PTH and osteoporosis: The inverse MR association between high serum magnesium and low BMD was completely in contrast with the potential mechanisms of magnesium to affect osteoporosis, which included the promotion to bone mineralization, reduced function of osteoclasts, improved function of osteoblasts, and inducing the homeostasis of calcium by affecting parathyroid hormone (PTH) and 1,25(OH)2-vitamin D (1).