Nitric oxide (NO) stimulates bone formation and inhibits bone resorption in vitro. NO donors (nitrates) are inexpensive and widely available, but their value for post-menopausal osteoporosis has never been evaluated in a randomized trial. The objective of this study was to compare the effects of 5 and 20 mg of isosorbide mononitrate (ISMO) on markers of bone turnover in post-menopausal women.METHODS
A prospective randomized trial was carried out in the Department of Obstetrics & Gynecology, Ain Shams University, Egypt. The study included 50 healthy post-menopausal women with a hip bone mineral density T score between 0 and −2.5. Participants were randomly assigned to 5 or 20 mg/day of ISMO for 12 weeks. Urine N-telopeptide (NTx), a marker of bone resorption, and serum bone-specific alkaline phosphatase (BSALP), a marker of bone formation, were measured. Markers were measured immediately before randomization and after 12 weeks of treatment. The percent change in NTx and BSALP for each of the treatment groups (5 mg ISMO and 20 mg ISMO) was calculated. The main outcome measures were serum NTx and BSALP in the 5 and 20 mg ISMO groups after 12 weeks of treatment.RESULTS
Women adhering to 20 mg of ISMO had a 42.03% (95% confidence interval (CI), 20.1–73.7) reduction in NTx and a 29.05% (95% CI, 10.8–48.4) increase in BSALP, and women adhering to 5 mg of ISMO had a 31.12% (95% CI, 8.3–68.2) reduction in NTx and a 28.4% (95% CI, 4.6–52.1) increase in BSALP.CONCLUSION
ISMO, as a NO donor, may be useful for the prevention of post-menopausal osteoporosis.