHC Key Laboratory of Etiology and Epidemiology, Harbin Medical University, Harbin, Heilongjiang 150081, China