***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Objective : A revised hearing conservation program ( HCP ) was implemented in the Swedish Armed Forces in 2002 . The aim of this study was to evaluate the incidence of significant threshold shifts ( STS ) in male conscripts heavily exposed to noise after the implementation of the new HCP  , comparing the results to those of an earlier study from 1999/2000 . Design : The study was prospect i ve and longitudinal , covering the period from reporting to military service to discharge . The outcome measure was the incidence of STS . Statistics from the military insurance system was analysed . Study Sample : A total of 395 conscripts were included in the study ( mean age 19 years ) . The control group ( n : 839 ) consisted of men of the same age . Results : In 2004/2005 the incidence rate of STS was 2.3 % compared to 7.9 % in 1999/2000 and compared to 3.7 % among the controls . The number of cases of auditory complications reported from conscripts to the insurance system has decreased , from 16 to 5/100 000 days of military training , during the last decade . Conclusions : The new HCP apparently reduced the incidence rate of STS to one third compared to before the program was introduced and leveled it to the incidence rate in the control-group not exposed to military noise OBJECTIVES ( 1 ) To conduct a contemporary analysis of historical data on short-term efficacy of a 3-year hearing conservation program conducted from 1992 to 1996 in Wisconsin , USA , with 753 high school students actively involved in farm work ; ( 2 ) to establish procedures for assessment of hearing loss for use in a recently funded follow-up of this same hearing conservation program cohort . METHODS We analyzed a pragmatic cluster-r and omized controlled trial , with schools as the unit of r and omization . Thirty-four rural schools were recruited and r and omized to intervention or control . The intervention included classroom instruction , distribution of hearing protection devices , direct mailings , noise level assessment s , and yearly audiometric testing . The control group received the audiometric testing . RESULTS Students exposed to the hearing conservation program reported more frequent use of hearing protection devices , but there was no evidence of reduced levels of noise-induced hearing loss ( NIHL ) . CONCLUSION Our analysis suggests that , since NIHL is cumulative , a 3-year study was likely not long enough to evaluate the efficacy of this intervention . While improvements in reported use of hearing protection devices were noted , the lasting impact of these behaviors is unknown and the finding merits corroboration by longer term objective hearing tests . A follow-up study of the cohort has recently been started OBJECTIVES To address questions surrounding noise-induced hearing loss ( NIHL ) from variable noise , we have been evaluating noise exposures and changes in hearing in a prospect i ve cohort of construction workers ( representing eight trades ) and controls . In this paper , we develop and explore several long-term exposure estimates for cohort members . METHODS We followed cohort members between 1999 and 2009 and interviewed them approximately annually to obtain a detailed work history for the previous subject-interval while also collecting tests of hearing sensitivity . Over the same period , we also collected a sample of full-shift average noise measurements and activity information . We used data from these two sources to develop various exposure estimates for each subject for specific subject intervals and for the duration of the study . These estimates included work duration , trade-mean (TM)-equivalent continuous exposure level ( L(EQ ) ) , task-based ( TB ) L(EQ ) , a hybrid L(EQ ) combining TB and subjective information , and an estimate of noise exposure ' peakiness ' . RESULTS Of the 456 subjects enrolled in the study , 333 had at least 2 interviews and met several inclusion criteria related to hearing sensitivity . Depending on the metric used , between one-third and three-quarters of 1310 measured full-shift noise exposures exceeded permissible and recommended exposure limits . Hybrid and TB exposure estimates demonstrated much greater variability than TM estimates . Work duration and estimates of exposure peakiness showed poor agreement with average exposures , suggesting that these metrics evaluate different aspects of exposure and may have different predictive value for estimating NIHL . CONCLUSIONS Construction workers in the cohort had subject-interval and study -average exposures which present a substantial potential risk of NIHL . In a subsequent paper , we will use these estimates to evaluate the exposure-response relationship between noise and NIHL BACKGROUND Noise-induced hearing loss ( NIHL ) is one of the most common occupational diseases and the second most common cause of workers ' cl aims for occupational injuries . OBJECTIVE Due to high prevalence of NIHL and several reports of improper use of hearing protective devices ( HPDs ) , we conducted this study to compare the effect of face-to-face training in effective use of earplugs with appropriate NRR to overprotection of workers by using earplugs with higher than necessary noise reduction rating ( NRR ) . METHODS In a r and omized clinical trial , 150 workers referred to occupational medicine clinic were r and omly allocated to three arms --- a group wearing earplugs with an NRR of 25 with no training in appropriate use of the device ; a group wearing earplugs with an NRR of 25 with training ; another group wearing earplugs with an NRR of 30 , with no training .  Hearing threshold was measured in the study groups by real ear attenuation at threshold ( REAT ) method . This trial is registered with Australian New Zeal and clinical trials Registry , number ACTRN00363175 . RESULTS The mean ± SD age of the participants was 28 ± 5 ( range : 19 - 39 ) years . 42 % of participants were female .  The mean noise attenuation in the group with training was 13.88 dB , significantly higher than those observed in other groups . The highest attenuation was observed in high frequencies ( 4 , 6 , and 8 kHz ) in the group with training . CONCLUSION Training in appropriate use of earplugs significantly affects the efficacy of earplugs --- even more than using an earplug with higher NRR The CONSORT ( Consoli date d St and ards of Reporting Trials ) Statement , including a checklist and a flow diagram , was developed to help authors improve their reporting of r and omized controlled trials . Its primary focus was on individually r and omized trials with 2 parallel groups that assess the possible superiority of one treatment compared with another but is now being extended to other trial design s. Noninferiority and equivalence trials have method ological features that differ from superiority trials and present particular difficulties in design , conduct , analysis , and interpretation . Although the rationale for such trials occurs frequently , those design ed and described specifically as noninferiority or equivalence trials appear less commonly in the medical literature . The quality of reporting of those that are published is often inadequate . In this article , we present an adapted CONSORT checklist  for reporting noninferiority and equivalence trials and provide illustrative examples and explanations for those items amended from the original CONSORT checklist . The intent is to improve reporting of noninferiority and equivalence trials , enabling readers to assess the validity of their results and conclusions OBJECTIVES The study was done to determine whether the noise attenuation attained with the use of earplugs can be improved by teaching the proper insertion of earplugs to users . METHODS Fifty-four r and omly selected male subjects were divided into an untrained group ( 25 persons ) and a trained group ( 29 persons ) . The trained group was given a lecture on earplug insertion and allowed to practise the insertion procedure , whereas the untrained group acted as controls . The untrained group received this training afterwards . The success of the training was measured by the  MIRE ( microphone in real ear )  and REAT ( real ear at threshold ) methods , visual evaluation and an analysis of the properties of the subjects ' ear canals . RESULTS According to the MIRE method , the averaged A-weighted noise attenuation was 21 dB for the untrained group and 31 dB for the trained group . With the REAT method the attenuation at 1000 Hz was 24 dB for the untrained group and 30 dB for the trained group . The visual evaluation of the earplug fit was 1.9 for the untrained group and 2.6 for the trained group ( scales 0 - 3 ) . CONCLUSION The results indicate that training in earplug insertion is important for good attenuation and for diminishing poor attenuation to a minimum BACKGROUND Prophylactic strategies to counter acquired hearing impairment may involve routine audiometric screening of asymptomatic working-age adults attending general practice for regular health checks . AIM To evaluate the effect of adult hearing screening on subsequent noise exposure and hearing . DESIGN OF STUDY A r and omised controlled population -based study of health checks and health discussion s in general practice . SETTING The project was initiated in the district of Ebeltoft , Aarhus county , Denmark . METHOD Intervention group participants '  hearing thresholds were determined audiometrically at 0.5 , 1 , 2 , 3 , and 4 kHz in each ear . Participants were advised to get their ears checked if the average hearing loss exceeded 20 dB hearing level ( dBHL ) in either ear . Noise avoidance was emphasised when thresholds exceeded 25 dBHL bilaterally at 4 kHz . Follow-up included question naires and audiometry . RESULTS Hearing loss was observed among 18.9 % of the study sample at baseline . At the five-year follow-up we recorded no significant differences between the control and the intervention groups regarding subjective or objective hearing , or exposure to occupational noise . However , there was a tendency towards reduction in exposure to leisure noise among intervention participants ( P = 0.045 ) . Approximately 20 % reported hearing problems ; 16.5 % reported tinnitus-related complaints ; 0.8 % used hearing aids ; 35.0 % reported frequent noise exposure ; and occluding wax was suspected in 2.1 % . CONCLUSION Preventive health checks with audiometry did not significantly affect hearing , but leisure noise exposure tended to become less frequent . The poor effect may be ascribed to inadequate audiological counselling or a higher priority to other advice , e.g. on cardiovascular risk or lifestyle Objective Occupationally acquired noise-induced hearing loss ( NIHL ) is the most prevalent occupational disease in Austria and among the most common in many other countries . Because of the wide variation in hearing loss after equivalent exposures it has long been assumed that some individuals are more vulnerable to occupational NIHL than others . Earlier attempts to define predictors of NIHL before starting occupational noise exposure have largely failed . We present results of a prospect i ve study evaluating the potential of temporary threshold shift ( TTS ) after a test exposure to predict NIHL . Methods Between 1982 and 1989 , overall 311 apprentices were included into a prospect i ve study during their initial health screening visit . At this occasion , a st and ardised noise exposure was applied ( 20 min , 200–500 Hz , 100 dBA ) and the TTS at 4 kHz was determined during at least 10 min after exposure . Hearing loss was monitored at follow-up visits every 3–5 years . Follow-up was 13 years on average . Results Permanent threshold shift was predicted by duration of noise exposure , frequency of wearing noise protectors and especially by the initial TTS at 4 kHz . Using 14 dB TTS as a cut-off had 82 % sensitivity and 53 % specificity to predict 20 dB or higher levels of NIHL . Conclusions The TTS model can be successfully applied as a method to detect individuals at greater risk of occupational NIHL . It is recommended to routinely include such a procedure into initial workers ’ examinations for suitability to work under occupational noise conditions and for counselling on the use of hearing protectors OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity 
    Output:
    
There is very low- quality evidence that implementation of stricter legislation can reduce noise levels in workplaces .
There is moderate- quality evidence that training of proper insertion of earplugs significantly reduces noise exposure at short-term follow-up but long-term follow-up is still needed .
There is very low- quality evidence that the better use of hearing protection devices as part of HLPPs reduces the risk of hearing loss , whereas for other programme components of HLPPs we did not find such an effect .