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Appendix D Summary Tables on Epidemiological Studies
Pages 223-298

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From page 223...
... Appendix D Summary Tables on Epidemiological Studies 223
From page 224...
... : 0.14 to 919 mg/m3 Employed at least 1 yr Mean tenure: 7 yrs 109 workers monitored (range 1­25 yrs) for hippuric acid and creatinine in their urine Noise exposure: Continuous noise, 71 to 93 dBA; dosimetry for individual workers
From page 225...
... sig hearing protection associated w/ hearing loss Pure-tone audiometry: (OR = 1.76, 95% CI 0.5­8 kHz 1.00­2.98) continued
From page 226...
... Experimental 33 chinchillas, in 6 10-day exposures (2002) exposure groups Toluene: 2000 ppm 6 adult rats as control Noise: 500 Hz octave group band noise, 97.5 dB SPL Background noise < 60 dBA 22 chinchillas (monaural)
From page 227...
... average of 0.5, 1, 2 1.5­17.5) kHz > 25 dB Other hearing loss Unilateral, conductive Pure-tone audiometry: 0.5­8 kHz Otoscopy, immittance audiometry Differences in liver metabolism of toluene suggest that rats and mice are better models for human ototoxicity than chinchillas Chinchillas Chinchillas ABR threshold shifts Noise effects, but no (pre- vs postexposure)
From page 228...
... Controls: 10 Noise: 10 Noise: 10 h/d, 7 d/w Toluene: 10 Continuously varying Noise followed by signal: 2 kHz wide toluene: 10 noise band, sweeping Noise, rest, toluene: 9 from 3 to 30 kHz at freq of 0.5 Hz Equivalent to sound level of 100 dB Controls: no noise or toluene Noise: 4 wks Toluene: 2 wks Noise followed by toluene: 4 wks noise, 2 wks toluene Noise, rest, toluene: 4 wks noise, 4 wks rest, 2 wks toluene
From page 229...
... APPENDIX D 229 Outcome Measure Results Comments Rats Rats ABR threshold shifts Sig permanent threshold (pre- vs postexposure) shift w/ shorter toluene Tested at 8, 16, 32 kHz exposure Postexposure testing on Threshold shifts of 20 and day 30 15 dB at 16 and 32 kHz, respectively ABR thresholds at 1.6, Effect of noise followed by Additive effects from 3.15, 6.3, 12.5, 20.0 toluene, w/ or w/o rest, noise and toluene kHz was larger than exposure to noise or toluene alone Exposure to toluene after Measured at 1­5 wks at 6.3, 12.5, and 20.0 kHz noise may produce after termination of smaller losses than exposure Noise: higher thresholds exposure to noise after than controls at 6.3 (9 dB, toluene p < .05)
From page 230...
... : 8 signal: 2 kHz wide Group T+N (toluene noise band, sweeping followed by noise) : 9 from 3 to 30 kHz at a freq of 0.5 Hz Equivalent sound level 100 dB Controls: no toluene or noise Group T: 2 wks toluene Group N: 4 wks noise Group T+N: 2 wks toluene; 4 wks noise NOTES: ABR, auditory brainstem response; CI, confidence interval; OR, odds ratio; TWA, time-weighted average.
From page 231...
... ; for most animals, threshold exceeded maximum stimulus intensity at 12.5 and 20.0 kHz For any exposure, threshold shift greatest at 6.3 and 12.5 kHz; after 6 mos, greatest at 12.5 kHz Combined exposure (toluene followed by noise) produced greater shifts at 3.15 (p < .01)
From page 232...
... Background noise: ~ 50 dBA CO only Noise only: 95 dB for 4 h 100 dB for 2 h 105 dB for 1 hr Noise plus CO: 95 dB for 4 h, 100 dB for 2 h 105 dB for 1 hr Control: Air only B: Increased 2 exposure groups: in CO: 1200 ppm duration of each, n = 6 Noise: 105 dB exposure Noise only: 4 h Noise plus CO: 4 h
From page 233...
... APPENDIX D 233 Outcome Measure Results Comments CAP thresholds for 11 Exposure groups Rats more resistant to pure tones between 2 significantly different from CO than humans (30 and 40 kHz each other (F(8, 45)
From page 234...
... (2000) A: Variation of 8 exposure groups: in CO: varied exposures CO dose each, n = 8 Noise: 100 dB octave band noise w/ center Random assignment frequency of 13.6 kHz Background noise: < 35 dB CO only: 1200 ppm, 8 h Noise only: 8 h Noise plus CO (5 exposure groups)
From page 235...
... APPENDIX D 235 Outcome Measure Results Comments CAP thresholds for 11 Noise plus CO pure tones between 2 Potentiation of noise effects and 40 kHz by CO exposure emerges at CO exposures of 500 4-wk recovery period ppm and increases as CO level increases Sig elevation of thresholds over exposure to noise only with exposures to CO levels > 300 ppm Thresholds at lower frequencies affected only w/ CO levels 1200 ppm; CO only No effect on auditory function CAP thresholds for 11 Nonlinear relationship b/t pure tones between 2 noise severity and and 40 kHz potentiation of threshold elevation by CO 4-wk recovery period Potentiation of noise effects by CO exposure greatest w/ noise exposure of 100 dB for 2 h For noise exposure of 100 dB for 4 h, no additional effect at higher freq from CO exposure; sig differences at some lower freq Sig difference from controls for noise exposure of 100 dB for 2 or 4 h, w/ or w/o CO continued
From page 236...
... 236 APPENDIX D TABLE D-2 continued Citation Design Population Exposures C: Repeated 4 exposure groups: in CO level: 1200 ppm exposures each, n = 8 Noise exposure: Octave band noise w/ center Random assignment frequency of 13.6 kHz Exposure duration: 5 successive days: CO only Noise only: 95 dB, 2 h Noise plus CO Control: Air only Chen and Experimental Rats Fechter (1999) A: Response to Exposure groups: CO level: 1200 ppm CO and high- Noise exposure: 8h, frequency vs High-freq noise octave band noise low-frequency CO: n = 4 High freq: 9.6­19.2 kHz noise Noise: n = 7 at 100 dB (Ln)
From page 237...
... ; somewhat greater potentiation at low freq Noise alone produced sig CAP threshold shifts at all freq CO alone produced no CAP threshold shifts CM elevations for noise plus CO over noise alone at all freq, w/ greater differences at low freq; sig differences at only three freq continued
From page 238...
... over time 1 wk Noise: n = 4 Noise plus CO: n = 3 4 wks Noise: n = 7 Noise plus CO: n = 7 Air: n = 7 E: Hearing loss CO level: 0­1500 ppm potentiation Noise: 8 h, 9.6­19.2 kHz and CO at 100 dB (Ln) concentration
From page 239...
... APPENDIX D 239 Outcome Measure Results Comments CAP and CM threshold Noise plus CO: CAP shifts in three freq threshold shifts and CM ranges: elevations greater than Low: 2­8 kHz noise alone, especially at Mid: 12­20 kHz high and mid frequencies, High: 24­40 kHz for 9.6­19.2 kHz and 4.8­ 9.6 kHz bands Noise alone: only 9.6­19.2 kHz noise band caused significant CAP threshold shifts and CM elevations Difference in mean CAP Potentiations shown by CAP or CM between noise and CM are correlated plus CO and noise and similar alone High-frequency noise: measured at freq > 8kHz Low-frequency noise: measured at 2­6 kHz CAP thresholds measured Thresholds sig higher than at 1 wk, 2 wks, and controls for noise plus CO 4 wks after exposure and noise alone at freq > 8 kHz Noise plus CO: No sig difference b/t 1 wk and 4 wks Noise alone: Lower thresholds at 4 wks than at 1 wk; sig differences at 12, 16, 30, 35 kHz; remain sig higher than controls at > 8 kHz Average CAP thresholds Greater potentiation with measured at 2­8 kHz, higher CO levels; CO 12­20 kHz, and 24­40 effect varies across freq kHz ranges Potentiation of hearing loss 4-wk recovery period begins at CO level of 300­ 500 ppm for freq > 8 kHz continued
From page 240...
... 240 APPENDIX D TABLE D-2 continued Citation Design Population Exposures Young et al. Experimental 16 male rats CO: 210 min, 1200 ppm (1987)
From page 241...
... APPENDIX D 241 Outcome Measure Results Comments Reflex modulation CO only: no evidence of CO levels higher than audiometry: detection worse auditory those likely in sensitivity thresholds at functioning after exposure occupational settings 10 and 40 kHz Noise only: worse thresholds Thresholds measured after exposure (p < .01) ; before exposure and at 10 kHz worse than 40 1 wk and 3 wks kHz at 1 wk postexposure Noise plus CO: thresholds worse than noise alone; greater shift at 40 kHz than 10 kHz; sig interaction effect at 1 week (p < .05)
From page 242...
... 242 APPENDIX D TABLE D-3 Smoking as a Risk Factor for Noise-Induced Hearing Loss Exposures and Source Citation Design Population of Exposure Data Ferrite and Cross-sectional 535 male metal plant Questionnaire: socio Santana workers participating demographics, life (2005) in hearing screening style, occupational and and enrolled in health health-related data, promotion program and smoking Northeast Brazil Noise exposure Exclusions: women; age > Based on job-noise matrix: 55 yrs; missing Exposed: jobs w/ 81­93 audiometric data; dBA hearing loss Nonexposed: jobs w/ inconsistent with noise < 81 dBA damage Pre-employment noise exposure assessed Total duration of exposure: 0 < 4 yrs and 4 yrs Smoking Nonsmokers (never smoked or < 6 months)
From page 243...
... Prevalence of hearing loss: Older noise-exposed smokers: 46% Younger noise-exposed smokers: 29% Older nonsmokers not exposed to noise: 24% Younger nonsmokers not exposed to noise: 6% Self-reported hearing Combined exposure to noise Response rate was 58%; difficulties assessed by and smoking was response rate higher response to -- consistent with an additive for women and older "How well can you hear effect subjects a person who is talking No dose-response effect to you when he is Current vs nonsmokers with tested for smoking or sitting on your right moderate to severe hearing noise [left] side in a quiet difficulty Use of hearing protection room?
From page 244...
... Cross-sectional 199 professional forest Questions to establish (1999) workers work history and use 171 shipyard workers of hearing protection, Finland smoking history Medical records Mean age: reviewed, overall Forest workers: 43 yrs health status, Shipyard workers: 38 yrs otological examination Exclusions: hearing loss Noise exposure from ear diseases or A-weighted noise level severe head injuries for average working day for both groups: 100 dB Effective exposure with hearing protectors (measured for each worker)
From page 245...
... Smoking not associated with low-frequency hearing loss Hearing level at 4 kHz Variation in hearing loss All workers exposed to explained (linear noise; differed in noise Measured hearing level regression) levels and duration of compared with exposure expected level (ISO- Forest workers 1999)
From page 246...
... sectional Beaver Dam, Wisconsin, 1993­1995 Noise exposure History of occupational Mean age: 66 yrs noise exposure: having 58% women to speak in a loud voice to be heard; farmer driving tractor w/o cab, or military service with noise (pilot, aircraft or tank crew, ship engine room, use of grenades, mortars, multiperson weapons systems) Smoking status at examination Nonsmoker: < 100 cigarettes (lifetime)
From page 247...
... Significant effect of heavy or moderate and very heavy lifetime nonsmokers Frequencies tested: 0.5, smoking on age-adjusted Non-, moderate, and 1, 2, 3, 4, 6, 8 kHz hearing thresholds: heavy smokers used 3 kHz (right p = .044, left hearing protectors Age adjustment: p = .001) more often (61­64%)
From page 248...
... ) history of vibration syndrome, smoking Exclusions: bilateral ear history disease Complete medical evaluation Noise exposure Time-weighted median inside earmuffs: 99 dBA (91 dBA average inside muffs, 103 dBA outside muffs)
From page 249...
... APPENDIX D 249 Outcome Measure Results Comments Mean hearing threshold Smoking not sig correlated of both ears at 4 kHz with sensorineural hearing loss at 4 kHz Age correction based on A-weighted noise levels and duration of exposure
From page 250...
... History of noise Ages at entry: 60­81 yrs exposure: (mean 68 yrs) 56 of 85 men 18 of 78 women Recruitment through advertisements and referral, began in 1987 Conventional thresholds tested annually Exclusions: conductive hearing loss, active otologic/neurologic disease Longitudinal study of presbyacusis, Medical University of South Carolina
From page 251...
... Rate of change at 6­8 kHz lower for noise-exposed Testing also done for than unexposed males; extended high lower at 2 kHz for noise frequencies exposed females Hearing thresholds at 2­8 kHz were significantly higher (7.7 to 12.1 dB, p < 0.05) for noise-exposed men Noise-exposed women had smaller threshold elevations (2.2 to 7.6 dB)
From page 252...
... 2,800 participants Losses to death, refusal, loss to follow-up; losses greater among persons w/ hearing loss Epidemiology of Hearing Loss Study, Beaver Dam, WI Rosenhall Mixed Gerontological and Questionnaires: (2003) longitudinal geriatric population occupation and and cross- study, Gothenburg, exposure to sectional Sweden occupational noise cohort Total population: 616 men 869 women Cohorts 1.
From page 253...
... Self-reported occupational noise exposure: not significant Progression of hearing Progression of hearing loss loss All: 53.5% (CI 50.2­56.4)
From page 254...
... cohort initial Framingham presence and Heart Study cohort characteristics of with audiometric tests audiometric notch at from examinations E15 Examination E15 and E22 Notch determined from E15 two-part function for No notch (N0) : 75 right linear pattern at ears (RE)
From page 255...
... significantly different; exposure for most (e.g., subjects and little Secondary analysis LE shifts: N0 = 12.4; N1 = recreational exposure included as predictor 16.0; N2 = 18.8; p = variables 0.0018) Past noise exposure cardiovascular disease inferred from presence events (lifetime)
From page 256...
... nal and hearing conserva- (mean age for cross- Data from Air Force tion program personnel at sectional hearing conserva- (8 bases) each test)
From page 257...
... than noise-exposed cushions USAF civilians and % distribution of HTLs general U.S. popu for each frequency lation % STS 0.5, 1, 2, 3, 4, Not specified Mean hearing threshold Total personnel in 6 kHz levels (ears not re- hearing conserva ported separately)
From page 258...
... 258 APPENDIX D TABLE D-5 continued Timing of Data Citation Design Collection Study Population Stratification b. Army Studies Walden et Cross- 1971 2,726 men Age (yrs)
From page 259...
... 50% at 15 yrs before test TDH-39 earphones LOS w/ MX-41/AR Middle to high fre cushions quencies most affected Assigned hearing profile category not correct for many 2, 3, 4, 6 kHz ANSI, 1969 Mean and median Mean thresholds hearing thresholds lower (better) than Grason-Stadler (standard deviation, aviators in Walden audiometer, standard error)
From page 260...
... 1,625 tests Test results from feasibility study for reference audiograms No otologic exami nations
From page 261...
... ences among MOS No information on groups audiometer or Change from reference Better current HTLs earphones thresholds (graphed at 3, 4, and 6 kc/s data only) by 23­34 dB, than 1954 data for comparably aged men working in industry may reflect exclusions for other causes of hearing loss in military population 0.5, 1, 3, 4, 6 Standard hearing Mean hearing thresh- 59% of enlisted kHz conservation olds (average of left combat arms per program and right ears)
From page 262...
... 20­24.9 yrs and periodic 18,730 enlisted men physical examina- from low-noise tions (low-noise exposure MOS MOS) (administration, supply and ser vices, medical, visual informa tion, electronic maintenance and calibration, public affairs, automated data processing, topography, intelligence)
From page 263...
... noise MOS and 18% of personnel Tracor RA 600AM Age correction from in low-noise MOS microprocessor ISO-1999, database B Exposure categories audiometer based on current MOS; no informa TDH-39 earphones tion on noise with ear cushions exposure history No control for nonoc cupational noise Significant difference in average thresh olds between high and low-noise groups, but differ ences were < 5 dB 0.5, 1, 2, 3, 4, ANSI, 1969 "Average" hearing 37% of experimental 6, 8 kHz threshold levels group and 23% of Manual audiometry (standard deviation) control group had significant high-freq No information on % of subjects with hearing losses at audiometer or significant high- and 5 yrs of service earphones low-frequency hear ing losses ( 30 dB)
From page 264...
... 121 recruits 298 women (9% overall: 18% of recruits: 16% of control; 1.7% of experimental) "Subjects were identified by computer" Exclusions: conduc tive hearing loss Goldenberg Cross- 13-month period 11,577 men (Marine Age (yrs)
From page 265...
... Median hearing thresh- Marine Corps data 6 kHz olds (better ear only; similar to USPHS Rudmose ARJ-4A graphed data) for civilians audiometer, 10- Markedly higher man booth % w/ > 25 dB and % thresholds at ages w/ > 45 dB loss at 35­44 yrs and older TDH-39 earphones avg of speech fre quencies (0.5, 1, 2 If questionable self- kHz)
From page 266...
... ; HTL, hearing threshold level; LOS, length of service; MOS, military occupational specialty; NEHC, Navy Environmental Health Center; OSHA, Occupational Safety and Health Administration; STS, significant threshold shift; USPHS, U.S. Public Health Service.
From page 267...
... were generally NEHC guidance worse than OSHA age-adjusted values Women had lower thresholds than men w/in each service at corresponding ages 0.5, 1, 2, 3, 4, ASA, 1951 Median hearing No noise-exposure 6 kcps thresholds history Beltone audiom- (method for calculat- Hearing levels higher eters, TDH-39 ing 95% confidence w/ age from young earphones w/ intervals described) est to oldest MX-41/AR cushions % distribution by hearing threshold Minimum threshold: categories ­10 dB HL
From page 268...
... past yr Higher frequencies: Australia, 1997 PTA for 4, 6, and Residents of 2 8 kHz suburban postal code areas Hearing loss PTA for 0.5, 1, 2, and 4 kHz > 25 dB HL in better ear Pure-tone testing at 0.25, 0.5, 1, 2, 4, 6, 8 kHz (3 kHz if 20 dB differ ence b/t 2 and 4 kHz) Hoffman and Reed Cross-sectional Tinnitus Hearing loss (2004)
From page 269...
... Noise during mili tary service Leisure noise (e.g., gunfire) Questionnaire on 15% w/ tinnitus Odds ratio for Possible response noise exposure tinnitus bias Occupational noise: 25 dB HL Participation rates difficult to have a Men: 1.0 were 65% for conversation; type Women: 1.0 men; 73% for of work; exposed women; < 50% to staple gun, > 25, 40 dB HL for ages < 30 yrs; hammering, chain Men: 2.84 (95% CI 75% for ages saw, blasting, etc; 2.55­3.16)
From page 270...
... longitudinal "buzzing, ringing, PTA of thresholds or noise" in the at 0.5, 1, 2, and 4 Epidemiology of Baseline ears in the past kHz > 25 dB HL Hearing Loss 3,737 participants, year, rated as at in worse ear Study, Beaver ages 48 to 92 least moderately Dam, WI years severe or causing Pure-tone testing at 1993­2000 problems w/ sleep 0.25, 0.5, 1, 2, 3, 5-yr follow-up or both 4, 6, 8 kHz 2,558 participants (75% of those w/o Excludes tinnitus significant tinnitus rated mild or of at baseline) unknown severity and not causing problems w/ sleep Palmer et al., (2002)
From page 271...
... tinnitus loud voice to be Severe: 1.5% heard at 2 ft; Moderate or causing w/o hearing loss - farmer who drove sleep problems: 5% w/ significant tractor w/out cab 6.7% tinnitus at least half of the time; or - military duties on 5-yr Incidence aircraft; tracked 6% [5.7%; 95% CI vehicle, ship 4.8­6.6] engine room; on weapons range 7 times per yr; used grenades, mortars, or shoulder-held grenade launchers; used weapons system requiring more than one operator Questionnaire Persistent tinnitus W/ severe hearing Possible response response on Men: 6% difficulty bias (58% re number of years Women: 3% Men: 16.1% w/ sponse rate)
From page 272...
... household member] have hearing loss Adams and Marano interviews ringing, roaring or (subjective assess (1995)
From page 273...
... APPENDIX D 273 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments No exposure data 3% w/ tinnitus 94% participation rate Age < 45 yrs: 1% 45­64 yrs: 6% 65+ yrs: 9% 18+ yrs: 4% 45+ yrs: 7% 4% w/ tinnitus Moderate or worse Unknown effect of hearing loss exclusion of 32% w/ tinnitus proxy responses on representative Uses hearing aid ness of data 12% w/ tinnitus (40,570 adult proxy responses) No exposure data 8% w/ tinnitus Moderate or worse Unknown effect of hearing loss exclusion of 42% w/ tinnitus proxy responses on representative ness of data (27,364 proxy responses)
From page 274...
... 274 APPENDIX D TABLE D-6 continued Definition of Definition Hearing Level or Study Design, Population of Tinnitus Hearing Loss Coles (1996) Cross-sectional Prolonged spontane- Hearing threshold ous tinnitus: levels Tier B, National 3,234 people se- lasting at least 5 Study of Hearing, lected in stratified minutes and not United Kingdom random sample temporarily in from postal sur- duced by noise, vey responses drugs, or ear or respiratory illness Stratification to ensure larger proportion of persons w/hearing disorders and tinnitus Medical Research Cross-sectional Prolonged spontane Council's Institute (multiple samples)
From page 275...
... APPENDIX D 275 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments Presence of moder- Controlling for ately or severely hearing thresholds annoying tinnitus eliminates associa tions w/ age, HTL 10­19 dB vs noise exposure, or HTL < 10 dB socioeconomic OR=2 status HTL >80 dB vs HTL < 10 dB OR= 27 Little or no occupa- Prolonged, 80% response rate tional noise expo- spontaneous sure: 8% w/ 10% 7% of all adults tinnitus have sought a Any tinnitus doctor's help for High lifetime noise 34% to 39% tinnitus dose: 21% w/ tinnitus Brief or nonspontaneous 23% to 27% Spontaneous 11% to 18% Moderately or severely annoying: 5% Sleep-disturbing: 5% Severe effect on quality of life: 1% Severe effect on ability to lead a normal life: 0.5% continued
From page 276...
... 276 APPENDIX D TABLE D-6 continued Definition of Definition Hearing Level or Study Design, Population of Tinnitus Hearing Loss Phase II "Nowadays" noises lasting 5 minutes or more, exclud ing those occur ring only after exposure to loud noise Parving et al.
From page 277...
... APPENDIX D 277 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments 17% w/ tinnitus Significantly higher prevalence of tinnitus if hearing affected (X2, p < 0.001) Hearing affected: Yes: 27% w/ tinnitus No: 11% w/ tinnitus Continuous tinnitus F01 Age 70: 8% Age 75: 12% Age 79: 11% F06 Age 70: 12% Occasional tinnitus F01 Age 70: 20% Age 75: 17% Age 80: 30% F06 Age 70: 19% continued
From page 278...
... - normal 2,378 responses (never/seldom/ - some hearing loss Gothenburg, from adults, ages often/always) - marked hearing Sweden, 1980s 20­79 yrs loss Additional character- - deaf Postal survey using ization of tinnitus age-stratified only for those random sample responding "often" from city popula- or "always" tion register Roberts (1968)
From page 279...
... APPENDIX D 279 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments Tinnitus Response rate: 66% Always: 6% (usable responses) Often: 8% Seldom/never: 86% No exposure data 32% w/ tinnitus W/ better than normal hearing Severe: 6% 3% w/ tinnitus Mild: 27% W/ some hearing impairment 22% w/ tinnitus continued
From page 280...
... Exclusions: ear disease or pre employment noise exposure Griest and Bishop Longitudinal Tinnitus reported at Annual audiograms (1996) (retrospective annual audiogram starting in 1971 cohort)
From page 281...
... APPENDIX D 281 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments Noise survey; 0.34 Noise-exposed impulses per 70% w/ tinnitus second Controls Hearing protectors 4% w/ tinnitus not worn regularly Noise levels: TWA Tinnitus reports at Tinnitus at baseline of 85 to 101 dBA audiograms not excluded Never: 62% Exposure of 85 1­2 times: 17% For 20- to 29-yr dBA for 10 yrs or 3+ times: 20% olds at baseline, more no significant Tinnitus reports on differences beSound surveys and questionnaire tween those dosimetry from 2 Never: 39% reporting any to 4 hour expo- Rarely / several tinnitus and no sures times a month: tinnitus in mili 43% tary, recreational, Hearing protection Several times a week or other occupa use recorded or more: 17% tional noise exposure Significant associa tion between frequency of tinnitus reports at audiogram and report of tinnitus several times a week or more in questionnaire (X2, p < 0.0001) continued
From page 282...
... "Do you ever hearing loss 38,725 otologically have ringing Age-corrected "perWestern Australia normal, noise- noises .
From page 283...
... 30% Once a day or Prevalence signifi more: 34% cantly lower in < once a week: 39% early hearing loss cases than inter Excluded cases mediate and 42% w/ tinnitus late cases (X2, p = 0.02) continued
From page 284...
... " tion programs programs (instruction to interviewers: Exclusions: history tinnitus present of ear disease, more than mo head injury, ear mentarily and at surgery, relative least recurring if w/ hereditary not continuous) hearing loss; current day-to-day changes in hear ing, ruptured ear drum
From page 285...
... , or shooting Reports on shooting history after history controlling for hearing thresholds continued
From page 286...
... (2002) Cross-sectional Do you experience Noise-induced or hear sounds hearing loss Israel 2,200 male soldiers when no sound Average threshold at source appears to 2­8 kHz 25 dB Random selection of be present?
From page 287...
... APPENDIX D 287 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments Interview to deter- 14% w/ tinnitus Normal hearing mine previous 3% w/ tinnitus noise exposure Hearing loss 19% w/ tinnitus Questionnaire to Continuous tinnitus: Normal hearing Data on other noise establish exposure 9% 2% continuous exposure may be to weapons fire Occasional tinnitus: tinnitus incomplete 34% 33% occasional tinnitus Correlations: Number of weapons Slight/moderate loss impulses: r = 3% continuous 0.27, p < 0.001 31% occasional Small-caliber weap ons: r = 0.26, Severe loss p < 0.001 20% continuous Large-caliber weap- 32% occasional ons: r = 0.1, p < 0.005 Disabling loss Frequent use of 26% continuous hearing protec- 43% occasional tors: r = ­0.17, p < 0.001 Questionnaire on 17% w/ "annoyance Possible recall bias type of service, of tinnitus" in link between previous impulse tinnitus and noise exposure, Ever exposed to exposure to heavy use of hearing heavy detonations: detonations protectors Yes: 26% w/ tinnitus No: 5% w/ tinnitus Sound pressure (X2, p < 0.001) levels for weapons measured at Age (yrs)
From page 288...
... Cross-sectional No questions/ Acute acoustic (1999) definition trauma: acute 81 male acoustic provided acoustic exposure Austrian military trauma patients producing tempo service, Jan 1995­ Mean age: 22 yrs rary or permanent June 1996 pure-tone thresh Treated 3 days after old shift exposure Hearing loss: Exclusions: hearing threshold > 20 dB threshold > 20 dB HL HL at any fre quency at start of Hearing thresholds service; illnesses, at 0.125­8 kHz conditions that might affect auditory system
From page 289...
... Perceived problems Other exposure 33% tinnitus worse history from than hearing loss medical records 33% hearing loss worse than tinnitus 80% not wearing 84% w/ tinnitus Hearing loss No significant hearing protection 83% w/ tinnitus differences for: (accidental dis- No hearing loss a. blank/live ammu charges, loss of 100% w/ tinnitus nition protectors, etc.)
From page 290...
... Cross-sectional and No definition Acute acoustic (1976) longitudinal provided trauma: abrupt onset of sympIsrael, 1967­1970 433 soldiers treated toms (tinnitus or for acute acoustic hearing loss)
From page 291...
... No ear protection 61% (of ears) w/ Normal Some hearing loss used tinnitus 42% may have existed Mild AT before acoustic Change in subjective 60% trauma symptoms (includ- Moderate AT Lower initial sever ing tinnitus)
From page 292...
... dB HL only at exposed to gunfire frequencies above or blast 2 kcps III: thresholds > 60 basis for selection dB HL above 2 not specified kcps or elevated at 0.5 to 2 kcps IV: thresholds elevated at 0.5 to 1 kcps Pure-tone testing at 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, kc/ sec NOTE: AT, acoustic trauma; CI, confidence interval; NIHL, noise-induced hearing loss; OR, odds ratio; PTA, pure-tone average; TWA, time-weighted average.
From page 293...
... APPENDIX D 293 Noise Exposure Prevalence of and Source of Prevalence Tinnitus, by Exposure Data of Tinnitus Hearing Level Comments Noise levels mea- No overall preva- Prevalence of sured under field lence reported tinnitus conditions Normal: 15.7% I: 33% No estimate of II: 25% rounds fired by III: 35% individuals IV: 56% Prevalence of tinni tus after firing Normal: 41% I: 49% II: 49% III: 57% IV: 64%
From page 294...
... 2005. Joint effects of smoking, noise exposure and age on hearing loss.
From page 295...
... U.S. Navy and Marine Corps hearing conservation program, 1995­1999: Mean hearing thresholds for enlisted personnel by gender and age groups.
From page 296...
... 1978. Current Hearing Threshold Levels for Noise-Exposed U.S.
From page 297...
... 1996. Evaluation of tinnitus and occupational hearing loss based on 20-year longitudinal data.
From page 298...
... 1999. Tinnitus and impulse noise-induced hearing loss in drop-forge operators.


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