Clinical trial NCT00552786: Antioxidation Medication for Noise-induced Hearing Loss
Official title: Antioxidation Medication for Noise-induced Hearing Loss
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Hearing Loss
Keywords: noise
hearing loss
temporary threshold shift
Lead sponsor: National Taiwan University Hospital
Sponsor class: OTHER
Collaborators: name: Institute of Occupational Safety and Health, Taiwan
name: Municipal Hospital of Tainan, Taiwan
First posted: 2007-11-02
Enrollment: 53
Sex: MALE
Minimum age (years): 25
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: PREVENTION

Brief summary: This study will examine whether oral intake of 1200mg N-Acetylcysteine/day will prevent temporary threshold shift in hearing among workers exposed to noise

Detailed description: Both genetic and environmental factors contribute to noise-induced hearing loss (NIHL). The cellular antioxidant system appears to protect cochlear hair cells from oxidative stress due to noise. Previous animal studies showed protective effects of anti-oxidant medicines against NIHL.The objective of this study is to test the hypothesis that preventive medication of antioxidation is related to susceptibility to NIHL.

The 53 noise-exposed workers from steel industries in Taiwan will be recruited, and divided into N-Acetylcysteine (NAC)(Acetine, 1200mg/day) group and placebo one. The duration of medication is 2 weeks initially. After washout for 2 weeks, the kinds of medications in these 2 groups will be crossover and used for 2 weeks. Firstly, questionnaires interview about noise exposure, smoking, alcohol drinking, drug habit history and calculation of Body Mass Index (BMI) will be done. The following methods would be performed individually after medication. With detailed local examination with otoscope, these subjects receive hearing tests by pure-tone audiometry (PTA) and distortion product otoacoustic emissions (DPOAE) before and after their daily works. The possible confounding factors including background noise, solvent, heavy metals, carbon monoxide and temperature in the workplaces will be assessed. The amount of noise exposure is evaluated by personal dosimeter. Early morning, Blood samples will be collected. Deletion polymorphisms in the Glutathione S-transferase (GST)T1 and GSTM1 genes will be determined. Statistical analysis will be performed to evaluate the relation between intake of anti-oxidant medicine and noise-induced temporal threshold shift (TTS).

The expected results of this study are to determine whether anti-oxidant supplements protect workers from noise-induced TTS.

We anticipate that these human studies might help elucidate the relative importance of anti-oxidant enzymes as risk factors for NIHL.

Eligibility criteria: Inclusion Criteria:

* workers in steel industry
* known exposure to noise at work

Exclusion Criteria:

* ever diagnosed as having diabetes mellitus
* fasting glucose of 120 or greater

Primary outcomes:
measure: Temporary Threshold Shift Measurement by Pure Tone Audiometry (A Total of Four Hearing Assessments Were Completed for Each Formulation Period on the 1st Day Pre- and Post-shift, and the 14th Day Pre- and Post-shift)
timeFrame: A total of four hearing assessments were completed for each formulation period on the 1st day pre- and post-shift, and the 14th day pre- and post-shift
Secondary outcomes:
measure: Temporary Threshold Changes Measurement by Distortion Product Otoacoustic Emissions (DPOAE) (A Total of Four Hearing Assessments Were Completed for Each Formulation Period on the 1st Day Pre- and Post-shift, and the 14th Day Pre- and Post-shift)
timeFrame: A total of four hearing assessments were completed for each formulation period on the 1st day pre- and post-shift, and the 14th day pre- and post-shift
Other outcomes:
Locations:
city: Taipei
country: Taiwan
facility: Environmental and Occupational Medicine, National Taiwan University Hospital
Study officials:
affiliation: National Taiwan University Hospital
name: Yue-Liang L Guo, MD, MPH, PHD
role: PRINCIPAL_INVESTIGATOR
affiliation: Institute of Occupational Safety and Health, Taiwan
name: Tung-Sheng Shih, PHD
role: STUDY_DIRECTOR
References:
citation: Coleman JK, Kopke RD, Liu J, Ge X, Harper EA, Jones GE, Cater TL, Jackson RL. Pharmacological rescue of noise induced hearing loss using N-acetylcysteine and acetyl-L-carnitine. Hear Res. 2007 Apr;226(1-2):104-13. doi: 10.1016/j.heares.2006.08.008. Epub 2006 Oct 4.
citation: Kopke R, Bielefeld E, Liu J, Zheng J, Jackson R, Henderson D, Coleman JK. Prevention of impulse noise-induced hearing loss with antioxidants. Acta Otolaryngol. 2005 Mar;125(3):235-43. doi: 10.1080/00016480410023038.
citation: Duan M, Qiu J, Laurell G, Olofsson A, Counter SA, Borg E. Dose and time-dependent protection of the antioxidant N-L-acetylcysteine against impulse noise trauma. Hear Res. 2004 Jun;192(1-2):1-9. doi: 10.1016/j.heares.2004.02.005.
citation: Kopke RD, Jackson RL, Coleman JK, Liu J, Bielefeld EC, Balough BJ. NAC for noise: from the bench top to the clinic. Hear Res. 2007 Apr;226(1-2):114-25. doi: 10.1016/j.heares.2006.10.008. Epub 2006 Dec 20.
citation: Lin CY, Wu JL, Shih TS, Tsai PJ, Sun YM, Ma MC, Guo YL. N-Acetyl-cysteine against noise-induced temporary threshold shift in male workers. Hear Res. 2010 Oct 1;269(1-2):42-7. doi: 10.1016/j.heares.2010.07.005. Epub 2010 Jul 16.