Association Between Serum Vitamin D Levels and Visceral Adipose Tissue in Older Adults in Iran: A Cross-Sectional Study From the Amirkola Health and Aging Project

伊朗老年人血清维生素D水平与内脏脂肪组织之间的关联：来自阿米尔科拉健康与老龄化项目的横断面研究