Associations of sleep quality and exercise frequency and the risk of coronary heart disease in Chinese urban elderly: a secondary analysis of cross-sectional data

• Jiujing LinShandong First Medical University
• Huichen YaoShandong First Medical University
• Jia LiShandong First Medical University
• Chenyang HouShandong Tumor Hospital
• Xia SongShandong Maternal and Child Health Hospital
• Kang AnShandong First Medical University
• Shoufeng TianShandong Center for Disease Control and Prevention
• Xiaoliang LiShandong First Medical University
• Yun WangShandong First Medical University
• Qing GuoShandong First Medical University
• Weihua LiuShandong First Medical University
• Hengxia Zhao
• Jinjie He
• Qingzhi HouShandong First Medical University