Micronutrients to Prevent Noise-induced Hearing Loss
Condition: Noise-Induced Hearing Loss
MeSH terms: Hearing Loss; Deafness; Hearing Loss, Noise-Induced
Intervention: beta-carotene, vitamins C and E, magnesium; Placebo
Intervention description: 6 mint-flavored tablets per day, taken once daily
total daily dose label claim: micronutrient combination of 500 mg vitamin C (magnesium ascorbate), 315 mg magnesium (magnesium citrate, magnesium ascorbate, magnesium stearate), 267 mg vitamin E (d-α-tocopherol acetate), and 18 mg beta carotene.; 6 mint-flavored tablets per day, containing inactive substances including mannitol, peppermint flavor, sucralose, color prep, iron oxide yellow synthetic, stearic acid (vegetable grade), and silicon dioxide colloidal.
Intervention MeSH terms: Beta Carotene; Carotenoids
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 72.0
Sex: All
Minimum age: 18 Years
Maximum age: 35 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: Noise; Hearing Loss; Tinnitus; Antioxidant; Vasodilator; Beta-Carotene; Vitamin C; Vitamin E; Magnesium

Summary:

      Noise-induced hearing loss (NIHL) is a significant clinical, social, and economic issue.
      Studies in animals have allowed us to identify mechanisms contributing to NIHL, including
      direct mechanical trauma, free radicals formed in association with metabolic stress, and
      reduced blood flow. A combination of antioxidant vitamins (beta-carotene, and vitamins C and
      E) and the mineral magnesium (which acts in part as a vasodilator but also as an antioxidant)
      is highly effective in preventing NIHL in animals. These studies evaluate efficacy of this
      intervention in humans.

      Hypothesis: Treatment with these micronutrients provides safe, effective attenuation of acute
      hearing changes induced by exposure to real-world sounds producing temporary (non-permanent)
      or permanent hearing changes induced by exposure to real-world sounds.

      Experiment 1: "Digital Audio Player" studies (University of Florida, Gainesville). Prevention
      of *temporary* elevations in hearing thresholds, induced by exposure to moderately loud
      music, will be measured. Subjects will be 70 young adults with equal numbers of male and
      female participants.
    

Eligibility criteria:

        Inclusion Criteria:

        Hearing inclusion criteria are as follows for all studies:

          -  subjects must have a normal audiologic assessment at baseline consisting of:

               1. symmetric hearing with air conduction thresholds no worse than 25 dB HL at tested
                  frequencies between .25 - 8 kHz;

               2. no significant threshold asymmetry (i.e., greater than 15 dB) between the ears at
                  any test frequency;

               3. no significant air-bone gaps (i.e., greater than 10 dB); and

               4. Type A tympanograms bilaterally, defined as a range of -140 to +40 daPa based on
                  the 90% range for adults (Margolis & Hunter 2000).

        Additional criteria are as follows:

          -  No history of ear disease, able to provide informed consent, agree to follow study
             procedures, normal health screening at study entry

        Exclusion Criteria:

          -  Pregnant or trying to become pregnant within study period (females)

          -  subjects belonging to vulnerable populations

          -  subjects with any history of chronic disease

          -  hearing loss that exceeds limits specified above

          -  inability or failure to provide informed consent

          -  medical conditions that require treatment with drugs including anticoagulants

          -  diuretics

          -  digoxin

          -  aspirin/salicylate

          -  barbiturates

          -  minocycline