Table 1.

Studies that considered blood magnesium levels

First author, year	Study design	Setting	Inclusion criteria	Exclusion criteria	Number of subjects (M-F) Mean age	Primary outcomes
Mederle et al. (2018)	Case–control study	Outpatient Department of Endocrinology of the CountyHospital,Timisoara	Women in the postmenopausal period, with lumbar or femoral neck BMD, expressed as T-score,2.5 standard deviation (SD). The control group included women in the postmenopausal period, with lumbar or femoral neck T-score. − 2 SD	Secondary causes of osteoporosis, other diseases that could influence the bone metabolism or electrolyte imbalance (especially Mg), fractures in the previous year, hormone replacement therapy, and any medication that could influence bone turnover	213 F(132 cases–81 controls)	Determine the correlations between BMD and serum levels of bone resorption markers (TRAP-5b), bone formation markers (BSAP), estradiol (E2), and Mg(2 +) ion concentrations in postmenopausal osteoporotic women as compared to healthy postmenopausal subjects
Okyay et al. (2013)	Obesrvational study	Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology at DokuzEylulUniversitySchoolof Medicine,Izmir, Turkey	Postmenopausal women between age 45 and 80 y	History of drug abuse or alcohol consumption (to drink at least ≥ 2 days per week), and highly intake of caffeinated coffee (> 2 cups per day), laboratory tests or radiography of any bone metabolism disorder	728 F	Determine the relationship between serum main minerals and postmenopausal osteoporosis
Mahdavi et al. (2015)	Observational study	Rheumatology clinic in Tabriz, Islamic Republic of Iran,	Women > 50 years old who had been no menstruation for ≥ 6 months prior to entry into the study, having no history of hormone replacement therapy, other bone disease, kidney stones, endocrine disorders or any medical conditions that could influence on the mineral status	Use of mineral supplements, having history of hormone replacement therapy, bone disease, kidney stones, endocrine disorders or any medical conditions that could influence on the mineral status	51 F(23 had osteoporosis and 28 had osteopenia)	Investigate and compare the copper, magnesium, zinc and calcium status between osteopenic and osteoporotic postmenopausal women in Tabriz, Islamic Republic of Iran
Hayhoe et al. (2015)	Case Cohort Longitudinal Study	Norfolk, UK	Men and women aged 40–82 y living in the general community	–	2328 ultrasound cohort group – 4713 fracture case-cohort group	The influence of dietary magnesium and potassium intakes, as well as circulating magnesium, on bone density status and fracture risk in an adult population in theUnited Kingdom
Sharma et al. (2016)	Observational study	TSMMedical College & Hospital, Lucknow,Uttar Pradesh, India	Postmenopausal women with 48 to 75 years	–	68 F(33 with osteoporosis and 35 with osteopenia)	The role of magnesium in osteoporosis and in osteopenia
Kunutsor et al. (2017)	Prospective cohort study	Eastern Finland	Men aged 42–61 years (a cohort of the Kuopio Ischemic Heart Disease Prospective Study) living in the city of Kuopio and its neighbouring rural communities	–	2245 M	Investigate the association of baseline serum magnesium concentrations with risk of incident fractures
Rai (2016)	Observational study	OPD Dept of Orthopedics, TSM Medical College & Hospital, Lucknow, India	Postmenopausal women 48–75 years	–	68 F(33 with osteoporosis and 35 with osteopenia)	Evaluation of magnesium role in bone homeostasis, especially in postmenopausal women with osteopenia and osteoporosis
Huang et al. (2015)	Cross-sectional study	Hospital clinic of Central Taiwan	CKD patients not receiving dialysis	–	56 (27 with Diabetes and 29 without Diabetes)	Investigate the impact of serum Mg on bone mineral metabolism in chronic kidney disease (CKD) patients with or without diabetes
Elshal et al. (2012)	Case–control study	Outpatient clinic of the university hospital of	Adults with an age range 20–40 years with sickle-cell anaemia in steady-state and race-matched healthy blood donors	Use of steroids, had anorexia nervosa, hyperthyroidism, chronic obstructive pulmonary disease, liver disease, inflammatory bowel disease, or had deranged renal functions (serum creatinine > 2.5 mg/dl)	60 with sickle-cell anaemia (34 F – 26 M) and 40 healthy blood donors as controls (22 F – 18 M)	Investigate whether serum Mg levels may have an impact on bone mineral density in sickle-cell anaemia

First author, year	Micronutrient serum concentration osteoporosis	Micronutrient serum concentration osteopenia	Micronutrient serum concentration normal	Micronutrient serum reference value	% subjects < reference value	Results
Mederle et al. (2018)	1.76 ± 0.06 mg/dl	2.14 ± 0.14 mg/dl	–	1.6–2.4 mg/dL	–	Osteoporotic patients showed significantly lower concentrations of serum Mg(2 +) than the control group. Mg(2 +) levels correlated positively with BMD values (r = 0.747, P,0.0001)
Okyay et al. (2013)	45–59 y: 0.86 ± 0.1 mg/dl (osteo L1-L4), 0.84 ± 0.16 mg/dl (osteo total femur), 0.86 ± 0.18 mg/dl (osteo femoral neck)—60–80 years: 0.85 ± 0.1 mg/dl (osteo L1-L4), 0.85 ± 0.14 mg/dl (osteo total femur), 0.86 ± 0.16 mg/dl (osteo femoral neck)	–	45–59 y: 0.89 ± 0.1 mg/dl (non osteo L1-L4), 0.89 ± 0.17 mg/dl (non osteo total femur), 0.89 ± 0.16 mg/dl (non osteo femoral neck)—60–80 years: 0.94 ± 0.1 mg/dl (non osteo L1-L4), 0.91 ± 0.18 mg/dl (non osteo total femur), 0.91 ± 0.17 mg/dl (non osteo femoral neck)	–	45–59 y: 47,1%—52,9% (osteo – non osteo L1-L4)/29,4%—70,6% (osteo – non osteo total femur)/32,4%—67,6% (osteo – non osteo femur neck)	Low serum magnesium levels had significant association with osteoporosis of L1–L4 spines and total femur
Mahdavi et al. (2015)	0.76 ± 0.02 mmol/l	0.77 ± 0.01 mmol/l	–	–	40,4%	40.4% of patients had serum magnesium level lower than normal range
Hayhoe et al. (2015)	–	–	–	0.7–1.0 mmol/l	–	Statistically significant trends in fracture risk in men across serum magnesium concentration groups were apparent for spine fractures (P = 0.02) and total hip, spine, and wrist fractures (P = 0.02)
Sharma et al. (2016)	1.95 ± 0.44 mg/dl	2.22 ± 0.42 mg/dl	–	1.9–2.5 mg/dl	–	The serum concentration of magnesium was lower in osteoporosis group and the result was statistically significant (< 0.05)
Kunutsor et al. (2017)	–	–	–	1.8–2.3 mg/dl	6% of subject with fractures	Low serum magnesium is strongly and independently associated with an increased risk of fractures
Rai (2016)	1.95 ± 0.44 mg/dl	2.22 ± 0.42 mg/dl		–	–	The serum concentration of magnesium (1.95 ± 0.44 vs. 2.22 ± 0.42) was lower in osteoporosis group, and the result was statistically significant (< 0.05)
Huang et al. (2015)	–	–	–	1.82–2.31 mg/dl	10,7%	The lower serum Mg subgroup showed a higher incidence of osteoporosis than the moderate and higher serum Mg subgroups did (66.7%, 39.4%, and 29.4%, resp.)
Elshal et al. (2012)	–	–	–	0.7–1.2 mmol/l	33,3% of subjects with sickle-cell anaemia	The serum magnesium was found to be associated positively with serum calcium (Ca), PTH and Osteocalcin (r = 0.585; r = 0.436; r = 0.351 respectively, all at p < 0.05), and negatively with PO4 (r = –0.312; p < 0.05). Hypo-Magnesium patients had significantly lower BMD and T-score at all evaluated sites (L2, L4, and WB) than norm-Magnesium patients and controls (all p < 0.05)