Vascular calcification & Magnesium deficiency --
Significant association between the presence of peripheral vascular calcification and lower serum magnesium in hemodialysis patients.

“...CONCLUSION:
Hypomagnesemia is significantly associated with the presence of vascular calcification of the hand arteries, independent of serum calcium and phosphate levels. These results suggest that higher serum magnesium concentrations may play an important protective role in the development of vascular calcification in hemodialysis patients, and that magnesium concentration of dialysis fluid may be reconsidered in view of preventing vascular calcification in hemodialysis patients...” http://www.ncbi.nlm.nih.gov/pubmed/17969489