Prevalence and patterns of hearing loss among chronic kidney disease patients undergoing haemodialysis

Background

The prevalence, degree, and patterns of hearing loss associated with chronic kidney disease (CKD) reported by various studies differ significantly. The effects of haemodialysis and duration of disease on hearing loss remain unclear.

Aims

The aim of this study was to determine the prevalence and degree of hearing loss in CKD patients on haemodialysis.

Methods

This study included 120 CKD patients on haemodialysis. Information regarding age, gender, duration of disease, subjective hearing loss, exposure to ototoxic drugs, comorbidities like diabetes, hypertension, and hypothyroidism, renal functions, electrolytes and number of haemodialysis sessions received were obtained. An equal number of age and sex matched controls were used to determine prevalence of hearing loss in CKD patients after subjecting both groups to pure tone audiometry. We compared CKD patients with and without hearing loss for association of hearing loss with disease duration, number of haemodialysis, and blood parameters.

Results

Hearing loss was present in 41.7 per cent of CKD patients, significantly higher than controls (p=0.001), and was mild in the majority of patients. Impairment was noted across high and low frequencies of audiometric testing. Median duration of disease was the same (18 months) among CKD patients with and without hearing loss (p=0.62). CKD patients with hearing loss received 72 haemodialysis compared to 122 sessions by those without hearing loss (p=0.04).

Conclusion

Mild sensorineural hearing loss is common in CKD. Hearing loss has no specific pattern as it prevails at high and low frequencies. Hearing loss may be inversely associated with the number of haemodialysis sessions but not with duration of disease.     

Risk factors and 30-day case fatality of first-ever stroke in Basrah,Iraq

Background:

The aim of this hospital-based study is to determine the types, the frequency of risk factors and the 30-day case fatality of first-ever stroke in Basrah, Iraq.

Materials and Methods:

This was a hospital-based prospective study between January 2008 and July 2008 in Basrah, Iraq. Two hundred twenty-five (225) patients, who were admitted for first-ever stroke to the four major hospitals in Basrah, were interviewed and followed up for 30 days. Risk factors studied were smoking, history of diabetes mellitus, hypertension, atrial fibrillation, ischaemic heart diseases and transient ischaemic attack.

Results:

The mean age of the studied subjects was 63.8 ± 12.3 years. Males constituted 56% of cases. Clinical types of stroke were ischaemic stroke (83.6%), intracerebral haemorrhage (16%) and subarachnoid haemorrhage (0.4%). The prevalence of risk factors was; hypertension (66.2%), family history of stroke (31.6%), ischaemic heart diseases (28.9%), smoking (28.4%), diabetes mellitus (28%), transient ischaemic attack (10.2%), atrial fibrillation (9.8%) and heart failure (5.8%). The 30-day case fatality rate was 22.7%.

Conclusions:

Ischaemic stroke was the highly prevalent type. Hypertension, family history of stroke, ischaemic heart diseases, smoking and diabetes mellitus were the major risk factors of first ever stroke in Basrah. The 30-day case fatality rate of stroke in Basrah was nearly similar to that in western countries, but higher than that reported in the neighbouring Arab countries. Early detection of modifiable risk factors that can prevent stroke or at least minimise its complications is highly recommended.     

Prevalence and Parental Awareness of Hearing Loss in Children with Down Syndrome

Background:

To establish the prevalence of hearing deficit in children with Down syndrome (DS) in Hong Kong as measured by brainstem auditory evoked potentials (BAEP). The secondary objective is to examine the agreement between BAEP and clinical questioning in detecting hearing deficit in DS.

Methods:

Consecutive DS patients attending the Down''s Clinic in a regional pediatric referral center were recruited into this cross-sectional study. BAEP data performed within 12 months were retrieved. The care-taker was interviewed with a structured questionnaire to detect any symptom of hearing impairment. BAEP findings and clinical questionings were compared in an agreement analysis using quadratic weighted kappa statistics.

Results:

Fifty DS patients (35 male, 15 female, mean age 11.70 years ± 5.74 standard deviation) were recruited. Eighteen patients (36.0%) were identified having hearing deficit by BAEP. Among patients with hearing impairment, 13 patients (72.2%) had a conductive deficit, and most have mild to moderate hearing loss. Five patients (27.8%) had sensorineural deficit and most have moderate to severe degree. Eight (44.4%) had bilateral hearing deficit. Care-takers of 13 patients (26.0%) reported symptoms of hearing impairment, with 9 (69.2%) having mild symptoms, 3 (23.1%) had moderate symptoms and 1 (7.7%) had severe symptoms. The weighted kappa was 0.045 (95.0% confidence interval − 0.138–0.229), indicating very poor strength of agreement between BAEP and clinical questioning. For patients with conductive hearing impairment, only 1 patients (7.7%) recalled history of otitis media.

Conclusions:

The estimated point prevalence of hearing impairment in Chinese DS children in Hong Kong is 36%. Our finding of poor strength of agreement between objective testing and symptom questioning reflects significant underestimation of hearing impairment by history taking alone. In view of the high prevalence and low parental awareness, continuous surveillance of hearing is mandatory for DS patients throughout childhood and adolescence.     

Identification of Two Disease-causing Genes TJP2 and GJB2 in a Chinese Family with Unconditional Autosomal Dominant Nonsyndromic Hereditary Hearing Impairment

Background:

There are more than 300 genetic loci that have been found to be related to hereditary hearing impairment (HHI), including 92 causative genes for nonsyndromic hearing loss, among which 34 genes are related to autosomal dominant nonsyndromic HHI (ADNSHHI). Traditional linkage analysis and candidate gene sequencing are not effective at detecting the ADNSHHI, especially for the unconditional families that may have more than one pathogenic cause. This study identified two disease-causing genes TJP2 and GJB2 in a Chinese family with unconditional ADNSHHI.

Methods:

To decipher the genetic code of a Chinese family (family 686) with ADNSHHI, different gene screening techniques have been performed, including linkage analysis, candidate genes screening, high-throughput sequencing and Sanger sequencing. These techniques were done on samples obtained from this family over a period of 10 years.

Results:

We identified a pathogenic missense mutation, c. 2081G>A (p.G694E), in TJP2, a gene that plays a crucial role in apoptosis and age-related hearing loss (ARHL). The mutation was co-segregated in this pedigree in all, but not in the two patients who presented with different phenotypes from the other affected family members. In one of the two patients, we confirmed that the compound heterozygosity for p. Y136* and p.G45E in the GJB2 gene may account for the phenotype shown in this patient.

Conclusions:

We identified the co-occurrence of two genetic causes in family 686. The possible disease-causing missense mutation of TJP2 in family 686 presents an opportunity for further investigation into ARHL. It is necessary to combine various genes screening methods, especially for some unconventional cases.     

Diabetes management in Australian rural aged care facilities: A cross--sectional audit

Background

There is gap in the literature regarding the current practice of diabetes management of the elderly in Australia and its compliance with available Australian diabetes practice guidelines.

Aims

The aims of this study were to describe the pharmacological management of elderly residents with diabetes living in aged care facilities and to identify areas for improvement in the current management as recommended by the current diabetes management guidelines in Australia.

Method

Residents with diabetes from three rural aged care facilities were identified by nursing staff. A cross-sectional medical record audit was carried out to obtain data of residents diagnosed with diabetes.Thirty-four medical records were audited from three aged care facilities.Data including demographics, medical histories and medications were collected and analysed.

Results

This study had two key findings; Firstly, it showed that about a third of residents with type 2 diabetes are managed with diet only. Secondly, of the residents who are managed with medications, less than half of those audited (41%) were managed according to the current diabetes guidelines in terms of pharmacological treatment which included anti- hypertensive, lipid lowering and anti- platelet therapies. Of those patients with a history of CVD, all were receiving an antihypertensive medication, 71% were not managed for their lipids and 20% were not on any prophylactic anti- platelet therapy.

Conclusion

Management of patients with diabetes living in rural aged care facilities is inconsistent with the current management guidelines. Educational interventions targeting health professionals and patients might be beneficial to increase compliance with the current diabetes guidelines.     

Oral steroid treatment for idiopathic sudden sensorineural hearing loss

Objectives:

To describe the efficacy of long-term oral steroids in idiopathic sudden sensorineural hearing loss (ISSHL), and to explore potential prognosis factors, the relationship of hearing recovery outcome, and the recovery time-course in ISSHL.

Methods:

In this retrospective study, we analyzed 215 cases diagnosed with idiopathic unilateral sudden deafness between January 2003 and December 2012 at a regional hospital in southern Taiwan. All of them received oral steroid therapy and were followed for at least 3 months.

Results:

Young age, the presence of no other disease (diabetes, hypertension, or cardiovascular disease), treatment within 7 days of the onset of ISSHL, mild hearing loss, and audiograms with ascending curves had a statistically significant better hearing recovery. The average pure-tone audiometry (PTA) was 67.8±23.9 dB initially, and was improved between one month (51.6±28.7 dB) and 2 months post treatment (49.7±28.6 dB). The average last-visit PTA was 49.9±29.2 dB.

Conclusion:

Approximately one third of patients had full recovery in hearing, one third had partial recovery, and approximately one third did not recover from hearing loss. In addition, the hearing level remained relatively stable following 2 months of treatment. More than 2 months of oral steroid therapy for ISSHL is not recommended because no additional benefits were evidenced.Idiopathic sudden sensorineural hearing loss (ISSHL) is defined as a sensorineural hypoacusis of at least 30 dB over 3 consecutive speech frequencies, occurring within 3 days. It is considered to be an otologic emergency, and the incidence has been estimated to range from 3.9 to 27.5 per 100,000 persons per year.1 Although the exact cause is still unknown, it has been hypothesized to be caused by viral infection of the labyrinth or cochlear nerve, vascular insult, intra labyrinthine membrane rupture, and autoimmunity.2 Owing to the variations in the etiopathogenesis of ISSHL, different therapeutic strategies have been developed. Steroids or in combination with vasodilators, plasma expanders, diuretics, anticoagulants, antiviral, vitamins, cytotoxic medications, hyperbaric oxygen, stellate ganglion block, and inhaled carbogen, have become the most widely accepted treatment options.2-7 However, the length of oral steroid therapy had not been well established. Most of the studies reported the length of steroid therapy ranging between 5-24 days.2-7 Although little is known about the time course of hearing loss for most patients, improvement in hearing can be anticipated only during the first 1-2 months. Therefore, this study investigated progression in recovery from sudden hearing loss, and the optimal treatment duration with oral steroids.     

Melanoma: A new strategy to reduce morbidity and mortality

Background

Public awareness campaigns could address risk factors for melanoma to reinforce their sun protection message. The objective of this study is to prioritise risk factors associated with malignant melanoma (MM) to improve public awareness.

Method

Design: A cross-sectional study with retrospective data analysis from 2004 to 2010. Setting: Western Australian Melanoma Advisory Service (WAMAS), a tertiary referral multidisciplinary organisation providing MM management advice. WAMAS data files were analysed with histologically confirmed cutaneous MM. Forty- seven patients had two or more melanomas, but the patient file was counted only once. Six MM data files with missing or incomplete information were excluded. Main outcome measures: The number of naevi, blood relatives with MM, and previous sunburns were the primary variables collected.

Results

The results showed that 70.9 per cent (268/378) had previous sunburn; 40.2 per cent (152/378) had multiple naevi; and 22.5 per cent (85/378) had a positive family history. In the 110 MM data files not associated with sunburn, multiple naevi and a positive family history represented 34.5 per cent (38/110) and 20.0 per cent (22/110), respectively.

Conclusion

The results confirm the findings of previous studies that multiple naevi and a positive family history are important risk factors associated with MM. We suggest that MM can be detected earlier and its mortality decreased by focusing on these high-risk groups who are not targeted by current public awareness campaigns.     

An audit of 3859 preadmission chest radiographs of apparently healthy students in a Nigerian Tertiary Institution

Background:

Chest radiographs are routinely requested as part of the medical screening process prior to admission to institutions. Literature on the yield of such an exercise is sparse especially in the Nigerian setting. This study was therefore carried out to assess the usefulness of routine chest radiography for students at the time of admission.

Materials and Methods:

This was a prospective study of 3859 chest X-rays taken at the department of radiology, University of Benin Teaching Hospital for one admission screening for the 2008/2009 academic year. The age and sex of the subjects were also recorded. The heart, lung fields and bony thorax were examined for any abnormality.

Results:

Out of the 3859 pre-admission chest radiographs studied, there were 1951 males or 50.56% and 1908 females or 49.44% subjects. The mean age for males was 21.15±3.

Conclusion:

This study has shown that pre-admission routine chest radiography in asymptomatic patients remains a relevant screening tool for medical fitness during admissions into institutions. However because of dangers of exposure to ionizing radiation, we advise that a detailed medical history and physical examination be done to restrict its use to only those subjects with signs and symptoms suggestive of disease.     

Prevalence of Noise Induced Hearing Loss in Indian Air Force Personnel

Background

Noise exposure is an inherent part of duty of the aircrew and maintenance staff in the Indian Air Force (IAF). An audiometric survey of IAF personnel was carried out to analyze the prevalence and severity of noise induced hearing loss (NIHL).

Methods

An audiometric study of 1000 IAF personnel of various trades, age and exposure groups were carried out at an operational base. Age related correction of 5 dB per decade was applied for personnel above SO years of age. Personal factors like smoking, blood group and use of ear defenders were analysed for their effect on the prevalence of NIHL.

Result

The study revealed an overall incidence of NIHL of 22.9 % in the personnel with a higher prevalence among the technical trades (26.18 %) as compared to non technical trades (12.5 %). There was a significant increase in prevalence of hearing loss with duration of exposure with 50.8% of personnel above 30 years of exposure having hearing loss. A higher incidence of hearing loss was observed in personnel of blood group O and smokers whereas use of ear defenders was protective.

Conclusion

The study reveals a significantly increased prevalence of NIHL among the technical trades of the IAF personnel. The deleterious effects of smoking and protective effect of regular use of ear defenders are emphasized.Key Words: Noise induced hearing loss, Smoking, Ear defenders     

Prevalence of depression in students of a medical college in New Delhi: A cross-sectional study

Background

Medical education is associated with various pressures and stresses which can lead to depression. This study was undertaken to discover the prevalence of depression in medical students and various factors contributing to depression.

Method

This is a cross-sectional, questionnaire-based study. Using stratified random sampling, 237 students were selected according to year of study. Patient Health Questionnaire (PHQ-9), based on PRIME-MD Today, was used to make a provisional diagnosis of depression.

Results

The overall prevalence of provisionally diagnosed depressive and major depressive disorder using PHQ-9 was 21.5% and 7.6%, respectively. Year of study and academic performance of students had a statistically significant association with depression. Other factors, including gender, self-reported past history of depression, family history of psychiatric disorders, type of social support, family structure, number of siblings and education of parents were not found to have any significant association with prevalence of depression in the study. It was also observed that students were reluctant to seek help for depressive symptoms.     

"Below the Line": The tobacco industry and youth smoking

Background

This paper provides a comprehensive account of how the tobacco industry, over time, has promoted its products to young people.

Method

A comprehensive search of tobacco industry documents relating to youth smoking was conducted using documents available on the World Wide Web through the Master Settlement Agreement.

Results

The documents provide evidence that the industry invested great time and resources in developing strategies to attract young people through Youth Smoking Prevention strategies (including education strategies) and marketing to youth. The results include information from published literature and direct excerpts from the tobacco industry documents.

Conclusion

The tobacco industry documents confirm that the tobacco industry has promoted and supported strategies that are ineffective in reducing smoking by youth, and opposed strategies that have proven to be effective. It is clear from the documents reviewed that the industry values the youth market and through a number of measures continues to promote its products to young people.     

Big tobacco "pull out all stops" for a landmark example: The Burswood Casino case

Background

With the aid of internal tobacco industry documents, this paper provides a chronology of events documenting the role of the Philip Morris tobacco company in the 1993 litigation case against the Burswood International Resort Casino (BIRC). The paper also examines the implications of this case for the regulation of second hand smoke exposure.

Method

A systematic keyword search and analysis of internal tobacco industry documents was conducted using documents available on the World Wide Web through the Master Settlement Agreement.

Results

The industry documents provide comprehensive evidence that the Philip Morris tobacco company provided assistance to the BIRC in its defence against action by the Western Australian government. The Philip Morris tobacco company, along with others, sought to publicise and promote the outcome as a ‘landmark example’ to lobby against the implementation of indoor smoking bans.

Conclusion

Philip Morris'' investment in the BIRC defence demonstrated the industry''s recognition of the potential significance of the case beyond Western Australia. Involvement in the BIRC case assisted the wider tobacco industry by helping to prolong smoking at casinos and other Australian hospitality venues. The findings contribute to our understanding of the history of tobacco industry strategies implemented in Western Australia and internationally to slow tobacco control progress, and the preparedness of the tobacco industry to exploit favourable developments originating anywhere in the world.     

A Mitochondrial DNA A8701G Mutation Associated with Maternally Inherited Hypertension and Dilated Cardiomyopathy in a Chinese Pedigree of a Consanguineous Marriage

Background:

Cardiovascular diseases, including dilated cardiomyopathy (DCM) and hypertension, are the leading cause of death worldwide. The role of mitochondrial DNA (mtDNA) in the pathogenesis of these diseases has not been completely clarified. In this study, we evaluate whether A8701G mutation is associated with maternally inherited hypertension and DCM in a Chinese pedigree of a consanguineous marriage.

Methods:

Fourteen subjects in a three-generation Han Chinese family with hypertension and DCM, in which consanguineous marriage was present in the parental generation, were interviewed. We divided all the family members into case (7 maternal members) and control group (7 nonmaternal members) for comparison. Clinical evaluations and sequence analysis of mtDNA were obtained from all participants. Frequency differences between maternal and nonmaternal members were tested to locate the disease-associated mutations.

Results:

The majority of the family members presented with a maternal inheritance of hypertension and DCM. Sequence analysis of mtDNA in this pedigree identified eight mtDNA mutations. Among the mutations identified, there was only one significant mutation: A8701G (P = 0.005), which is a homoplasmic mitochondrial missense mutation in all the matrilineal relatives. There was no clear evidence for any synergistic effects between A8701G and other mutations.

Conclusions:

A8701G mutation may act as an inherited risk factor for the matrilineal transmission of hypertension and DCM in conjunction with genetic disorders caused by consanguineous marriage.     

Prevalence and predictors of habitual snoring in a sample of Saudi middle-aged adults

Objectives:

To determine the prevalence of habitual snoring among a sample of middle-aged Saudi adults, and its potential predictors.

Methods:

A cross-sectional study was conducted from March 2013 until June 2013 in randomly selected Saudi Schools in Jeddah, Kingdom of Saudi Arabia. The enrolled subjects were 2682 school employees (aged 30-60 years, 52.1% females) who were randomly selected and interviewed. The questionnaire used for the interview included: the Wisconsin Sleep Questionnaire to assess for snoring, medical history, and socio-demographic data. Anthropometric measurements and blood pressure readings were recorded using standard methods.

Results:

Forty percent of the 2682 enrolled subjects were snorers: 23.5% were habitual snorers, 16.6% were moderate snorers, and 59.9%, were non-snorers. A multivariate analysis revealed that independent predictors of snoring were ageing, male gender, daytime sleepiness, hypertension, family history of both snoring and obstructive sleep apnea, water-pipe smoking, and consanguinity.

Conclusion:

This study shows that snoring is a common condition among the Saudi population. Previously reported risk factors were reemphasized but consanguinity was identified as a new independent predictive risk factor of snoring. Exploring snoring history should be part of the clinical evaluation.Snoring is defined as a harsh buzzing noise produced by vibration of the soft palate and pillars of the oropharyngeal inlet, primarily with inspiration during sleep. Habitual snoring (HS) is defined as the presence of loud snoring at least 3 nights per week, and is strongly associated with obstructive sleep apnea (OSA).1,2 Even in the absence of OSA, HS is associated with health and social consequences including sleep fragmentation, family discord, excessive daytime sleepiness, and more seriously, the development of systemic hypertension in individuals aged <50 years.3 However, many individuals regard HS as a benign and a common behavior; moreover, physicians often disregard snoring as a disorder in their clinical practice. Such denial may lead to delayed recognition and management of OSA.1 Loud snorers have a 40% greater chance of developing hypertension, 34% greater chance of developing heart attack, and 67% greater chance of developing stroke, compared to non-snorers after adjustments for age, gender, body mass index, diabetes, level of education, smoking, and alcohol consumption.4 More recently, heavy snoring has been independently associated with carotid atherosclerosis and treating it was suggested as an important goal in prevention of stroke.5 There have been many international epidemiological studies to establish the prevalence of habitual snoring. Habitual snoring was reported to affect 35.7% of American,2 37.2% of Polish,6 35% of Spanish,7 19.6% of Chinese,8,9 17.3% of Korean,10 and 25.6% of Indian populations.20 The main reported risk factors were aging, male gender, obesity, and smoking. However, very limited data is available on the prevalence and impact of HS in the Middle Eastern countries. A limited study on Saudi health care workers reported HS in only 5.4%.11 Another primary health care clinics based study found a snoring prevalence of 52.3% in Saudi males, and 40.8% in Saudi females.12,13 Therefore, we conducted the current study to assess the actual prevalence and risk factors predictive of HS in a cohort of subjects in Saudi Arabia. Our results will be used to assess the size of the problem and increase awareness of this health disorder among health care professions, so that sleep disordered breathing can be effectively diagnosed and treated.     

Solid Lipid Nanoparticles Loaded with Edaravone for Inner Ear Protection After Noise Exposure

Background:Antioxidants and the duration of treatment after noise exposure on hearing recovery are important.We investigated the protective effects of an antioxidant substance,edaravone,and its slow-re...     

Serum level of copper in patients with coronary artery disease

Background:

Atherosclerotic disease is the most important cause of mortality in the world. Oxidation is an important pathway in the pathogenesis of coronary artery disease (CAD) through oxidation of low-density lipoprotein (LDL) and free radical formation. Copper (Cu) is an essential micronutrient for enzymes that catalyse LDL oxidation reactions. Therefore, an evaluation of Cu in the atherosclerotic disease is important.

Materials and Methods:

In this study, 334 subjects without recent cardiac event and history of collagen vascular or infectious disease were investigated. All patients divided into four groups to evaluate severity of CAD according to Syntax scoring system. All groups were matched in cardiovascular risk factors.

Results:

The serum level of Cu was significantly higher in total atherosclerotic groups than normal group (P value = 0.001) and significantly increased with severity of atherosclerosis.

Conclusion:

The finding indicated that the serum level of Cu is higher in atherosclerotic patients and it increases with severity of atherosclerosis. Therefore, it may be possible that the basic relationship exist between serum Cu level and atherosclerosis and an association between Cu level and severity of atherosclerosis.     

A Survey of Deaf Mutes

Background

Detection of hearing loss at birth or early childhood is difficult. This bears on the rehabilitation of the child as the golden period of learning is lost. Reliable statistics relating the average age for detection of hearing loss and fitting of hearing aids in children are not available in our country. A survey of 52 deaf mutes was therefore conducted to ascertain the probable causes that lead to deafness.

Methods

The study subjects were 42 deaf mutes from the Government run school for deaf mutes and 10 from ASHA School run by the Army Wives Welfare Association. A questionnaire prepared in Hindi was filled by the parents and data analysed.

Results

The average age of detection of hearing loss was 2.8 years and the average age for receiving a hearing aid was 7.6 years. Thus due to the significant reduction of sensory input at the ‘golden period of learning’ only 50% of those fitted with a hearing aid found it useful. In 42.3% the cause of deafness could not be identified.

Conclusion

Greater emphasis is required on early diagnosis of childhood deafness and fitment of hearing aid.Key Words: Deaf mutes, Hearing aid     

Natural History of Small Renal Masses

Objective:

To review the natural history and growth kinetics of small renal masses (SRMs).

Data Sources:

The literature concerning natural history and growth kinetics of SRMs was collected from PubMed published from 1990 to 2014.

Study Selection:

We included all the relevant articles on the active surveillance (AS) or delayed treatment for SRMs in English, with no limitation of study design.

Results:

SRMs under AS have a slow growth potential in general. The mean linear growth rate is 0.33 cm/year, the mean volumetric growth rate is 9.48 cm³/year. The rate of metastasis during AS is below 2%. Some factors are associated with the growth rate of SRMs, including tumor grade, histological subtype, initial tumor size, age, radiographic characteristics, and molecular markers. No definite predictor of growth rate of SRMs is defined at present. SRMs with high tumor grade and the subtype of clear cell renal cell carcinoma may have aggressive growth potential.

Conclusions:

AS is a reasonable choice for elderly patients with SRMs, who are at high risk from surgery. Progression during observation is the biggest concern while performing AS. There is no definite predictor of progression for SRMs under AS. Percutaneous renal biopsy providing immunohistological and genic biomarkers may improve the understanding of natural history of SRMs.     

Comparison of Two Dose-response Relationship of Noise Exposure Evaluation Results with High Frequency Hearing Loss

Background:

Complex noise and its relation to hearing loss are difficult to measure and evaluate. In complex noise measurement, individual exposure results may not accurately represent lifetime noise exposure. Thus, the mean L_{Aeq,8 h} values of individuals in the same workgroup were also used to represent L_{Aeq,8 h} in our study. Our study aimed to explore whether the mean exposure levels of workers in the same workgroup represented real noise exposure better than individual exposure levels did.

Methods:

A cross-sectional study was conducted to establish a model for cumulative noise exposure (CNE) and hearing loss in 205 occupational noise-exposed workers who were recruited from two large automobile manufacturers in China. We used a personal noise dosimeter and a questionnaire to determine the workers’ occupational noise exposure levels and exposure times, respectively. A qualified audiologist used standardized audiometric procedures to assess hearing acuity after at least 16 h of noise avoidance.

Results:

We observed that 88.3% of workers were exposed to more than 85 dB(A) of occupational noise (mean: 89.3 ± 4.2 dB(A)). The personal CNE (CNEp) and workgroup CNE (CNEg) were 100.5 ± 4.7 dB(A) and 100.5 ± 2.9 dB(A), respectively. In the binary logistic regression analysis, we established a regression model with high-frequency hearing loss as the dependent variable and CNE as the independent variable. The Wald value was 5.014 with CNEp as the independent variable and 8.653 with CNEg as the independent variable. Furthermore, we found that the figure for CNEg was more similar to the stationary noise reference than CNEp was. The CNEg model was better than the CNEp model. In this circumstance, we can measure some subjects instead of the whole workgroup and save manpower.

Conclusions:

In a complex noise environment, the measurements of average noise exposure level of the workgroup can improve the accuracy and save manpower.