Comparison of Magnesium Status Using 24-h Urine Magnesium Content and Magnesium Fraction Excretion in PCOS with Non-PCOS Control Women: a Cross-sectional Study

Magnesium (Mg) is the second most frequent intracellular cation, having an important role in normal enzyme function and insulin secretion. Polycystic ovarian syndrome (PCOS) is the most prevalent endocrinopathy in women of reproductive age and often associated with insulin resistance. Two systematic reviews and meta-analyses have been conducted to compare mean serum Mg levels between PCOS and control groups. Both studies detected unexplained heterogeneity among input studies and the two conclusions contradict each other, while approximately 1% of total body Mg is present in extracellular fluid (ECF) and serum Mg level does not represent Mg status well. For the first time, we investigated magnesium renal fraction excretion (FEMg) and compared mean values between PCOS and non-PCOS control women. This study is a cross-sectional analysis conducted at an academic medical center. Forty-four women were included in the PCOS group based on the Rotterdam criteria and 50 non-PCOS women were included in the control group. Statistical analysis of the relationship between 24-h urinary Mg content and FEMg, and also physical and metabolic variables, was performed. Main outcome measurements are 24-h urinary Mg content and FEMg. Mean values of 24-h urinary Mg content and FEMg did not significantly differ between PCOS and control groups (P = 0.22 and P = 0.24, respectively). Also, serum Mg levels and Ca/Mg ratio were similar between the groups (P = 0.17 and P = 0.26, respectively). Our data suggested Mg status in the PCOS group was similar to the non-PCOS control group and both were not magnesium deficient. For further investigation, we recommend using FEMg for evaluating Mg status rather than serum Mg levels. Considering collection of background diet is helpful and desired for future studies.