Wikipedia cites one 1970 study by Voors claiming that drinking hard water lessens the odds of dying from atherosclerosis. The stud itself even makes some bolder claims stratified by race, namely that lithium was protective for whites and vanadium for non-whites.
A much more recent (2008) article by Burton makes no mention of either lithium or vanadium, but says:
The idea that hard water—particularly that with higher magnesium concentrations—helps ward off cardiovascular problems has been around for 50 years. However, due to the ecologic nature of most studies, uncontrolled confounding factors, and the different variables and outcomes measured, no firm conclusions have ever been drawn. The WHO is therefore coordinating worldwide efforts to compare cardiovascular morbidity before and after changes in the calcium/magnesium content of water supplies.
Approximately 10 years later, has anything conclusive come out this? Is hard water in general protective of cardiovascular problems? Is any mineral in particular important?