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Hormone replacement therapy increases serum 1,25-dihydroxyvitamin D: A 2-year prospective study
H J van Hoof1, M J van der Mooren, L M Swinkels
1Department of Experimental and Chemical Endocrinology, University Hospital Nijmegen St. Radboud, The Netherlands.
Calcified Tissue International
|December 1, 1994
Summary
Hormone replacement therapy (HRT) significantly increases 1,25-dihydroxyvitamin D levels in postmenopausal women. This elevation, sustained for two years, may contribute to HRT
Area of Science:
- Endocrinology
- Bone Metabolism
- Reproductive Medicine
Background:
- Osteoporosis is prevalent in postmenopausal women due to diminished ovarian function.
- Hormone replacement therapy (HRT) is a common treatment to mitigate bone resorption.
Purpose of the Study:
- To investigate the impact of HRT on serum 1,25-dihydroxyvitamin D levels in postmenopausal women.
- To assess the duration of HRT's effect on vitamin D metabolism.
Main Methods:
- A study involving 23 postmenopausal women receiving HRT (17 beta-estradiol and dydrogesterone).
- Serum 1,25-dihydroxyvitamin D concentrations were measured at baseline and at 6, 12, and 24 months.
- Statistical analysis compared baseline levels with levels during HRT.
Main Results:
- Mean serum 1,25-dihydroxyvitamin D concentrations increased significantly from baseline during HRT.
- Elevated levels were observed throughout the 24-month study period.
- No significant difference in 1,25-dihydroxyvitamin D levels was found between estrogen-only and combined estrogen-progestogen phases.
Conclusions:
- HRT leads to a sustained increase in serum 1,25-dihydroxyvitamin D concentration for at least two years.
- This effect may partially explain the osteoporosis-preventive benefits of HRT.
- Dydrogesterone does not appear to alter estrogen-induced changes in 1,25-dihydroxyvitamin D levels.
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