Role of metabolic characteristics in the co-occurrence of insomnia, Alzheimer’s disease, and Parkinson’s disease: a Mendelian randomization study - Liu, Chengyong; Wang, Chi; Jiang, Jing; Bo, Yuyang; Nan, Lixiu; Zhang, Ying; Zhu, Kongxi; Wang, Xiaoqiu; Feng, Xinxin; Lian, Xiaoyang; Qin, Shan (Frontiers in Aging Neuroscience, 2025)