Serum ionized magnesium and calcium in women after menopause: inverse relation of estrogen with ionized magnesium

Abstract

Objective: To study the serum concentrations of the sex steroid hormones and free divalent cations Mg 2+ and Ca 2+ in healthy women at or past menopause and to compare them with the serum concentrations of healthy, cycling women of child-bearing age at different stages of the menstrual cycle. Design: Controlled clinical study. Setting: An academic medical center. Patient(s): Women of varying age and duration of menopause, and healthy, cycling women. Intervention(s): None. Main Outcome Measure(s): Serum levels of the sex steroids (estrogen, progesterone, and testosterone) and of Ca 2+ and Mg 2+ were measured in menopausal and postmenopausal women, and in healthy, cycling women at five different stages of the menstrual cycle. Result(s): The Mg 2+ and total Mg levels of the postmenopausal women were inversely related to the serum level of estrogen and were similar to the levels present during the early follicular phase of healthy women of child-bearing age. The Ca 2+ level was unrelated to the sex steroid hormones present, but it was increased compared with that of younger women in both the follicular phase and the luteal phase. Conclusion(s): Serum levels of Mg 2+ and total Mg were inversely correlated with the estrogen concentration in menopausal women. Serum levels of Ca 2+ were significantly elevated in menopausal women compared with younger women, but the ratio of Ca 2+ to Mg 2+, a measure of cardiovascular problems, was not elevated in the postmenopausal women.