Serum 25(OH)D Level and Parathyroid Hormone in Chinese Adult Population: A Cross-Sectional Study in Guiyang Urban Community from Southeast of China oleh Zhang Qiao, Shi Li-xing, Peng Nian-chun, Xu Shu-jing, Zhang Miao, Li Hong, Zhuang Hui-jun, Gong Ming-xian, Zhang Song, Wang Rui, Hu Ying, Zhang Jing-lu, Chen Shuang