Low serum magnesium concentrations predict cardiovascular and all-cause mortality.

BACKGROUND

Low serum magnesium (Mg(++)) levels are associated with future development of left ventricular hypertrophy independently of common cardiovascular risk factors, as recently demonstrated in the five-year follow-up of the population-based Study of Health in Pomerania (SHIP). As left ventricular hypertrophy has significant prognostic implications, we hypothesized that serum Mg(++) levels are associated with cardiovascular mortality.

METHOD AND RESULTS

All-cause mortality and cardiovascular mortality were analyzed in relationship to serum Mg(++) concentrations at baseline by Cox proportional hazard model in SHIP (n=4203, exclusion of subjects with Mg(++) supplementation). The median duration of mortality follow-up was 10.1 years (25th percentile: 9.4 years, 75th percentile: 10.8 years; 38,075 person-years). During the follow-up, 417 deaths occurred. Mortality in subjects with Mg(++)≤0.73 mmol/l was significantly higher for all-cause deaths (10.95 death per 1000 person years), and cardiovascular deaths (3.44 deaths per 1000 person years) in comparison to higher Mg(++) concentrations (1.45 deaths from all-cause per 1000 person years, 1.53 deaths from cardiovascular cause per 1000 person years). This association remained statistically significant after adjustment for multiple cardiovascular risk factors, including arterial hypertension, and antihypertensive therapy including diuretics (log-rank-test p=0.0001 for all-cause mortality, and p=0.0174 for cardiovascular mortality).

CONCLUSIONS

Low serum Mg(++) levels are associated with higher all-cause mortality and cardiovascular mortality. This corresponds well with recent findings that hypomagnesemia is associated with the increase of left ventricular mass over the following years.