Lower Plasma Magnesium Levels Research Articles

Drug use is associated with lower plasma magnesium levels in geriatric outpatients; possible clinical relevance

Hypomagnesemia has been associated with diabetes, cardiovascular disease, and other disorders. Drug use has been suggested as one of the risk factors for low magnesium (Mg) levels. In the elderly population, prone to polypharmacy and inadequate Mg intake, hypomagnesemia might be relevant. Therefore, we aimed to investigate associations between drug use and plasma Mg. Cross-sectional data of 343 Dutch geriatric outpatients were analysed by Cox and linear regression, while adjusting for covariates. Drug groups were coded according to the Anatomical Therapeutic Chemical classification system; use was compared to non-use. Hypomagnesemia was defined as plasma Mg<0.75mmol/l and <0.70mmol/l. Prevalence of hypomagnesemia was 22.2% (Mg<0.75mmol/l) or 12.2% (Mg<0.70mmol/l); 67.6% of the patients used ≥5 medications (polypharmacy). The number of different drugs used was inversely linearly associated with Mg level (beta-0.01; p<0.01). Fully adjusted Cox regression showed significant associations of polypharmacy with hypomagnesemia (Mg<0.75mmol/l) (prevalence ratio (PR) 1.81; 95%CI 1.08-3.14), proton pump inhibitors (PR 1.80; 95%CI 1.20-2.72), and metformin (PR 2.34; 95%CI 1.56-3.50). Moreover, stratified analyses pointed towards associations with calcium supplements (PR 2.26; 95%CI 1.20-4.26), insulins (PR 3.88; 95%CI 2.19-6.86), vitamin K antagonists (PR 2.01; 95%CI 1.05-3.85), statins (PR 2.44; 95%CI 1.31-4.56), and bisphosphonates (PR 2.97; 95%CI 1.65-5.36) in patients <80 years; selective beta blockers (PR 2.01; 95%CI 1.19-3.40) if BMI <27.0kg/m2; and adrenergic inhalants in male users (PR 3.62; 95%CI 1.73-7.56). Linear regression supported these associations. As polypharmacy and several medications are associated with hypomagnesemia, Mg merits more attention, particularly in diabetes, cardiovascular disease, and in side-effects of proton pump inhibitors and calcium supplements.

The influence of dietary phosphorus and magnesium concentrations on the calcium content of heart and kidneys of DBA/2 and NMRI mice.

Dystrophic cardiac calcification (DCC) is often found in DBA/2 mice, reportedly in association with low plasma magnesium levels in this mouse strain. It was hypothesized that high-phosphorus diets and low-magnesium diets that are known to lower plasma magnesium concentrations would promote the development of DCC. DBA/2 mice were fed diets with either low-magnesium (0.02%, w/w) or high-phosphorus (0.8%) concentrations or a combination of the two variables. NMRI mice were given either a low- (0.2%) or high- (0.6%) phosphorus diet. Female, but not male, NMRI mice accumulated calcium in the heart when fed the high-phosphorus diet; neither gender developed kidney calcification. DBA/2 mice with either a low-magnesium or a high-phosphorus intake developed marked cardiac calcifications. The combination of low-magnesium and high-phosphorus intake caused severe calcification of the heart, kidney and tongue. Increasing the dietary magnesium content (0.08%) and reducing phosphorus (0.2%) did not fully prevent cardiac calcification, but reduced heart calcium concentrations in male DBA/2 mice. It is concluded that diets for DCC-susceptible mice should contain adequate amounts of magnesium and low, but sufficient amounts of phosphorus in order not to additionally stimulate cardiac calcification.

EFFECT OF SUPPLEMENTAL RATION ON CHANGES IN BLOOD COMPONENTS OF STEERS GIVEN ACCESS TO LUSH PASTURE

Prepasture feeding of low quality hay versus hay and grain had no subsequent effect on rumen fluid ammonia, blood urea, or plasma calcium, glucose and lactic acid concentration in steers turned out on lush pasture. Steers previously fed hay and grain had lower plasma magnesium levels on the first day on unsupplemented pasture than those fed hay prior to pasture. Supplemental feed on pasture partly alleviated the depression in plasma magnesium on the first day on pasture. Feeding supplemental hay with pasture tended to lower rumen fluid ammonia, blood urea and plasma lactic acid compared with feeding no supplement during the initial days on pasture, indicating the desirability of hay feeding during this time. A hay and grain supplement with pasture had a similar effect to the hay supplement on rumen-fluid ammonia, and plasma lactic acid, but a lesser effect on blood urea concentration. Neither supplemental hay nor hay plus grain affected plasma calcium or glucose levels. All steers showed an increase in rumen fluid ammonia, blood urea and plasma lactic acid on the first day and a decrease in plasma calcium and magnesium on the second day on pasture. Blood urea, plasma magnesium and plasma calcium concentrations had not returned to prepasture levels by 21 days on pasture.