Relation of Magnesium Intake With Cardiac Function and Heart Failure Hospitalizations in Black Adults: The Jackson Heart Study.

Abstract

Little is known about magnesium intake and risk of heart failure (HF) hospitalizations, particularly in blacks. We hypothesize that magnesium intake relates to HF hospitalization in blacks. From the Jackson Heart Study cohort (n=5301), we studied 4916 blacks recruited during 2000 to 2004 in Jackson (Mississippi), who completed an 158-item Food-Frequency Questionnaire that included dietary supplements. Daily magnesium intake derived from the questionnaire was divided by the body weight to account for body storage and stratified by quartiles (0.522-2.308, 2.309-3.147, 3.148-4.226, and ≥4.227 mg magnesium intake/kg). Cox proportional hazards modeling assessed the association between quartiles of magnesium intake/kg and hospitalizations for HF adjusting for HF risk, energy intake, and dietary factors. The cohort had a mean age=55.3 (SD=12.7 years) and composed of 63.4% women, 21.6% diabetes mellitus, 62.7% hypertension, 7.1% coronary disease, and 2.8% with known HF. When compared with participants in the first quartile of magnesium intake/kg, those with higher magnesium intake (>2.308 mg/kg) had decreased risk of HF admission, with adjusted hazard ratios of 0. 66(95% confidence interval, 0.47-0.94) in the second quartile to 0.47 (95% confidence interval, 0.27-0.82) in the highest quartile. Results were similar when individuals with previously diagnosed HF (2.8%) were excluded or when the analysis was repeated using quartiles of magnesium intake without accounting for body weight. Magnesium intake <2.3 mg/kg was related to increased risk of subsequent HF hospitalizations. Future studies are needed to test whether serum magnesium levels predict risk of HF.