Oral magnesium supplementation as prophylaxis for noise-induced hearing loss: results of a double blind field study.
Level 2 - randomized trial
Individual double-blind randomized controlled trial
What was done
A double-blind, placebo-controlled field trial evaluated 320 voluntary military recruits with verified normal hearing during a 2-month training period. Participants received a drink containing either 4 g magnesium granulate (6.7 mmol magnesium aspartate) or placebo on each working day. Subjects were exposed to firearm noise (mean 420 shots per person, mean peak level 164 dB(A)) while wearing earplugs with 25 dB insertion loss. Serum, erythrocyte, and lymphocyte magnesium levels were measured before and after training. Audiograms were measured 7 days after the last noise exposure to determine permanent threshold shifts (PTS).
What was found
Serum and erythrocyte magnesium concentrations increased over time in both groups, whereas lymphocyte magnesium increased only in the magnesium group. Following noise exposure, the percentage of ears showing a PTS > 25 dB at 4 kHz, 6 kHz, and/or 8 kHz was twice as high in the placebo group as in the magnesium group. Exact percentages, counts, and p-values were not provided in the abstract.
Why it matters
This study provides randomized trial evidence that oral magnesium supplementation can provide prophylactic protection against acoustic trauma from high-intensity impulse noise.
Limits
The abstract does not report raw counts, exact percentages, standard errors, or statistical significance tests. The findings in young military recruits exposed to protected firearm impulse noise may not generalize to continuous occupational noise or other populations. Audiometric follow-up was limited to 7 days post-exposure.
Cited by
- supports Clinical trials in military recruits undergoing mandatory service showed that prophylactic magnesium supplementation reduced noise-induced hearing loss from weapons exposure.