Vitamin B12 injection may not improve vocal performance in singers: JAMA
Israel: Empirical vitamin B12 injection did not do much in improving mild voice-related symptoms in singers, according to a recent study in the journal JAMA Otolaryngology–Head & Neck Surgery. The study found no meaningful difference in self-reported voice measures in singers with vitamin B12 injection compared to placebo.
About one-third of singers and vocal professionals have reportedly benefited from empirical vitamin B12 injections for improving mild singing-related symptoms (eg, reduced stamina, vocal fatigue, and effort). However, there is absence of evidence to either support or refute the claims. To fill this knowledge gap, Hagit Shoffel-Havakuk, Department of Otolaryngology–Head and Neck Surgery, Rabin Medical Center, Petach Tikva, Israel, and colleagues assessed the presence and magnitude of the effect of empirical vitamin B12 injection on the vocal performance of singers.
For the purpose, the researchers conducted a randomized, double-blind, placebo-controlled, crossover trial from November 7, 2017, to November 30, 2018, at an academic voice center among 20 active adult singers without dysphonia but with mild vocal symptoms. The study excluded patients with known or suspected vitamin B12 deficiency or active or recent vitamin B12 treatment.
The 20 participants were randomized to receive an intramuscular (deltoid) injection of either vitamin B12 (1000 μg of cyanocobalmin) or placebo (0.9% sodium chloride). After a washout period of at least 4 weeks, participants were crossed over to receive the opposite injection. Both the investigators and participants were blinded to the order of injections.
The participants completed the Singing Voice Handicap Index–10 (SVHI-10), the Voice Fatigue Index (VFI), and the Evaluation of the Ability to Sing Easily (EASE) before each injection and at intervals of 1 hour, 3 hours, 24 hours, 72 hours, and 1 week after the injection. The primary time point assessment was 72 hours after injection,and the SVHI-10 score was the primary outcome measure.
Key findings of the study include:
- The improvements after either placebo or vitamin B12 injections were comparable to each other.
- At 72 hours after the vitamin B12 injection, the median difference in the SVHI-10 score was 1 compared with 3 after placebo.
- The median difference between differences at 72 hours between placebo and vitamin B12 injections were 1.5 for the SVHI-10, 1 for the VFI, and –1 for the EASE.
- The improvements after both injections failed to reach the estimated minimal clinically important difference.
- Of the 20 participants, 4 (20%) reached the estimated minimal clinically important difference in their SVHI-10 score after 72 hours for both vitamin B12 and placebo injections.
"This randomized, double-blind, placebo-controlled, crossover trial found that after empirical vitamin B12 injection to improve mild voice-related symptoms, the improvement in self-reported voice measures in singers shows no meaningful difference compared with placebo. It is therefore recommended that vitamin B12 should not be given empirically to improve the vocal performance of singers and voice professionals," concluded the authors.
The study, "Effect of Vitamin B12 Injection on Vocal Performance of Professional Singers," is published in the journal JAMA Otolaryngology–Head & Neck Surgery.