Vitamin D deficiency can lead to low BMD and an increased risk of falls and OVCF [13]. Although the effect of vitamin D supplementation on the rate of OVCF have been investigated in studies [14], no study has investigated the effects of vitamin D supplementation after the onset of OVCF. A benign natural history has long been assumed for OVCFs, but up to 30% of symptomatic patients who seek treatment do not respond well to nonsurgical treatment [15, 16]. Cooper et al. reported that patient population studies suggest a positive correlation between mortality rate and number of involved vertebrae in patients with OVCF [17]. Once OVCF is diagnosed, nonsurgical management with activity modification and symptomatic medication, with or without bracing, is adequate for most patients [18], but the primary goal of OVCF management is early pain control and improvement of functional outcome.
According to a study by Barton et al., only 14% of patients who visited the emergency room for OVCF claimed to take calcium and vitamin D supplementation before their incident OVCF [2]. It was also reported that 9% of patients without prior supplementation had received vitamin D supplementation 1 year after OVCF. The study also reported that 75% of patients with incident vertebral fracture did not receive calcium and vitamin D supplementation at any time during the study [2].
Calcium and vitamin D supplementation remains a mainstay in the treatment and prevention of osteoporosis [18]. It is important in the treatment of patients with osteoporosis and deficiency of calcium and vitamin D. Vitamin D is known to play an important role in the immune system and bone health of patients with OVCF [19]. According to Kroner et al., immune cells are regulated by 1, 25-hydroxyvitamin D (1,25(OH)D), and immune cells metabolically participate in the production of 1,25(OH)D from serum 25(OH)D [20]. This highlights the importance of vitamin D in shaping immune response. Vitamin D is even considered a hormone rather than a vitamin because vitamin D and its receptor are found on the surface of many other cells [21].
In many clinical trials of anti-osteoporosis drugs, vitamin D and/or calcium supplementation is administered to study participants to improve the efficacy of the anti-osteoporosis drugs [22–26]. However, there is no consensus on the appropriate dose of vitamin D and calcium, but it varies from 0 to 1200 IU/day for vitamin D and from 200 to 1500 mg/day for calcium [22–26]. This dose range is appropriate for fracture prevention, but the appropriate dose after OVCF and the underlying mechanism are unknown. In this study, we aimed to determine the effect of vitamin D after OVCF. In the patient group that received supplementation of vitamin D (at least 400 IU/day) and calcium (at least 600 mg/day), the baseline sufficiency status of 25(OH)D in the blood was associated with the effect of Denosumab on BMD and fracture prevention. The study by Sugimoto et al. showed that Denosumab, which was used as a prophylactic drug for osteoporosis, did not affect the baseline vitamin D status [27].
The limitations of this study are presented below. First, the biggest drawback is that the sample size is little statistical significant. Although there is a group of 65 patients each, the statistical evidence for 65 patients is insufficient, it is believed that better results can be obtained if additional large-sample studies are conducted. Second, in this study, we planned vitamin D supplementation based on random extraction from the initial vitamin D deficiency group; however, we did not find relevant previous studies. Therefore, we decided to conduct a pilot study. If a randomized double-blind study based on this study is conducted in the future, more accurate results can be expected. Third, the follow-up period of 12 months is short, and there was limited information on long-term results when the baseline sufficiency status of vitamin D was maintained. In conclusion, fracture union was achieved in all patients regardless of 25(OH)D level, and there were significant improvements in severity of LBP, functional outcome, and QoL over 12 months in patients with OVCF. Short-term vitamin D supplementation of patients with OVCF and deficiency of 25(OH)D did not result in significant differences in fracture union status, functional outcome, and QoL between the S groups and NS groups of patients. Based on the results of this study, the effects of vitamin D supplementation in patients with OVCF will be more clearly observed in a study with a larger sample size and a longer follow-up period.