title: Serum ionized magnesium: relation to blood pressure and racial factors.
abstract: To study potential ionic factors predisposing to vascular disease in hypertension, particularly among black subjects, we used a recently developed combined magnesium and calcium specific, ion selective electrode apparatus to measure extracellular ionized calcium (Ca-ion), ionized magnesium (Mg-ion), and Ca-ion/Mg-ion ratios in the serum of fasting, nonmedicated white and black normotensive (n = 61) and hypertensive (n = 23) subjects, studied consecutively in a tertiary referral center. Both race and blood pressure status had independent effects on the distribution of Mg-ion values. Although Mg-ion levels for the group as a whole were lower in hypertensive versus in normotensive subjects (0.571+/-0.012 v 0.601+/-0.005 mmol/L; P < .01), this was only true of white subjects (0.579+/-0.021 v 0.620+/-0.006 mmol/L; P = .0095). The lack of a significant difference in Mg-ion levels between black hypertensive versus normotensive subjects (0.553+/-0.012 v 0.577+/-0.007 mmol/L, P = NS) was attributable to the significantly lower Mg-ion levels present in normotensive blacks compared to those in normotensive white subjects (0.577+/-0.007 v 0.620+/-0.006 mmol/L, P = .0001). Resultant Ca-ion/Mg-ion ratios were elevated in all black subjects and in white hypertensive subjects. These data support the presence among hypertensives and among black subjects (independently of blood pressure) of a consistent depletion of circulating magnesium and of an imbalance of calcium and magnesium that may potentiate vascular disease among these subjects.
authors.affiliation: Cardiovascular Center, New York Hospital-Cornell Medical Center, New York, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Resnick
authors.forename: O
authors.initials: O
authors.lastname: Bardicef
authors.forename: B T
authors.initials: BT
authors.lastname: Altura
authors.forename: M H
authors.initials: MH
authors.lastname: Alderman
authors.forename: B M
authors.initials: BM
authors.lastname: Altura
mesh_terms: D044383:Black People; D001794:Blood Pressure; D002118:Calcium / Q000097:blood; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000208:ethnology; D008274:Magnesium / Q000097:blood*; D008297:Male; D044465:White People
chemical_list: D008274:Magnesium; D002118:Calcium