Prevention of benign paroxysmal positional vertigo with vitamin D supplementation: A randomized trial.
Level 2 - randomized trial
Individual randomized controlled trial with blinded outcome assessment
PubMed 32759193 · doi:10.1212/WNL.0000000000010343
What was done
An investigator-initiated, multicenter, blinded-outcome assessor randomized controlled trial across 8 hospitals evaluated 1,050 patients with confirmed benign paroxysmal positional vertigo (BPPV) after successful canalith repositioning maneuvers. Participants were assigned to an intervention group (n = 518) or an observation group (n = 532). In the intervention arm, participants with baseline serum vitamin D < 20 ng/mL took 400 IU of vitamin D and 500 mg of calcium carbonate twice daily for 1 year. The observation arm received follow-up without vitamin D testing or supplementation. The primary outcome was the annual recurrence rate (ARR) over 1 year.
What was found
Intention-to-treat analysis demonstrated a lower ARR in the intervention group compared to observation: 0.83 (95% CI, 0.74 to 0.92) versus 1.10 (95% CI, 1.00 to 1.19) recurrences per person-year (incidence rate ratio 0.76, 95% CI, 0.66 to 0.87, p < 0.001; absolute rate ratio -0.27, 95% CI, -0.40 to -0.14). Recurrence occurred in 37.8% of intervention patients compared to 46.7% of observation patients (p = 0.005), corresponding to a number needed to treat of 3.70 (95% CI, 2.50 to 7.14).
Why it matters
Supplementing vitamin D and calcium in patients with subnormal serum vitamin D provides an accessible, non-invasive strategy to lower the rate of BPPV recurrences after repositioning maneuvers.
Limits
The study was open-label for participants (no placebo control) with only outcome assessment blinded. The observation group did not undergo baseline vitamin D testing, and the combined regimen prevents distinguishing whether vitamin D, calcium, or their combination drove the benefit.
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- context Loose otolith calcium crystals in the inner ear that cause dizziness can be treated with vitamin D and K2.