Vitamin D supplements do not prevent bone loss in multiple sclerosis patients who are not vitamin-D-deficient, a study reports.

The research, published in the journal BMC Neurology, was titled “High dose vitamin D supplementation does not affect biochemical bone markers in multiple sclerosis – a randomized controlled trial.”

Previous research has suggested that low levels of vitamin D increase the risk of a person developing MS. In addition, Vitamin D prevents loss of bone density. That loss can lead to fractures and osteoporosis, a condition that many MS patients experience as their disease progresses.

“Although the role of vitamin D supplementation on disease activity in MS is unclear, several authors have suggested that vitamin D should be monitored to prevent osteoporosis and fractures,” the researchers wrote. There has been “limited evidence on the effect of vitamin D supplementation on bone health in MS,” however, the team wrote.

Researchers decided to investigate the effect of weekly doses of vitamin D3 on patients with relapsing-remitting multiple sclerosis, versus patients receiving a placebo. All 68 participants in the Phase 4 clinical trial (NCT00785473) also received 500 mg a day of  calcium, a compound that is also important for bone health.

The team measured the effectiveness of the supplemental vitamin D by analyzing biomarkers of bone health in blood. These included levels of the proteins PINP, or procollagen type I N propeptide, and CTX1, or C-terminal cross-linking telopeptide.

At the start of the study, levels of PINP and CTX1 were not significantly different between the two groups. And that continued to be true at week 48 and week 96 of the study.

The bottom line was that vitamin D supplementation did not change bone health in patients with MS after 96 weeks.

“Our results do not support that high dose weekly vitamin D supplementation is beneficial for bone health in ambulatory persons with MS, and suggest that weekly vitamin D supplementation alone is not sufficient to prevent bone loss in persons with MS who are not vitamin D deficient,” researchers concluded.

The results were different from previous studies supporting the beneficial effects of vitamin D supplementation in MS patients. The researchers said they believed the discrepancy was due to differences in the studies’ patient characteristics, sample size, and duration of follow-up.

“This does not exclude that particular subgroups with increased risk of osteoporosis due to immobilization, inadequate nutrition, medication or disease may need vitamin D supplementation to maintain bone health,” the team wrote. “Our study population had rather low disease activity and their ambulation was only moderately impaired. MS patients with more advanced disability are more prone to both accelerated bone loss and vitamin D deficiency, and could benefit more from vitamin D supplementation than those included in this study.”