A Phase 2 interventional study of N-acetylcysteine (NAC) and glucose in Hearing Loss, sponsored by National Taiwan University Hospital. Completed at 1 site in Taiwan. Open to male participants aged 25 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2010-07-27.
Sponsored by National Taiwan University Hospital · Phase 2, Interventional, and Prevention
This study will examine whether oral intake of 1200mg N-Acetylcysteine/day will prevent temporary threshold shift in hearing among workers exposed to noise
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.
1,092 studies on the registry are indexed under Hearing Loss; 235 are open to participants now.
This study's enrollment of 53 is above the median of 40 across 764 interventional studies indexed under Hearing Loss.
Browse Hearing Loss studies →National Taiwan University Hospital is the lead sponsor of 2,563 studies on the registry; 569 are open to participants now.
Of its 11 completed or terminated interventional studies of FDA-regulated products, 2 (18%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Drug: N-acetylcysteine (NAC)
Drug: glucose
600mg twice daily for 2 weeks
Also known as: acetin (600mg)
1 gm glucose capsule
Also known as: Sugar
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)
The hearing threshold level (HL) at high frequency (HF) by pure-tone audiometry (PTA) was defined as the average of HLs at 3k,4k,6kHz for each ear examined. A total of four hearing assessments by PTA were completed for each formulation period on the 1st day pre- and post-shift, and the 14th day pre- and post-shift. The amount of temporary threshold change was calculated by subtracting the pre-shift hearing threshold from the post-shift hearing threshold at each frequency.
Time frame: 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
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)
Distortion product otoacoustic emissions (DPOAE) is an objective measure to assess the cochlear changes. DPOAE response threshold at high frequency (HF) was defined as the average of response levels (dB SPL) at 3k,4k,6kHz for each ear examined. A total of four hearing assessments by DPOAE were completed for each formulation period on the 1st day pre- and post-shift, and the 14th day pre- and post-shift. The amount of DPOAE temporary threshold change was calculated by subtracting the pre-shift DPOAE response threshold from the post-shift DPOAE response threshold at each frequency.
Time frame: 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
Participants recruited between November 2007 and January 2008.
| Milestone | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) |
|---|---|---|
| Started | 25 | 28 |
| Medication and hearing evaluation | 25 | 28 |
| Completed | 25 | 28 |
| Not completed | 0 | 0 |
| Milestone | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) |
|---|---|---|
| Started | 25 | 28 |
| Completed | 25 | 28 |
| Not completed | 0 | 0 |
| Milestone | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) |
|---|---|---|
| Started | 25 | 28 |
| Completed | 25 | 28 |
| Not completed | 0 | 0 |
The hearing threshold level (HL) at high frequency (HF) by pure-tone audiometry (PTA) was defined as the average of HLs at 3k,4k,6kHz for each ear examined. A total of four hearing assessments by PTA were completed for each formulation period on the 1st day pre- and post-shift, and the 14th day pre- and post-shift. The amount of temporary threshold change was calculated by subtracting the pre-shift hearing threshold from the post-shift hearing threshold at each frequency.
| decibels | N-acetylcysteine (NAC) | Placebo |
|---|---|---|
| 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) | 3.4 ± 2.3 | 2.7 ± 2.1 |
Distortion product otoacoustic emissions (DPOAE) is an objective measure to assess the cochlear changes. DPOAE response threshold at high frequency (HF) was defined as the average of response levels (dB SPL) at 3k,4k,6kHz for each ear examined. A total of four hearing assessments by DPOAE were completed for each formulation period on the 1st day pre- and post-shift, and the 14th day pre- and post-shift. The amount of DPOAE temporary threshold change was calculated by subtracting the pre-shift DPOAE response threshold from the post-shift DPOAE response threshold at each frequency.
| decibels (dB SPL) | N-acetylcysteine (NAC) | Placebo |
|---|---|---|
| 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) | -0.85 ± 1.1 | -0.89 ± 0.9 |
Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| N-acetylcysteine (NAC) | — | 0/53 (0%) | 0/53 (0%) |
| Placebo | — | 0/53 (0%) | 0/53 (0%) |
| Age, Categorical(Participants) | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) | Total |
|---|---|---|---|
| <=18 years | 0 | 0 | 0.0 |
| Between 18 and 65 years | 25 | 28 | 53.0 |
| >=65 years | 0 | 0 | 0.0 |
| Age Continuous(years) | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) | Total |
|---|---|---|---|
| Mean | 40.0 ± 11.6 | 42.1 ± 9.6 | 41.1 ± 10.5 |
| Sex: Female, Male(Participants) | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) | Total |
|---|---|---|---|
| Female | 0 | 0 | 0.0 |
| Male | 25 | 28 | 53.0 |
| Region of Enrollment(participants) | N-acetylcysteine (NAC) First, Then Placebo | Placebo First, Then N-acetylcysteine (NAC) | Total |
|---|---|---|---|
| Taiwan | 25 | 28 | 53.0 |
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National Taiwan University Hospital