Table 1.

Studies that considered blood copper levels.

First Author, Year	Study Design	Institution and Country	Inclusion Criteria	Number of Subjects (M-F) Mean Age	Micronutrient Serum Concentration Osteoporosis	Micronutrient Serum Concentration Osteopenia	Micronutrient Serum Concentration Normal	Primary Outcomes	Results
Okyay E, 2013 [25]	Cross-sectional study	Dokuz Eylul University School of Medicine, Izmir, Turkey	Postmenopausal women between age 45 and 80	728 F 56.52 ± 6.14 y	Women at 45–59 years: (p value < 0.05) Cu (μg/mL): -L1–L4 osteoporotic (OP) 96.6 ± 39 -Total femur OP 90 ± 37.5 -Femoral neck OP 96.3 ± 33.9		Women at 45–59 years: (p value < 0.05) CU (μg/mL): -L1–L4 non OP 112.6 ± 28.2 -Total femur non OP 111.3 ± 30.2 -Femoral neck non OP 111.4 ± 30.9	Relationship between serum main minerals and postmenopausal osteoporosis.	Low Cu serum levels were independent risk factors for development of OP especially in early menopausal period.
Mutlu M, 2007 [26]	Cross-sectional study	Erciyes University, Kayseri, Turkey	Post-menopausal women	120 F 40 OP 58 ± 8.40 y, osteopenic 57 ± 9 y and 40 healthy group 59 ± 6 y	Cu (mg/L) 1.54 ± 0.12	Cu (mg/L) 1.59 ± 0.09	Cu (mg/L) 1.60 ± 0.08	Cu changes in osteoporotic, osteopenic, and normal postmenopausal women.	No statistically significant differences observed between the osteopenic, osteoporotic, and control groups with respect to copper levels.
Arikan DC 2011 [27]	Case–control study	Medical Faculty of Kahramanmaras Sutcu Imam (Kahramanmaras, Turkey)	Natural menopause for more than 6 months	107 F 35 healthy 48.17 ± 7.78 y, 37 osteopenic 55.32 ± 7.78 y and 35 OP 60.57 ± 8.65 y	Cu (μg/dL) 138.76 ± 37.21	Cu (μg/dL) 137.58 ± 31.73	Cu (μg/dL) 140.92 ± 32.74	Serum Cu levels in postmenopausal women with osteoporosis, osteopenia, and in healthy controls, and the relationship between Cu and bone mineral density (BMD).	Plasma levels of all parameters were similar across each group (p > 0.05).
Mahdavi-Roshan, 2015 [28]	Cross-sectional study	Rheumatology clinic in Tabriz, Islamic Republic of Iran	women > 50 years old postmenopausal, having no history of hormone replacement therapy	51 F 57.97 ± 1.2 y		Serum Cu (μg/dL): 27.29 ± 1.26	Serum Cu (μg/dL) 26.75 ± 1.35	Investigate and compare the mineral status between osteopenic and osteoporotic postmenopausal women.	No statistically significant differences between the osteopenic and osteoporotic groups with respect to serum levels of Cu.
LIU SZ, 2009 [29]	Cross- sectional study	Xi’an urban area, China	45 to 65-year-old females in natural and no hormone drug intake and osteoporosis treatment 6 months before investigation	290 F 54.4 ± 5.5 y	Cu serum (mg/L) 0.8873 ± 0.2930	Cu serum (mg/L) 0.8528 ± 0.2397	Cu serum (mg/L) 0.8498 ± 0.3106	Correlation between serum macroelement and trace element contents and BMD as well as the occurrence of osteoporosis.	There exist significant correlations between the contents of serum Cu, but no significant differences in this element content between the osteoporosis group, osteopenia group, and healthy group.