The study in question follows the intake of magnesium and its relation to heart disease and all cause mortality. This study finds that serum magnesium concentration, independant of other risk factors, was inversely associated with all cause mortality. They found that study participants with higher blood magnesium levels had an approximately 30% reduced risk of dying from ischaemic heart disease. The study was performed on a sample of participants over 12,000 in size, from ages 25-74 and was continued for 19 years. The authors also make careful note that serum magnesium concentrations (measured blood levels), are also not totally indicative of magnesium status. The particpants in this study used no magnesium supplementation at all and obtained all their magnesium from their diet. The authors also note that approximately 23% of the followed sample had blood magnesium levels of <0.80 mmol/L which is low enough to warrant a diagnosis of hypomagensia, or severe magnesium deficiency. This study shows that magnesium plays an important role in maintaining the health of the heart, and makes it clear that obtaining adequate magnesium from your diet is essential for heart health.