Serum magnesium concentrations and all-cause, cardiovascular, and cancer mortality among U.S. adults: results from the NHANES I Epidemiologic Follow-up Study

Authors: ZHANG, XI - Shanghai Jiaotong University; XIA, JIN - Indiana University; DEL GOBBO, LIANA - Stanford University; HRUBY, ADELA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; DAI, QI - Vanderbilt University; SONG, YIQING - Indiana University

Submitted to: Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2017
Publication Date: 10/1/2017
Citation: Zhang, X., Xia, J., Del Gobbo, L.C., Hruby, A., Dai, Q. 2017. Serum magnesium concentrations and all-cause, cardiovascular, and cancer mortality among U.S. adults: results from the NHANES I Epidemiologic Follow-up Study. Clinical Nutrition. 37(5):1541-1549. https://doi.org/10.1016/j.clnu.2017.08.021.
DOI: https://doi.org/10.1016/j.clnu.2017.08.021

Interpretive Summary: Serum magnesium, the magnesium that is circulating in the blood, is the most common way to measure magnesium status in the body. Magnesium is thought to be an important mineral in the body, helping to manage energy metabolism, bone health, nerve function, along with a host of other functions. Researchers wanted to know if levels of serum magnesium could be used to predict early death of Americans. They studied 14,353 Americans aged 25-74 years old who had their serum magnesium concentrations originally measured in 1971-1975. They followed these individuals for up to 40 years, and counted the number who died in this period, as well as recorded the cause of death. The researchers found that 9012 deaths occurred, including 3959 deaths from heart disease, 1923 deaths from cancer, and 708 deaths due to stroke. Researchers found that very low levels of serum magnesium (<0.7 mmol/L) tended to be associated with higher risk of death from any cause, as well as for death due to cancer and heart disease. The strongest risk of low serum magnesium was for death due to stroke, in which those with very low magnesium levels had over double the risk of dying from stroke than those with higher levels of blood magnesium.

Technical Abstract: BACKGROUND: Few studies have examined the associations of serum magnesium (Mg) concentrations with total and cause-specific mortality in a nationally representative sample of US adults. We investigate the dose-response relationships of baseline serum Mg concentrations with risk of mortalities in a large, nationally representative sample of US adults. METHODS: We analyzed prospective data of 14,353 participants aged 25-74 years with measures of serum Mg concentrations at baseline (1971-1975) from the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study (NHEFS). Mortality data was linked through December 31, 2011. We estimated the mortality hazard ratios (HRs), for participants within serum Mg categories of <0.7, 0.7-0.74, 0.75-0.79, 0.8-0.89 (referent), 0.9-0.94, 0.95-0.99, and >/=1.0 mmol/L using weighted multivariate-adjusted Cox proportional hazards models. RESULTS: During a median follow-up of 28.6 years, 9012 deaths occurred, including 3959 CVD deaths, 1923 cancer deaths, and 708 stroke deaths. The multivariate-adjusted HRs (95% CIs) of all-cause mortality across increasing categories of Mg were 1.34 (1.02, 1.77), 0.94 (0.75, 1.18), 1.08 (0.97, 1.19), 1.00 (referent), 1.05 (0.95, 1.16), 0.96 (0.79, 1.15), and 0.98 (0.76, 1.26). Similar trends were observed for cancer (HRs for serum Mg < 0.7: 1.39, 95% CI: 0.83, 2.32) and CVD mortality (HRs for serum Mg < 0.7: 1.28, 95% CI: 0.81, 2.02) but were not statistically significant. An elevated risk for stroke mortality was observed among participants with serum Mg < 0.70 mmol/L (HR: 2.55, 95% CI: 1.18, 5.48). CONCLUSIONS: Very low serum Mg concentrations were significantly associated with an increased risk of all-cause mortality in US adults.