Several clinical trials have reported beneficial effects of organic nitrates on bone health, which could lead to a reduced risk of fractures. Some of these trials have been retracted because of scientific misconduct; however, a study found that organic nitrates do not have clinically relevant effects on bone mineral density or bone turnover in post-menopausal women, and the medications caused significant side effects.
The study was a double-blind, randomised, placebo-controlled trial of three different nitrate preparations and two different doses in postmenopausal women with bone loss. There were no differences in changes in bone mineral density or bone turnover markers between organic nitrate treatment and placebo.
The results call into question the validity of previous clinical research reporting large positive effects of nitrates on bone health.
“Based on previous clinical trials, we had high hopes that treatment with nitrates might be a safe and highly effective treatment for preventing age-related bone loss and fractures. We assessed several different doses and forms of nitrates and our results show clearly that no preparation or dose had any effect on bone density or bone turnover, but they did cause significant side-effects for women,” said lead author Dr Mark Bolland, of the University of Auckland, in New Zealand. “Sadly, this research area has recently had several studies with strongly positive results retracted because of scientific misconduct. We think our paper provides closure, with fairly definitive evidence that nitrates do not affect surrogate measures of bone health and thus there is no reason to think they would prevent fractures.”
Organic nitrates have been reported to have significant effects on bone mineral density (BMD) and bone turnover in previous clinical trials. However, results are inconsistent and some trials with strikingly positive results have been retracted because of scientific misconduct. As preparation for a potential fracture prevention study, we set out to determine the lowest effective dose and the most effective and acceptable nitrate preparation. We undertook a 1‐year, double‐blind, randomized, placebo‐controlled trial of three different nitrate preparations and two different doses in osteopenic postmenopausal women, with a planned 1‐year observational extension. The primary endpoint was change in BMD at the lumbar spine, and secondary endpoints included BMD changes at other sites, changes in bone turnover markers, and adverse events. A total of 240 eligible women who tolerated low‐dose oral nitrate treatment in a 2‐week run‐in period were randomized to five different treatment groups or placebo. Over 12 months, there were no statistically significant between‐group differences in changes in BMD at any site and no consistent differences in bone turnover markers. When the active treatment groups were pooled, there were also no differences in changes in BMD or bone turnover markers between nitrate treatment and placebo. Eighty‐eight (27%) women withdrew during the run‐in phase, with the majority because of nitrate‐induced headache, and 41 of 200 (21%) women randomized to nitrate treatment withdrew or stopped study medication during the 1‐year study compared with 1 of 40 (2.5%) in the placebo group. In summary, organic nitrates do not have clinically relevant effects on BMD or bone turnover in postmenopausal women and were poorly tolerated. These results call into question the validity of previous clinical research reporting large positive effects of nitrates on BMD and bone turnover.
Mark J Bolland, Meaghan E House, Anne M Horne, Veronica Pinel, Greg D Gamble, Andrew Grey, Ian R Reid