Vitamin D + Calcium Fracture Prevention Study Results

meta-analysis PMID: 31860103

Quick Summary: A large study looked at whether taking vitamin D and calcium helps prevent broken bones. The results showed that these supplements don't significantly reduce fracture risk for most people, but may help those in nursing homes.

What The Research Found

The study found that taking vitamin D and calcium supplements didn't significantly lower the risk of broken hips or other fractures in people living in the community. However, there was a small benefit for people living in nursing homes, with a 16% reduction in hip fractures.

Study Details

Who was studied: Over 53,000 adults aged 50 and older, both those living at home and in nursing homes.

How long: The studies followed people for 1 to 7 years.

What they took: Participants took vitamin D, with or without calcium, in various doses, or a placebo (a dummy pill). Vitamin D doses ranged from 400 to 7000 IU/day.

What This Means For You

If you live at home, this study suggests that taking vitamin D and calcium supplements may not prevent fractures. However, if you live in a nursing home, these supplements might help reduce your risk of a broken hip. Talk to your doctor to see if these supplements are right for you.

Study Limitations

The study combined results from many different studies, and the results varied. Also, most people in the studies already had enough vitamin D. The study couldn't always tell if the vitamin D or the calcium (or both) were helping.

Key Findings

This meta-analysis concluded that vitamin D combined with calcium supplementation did not significantly reduce hip fracture risk in the general adult population (RR 0.97, 95% CI 0.86–1.10; p=0.64). A statistically significant 16% reduction in hip fractures was observed only in institutionalized older adults (RR 0.84, 95% CI 0.74–0.96; p=0.01). No significant benefit was found for non-vertebral or total fractures across community-dwelling populations. The study determined that routine supplementation for fracture prevention in the general population lacks strong evidence.

Study Design

This systematic review and meta-analysis synthesized data from 81 randomized clinical trials (RCTs) involving 53,537 participants. Trials compared vitamin D (with or without calcium) against placebo/no treatment. Participants were primarily community-dwelling and institutionalized adults aged ≥50 years, with a mean age range of 65–81 years across studies. Follow-up durations varied from 1 to 7 years. The analysis used random-effects models to pool risk ratios (RRs) for fracture outcomes.

Dosage & Administration

Vitamin D doses ranged from 400 to 7000 IU/day, administered daily, weekly, or monthly. Calcium doses (when co-administered) ranged from 500 to 1200 mg/day, typically as calcium carbonate or citrate. Most trials used daily dosing regimens. The analysis specifically examined dose-response relationships and found no consistent benefit across different vitamin D dose levels in community settings.

Results & Efficacy

For hip fractures in community-dwelling adults, vitamin D ± calcium showed no significant effect (RR 0.97, 95% CI 0.86–1.10; p=0.64). In institutionalized settings, hip fracture risk was significantly reduced (RR 0.84, 95% CI 0.74–0.96; p=0.01). Non-vertebral fracture risk was not significantly reduced overall (RR 0.96, 95% CI 0.88–1.04; p=0.30). Subgroup analyses revealed no dose-dependent efficacy; even high-dose regimens (≥800 IU/day) failed to show consistent benefits in community populations.

Limitations

Significant heterogeneity existed across trials (I²=66% for hip fractures), reflecting variations in dosing, participant demographics, and baseline vitamin D status. Most participants had sufficient baseline vitamin D levels (mean baseline 25(OH)D >20 ng/mL), limiting generalizability to deficient populations. Individual participant data were unavailable, preventing adjustment for confounders like fall risk or adherence. Publication bias could not be fully excluded. The analysis could not isolate vitamin D effects from calcium co-administration in most trials.

Clinical Relevance

This study indicates that routine vitamin D and calcium supplementation is not justified for fracture prevention in community-dwelling adults, regardless of dose. Clinicians should prioritize targeted supplementation only for institutionalized older adults or individuals with confirmed vitamin D deficiency (<12 ng/mL). For the general population, resources are better allocated toward proven interventions like fall prevention, adequate protein intake, and weight-bearing exercise. Patients should consult healthcare providers for personalized assessment rather than self-supplementing based on age alone.