Exposure to lead increases the risk of meningioma and brain cancer: A meta-analysis

ObjectiveTo analyze the relationship between environmental lead exposure and various types of brain tumors.MethodsSearch databases PubMed, Web of Science, Embase and Chinese National Knowledge Infrastructure (CNKI) as of July 1, 2019. Stata 15.0 software was used for analysis.ResultsIn the case control, lead exposure was associated with gliomas and meningiomas 0.82 (95 % CI: 0.69, 0.95) and 1.06 (95 % CI: 0.65, 1.46). In the cohort study, lead exposure was associated with brain cancer and meningiomas 1.07 (95 % CI: 0.95, 1.19) and 1.06 (95 % CI: 0.94, 1.17). The risk of childhood brain tumors associated with parental lead exposure was 1.17 (95 % CI: 0.99, 1.34).ConclusionsLead may be a risk factor for meningiomas and brain cancers. However, the glioma results suggest that lead may be a protective factor, which needs to be further studied.     

Association between occupational exposure to mineral oil and rheumatoid arthritis: results from the Swedish EIRA case-control study

The aim of the present study was to investigate the association between exposure to mineral oil and the risk of developing rheumatoid arthritis (RA), and in addition to perform a separate analysis on the major subphenotypes for the disease; namely, rheumatoid factor (RF)-positive RA, RF-negative RA, anticitrulline-positive RA and anticitrulline-negative RA, respectively. A population-based case-control study of incident cases of RA was performed among the population aged 18-70 years in a defined area of Sweden during May 1996-December 2003. A case was defined as an individual from the study base who for the first time received a diagnosis of RA according to the American College of Rheumatology criteria of 1987. Controls were randomly selected from the study base with consideration taken for age, gender and residential area. Cases (n = 1,419) and controls (n = 1,674) answered an extensive questionnaire regarding lifestyle factors and occupational exposures, including different types of mineral oils. Sera from cases and controls were investigated for RF and anticitrulline antibodies. Among men, exposure to any mineral oil was associated with a 30% increased relative risk of developing RA (relative risk = 1.3, 95% confidence interval = 1.0-1.7). When cases were subdivided into RF-positive RA and RF-negative RA, an increased risk was only observed for RF-positive RA (relative risk = 1.4, 95% confidence interval 1.0-2.0). When RA cases were subdivided according to the presence of anticitrulline antibodies, an increased risk associated with exposure to any mineral oil was observed only for anticitrulline-positive RA (relative risk = 1.6, 95% confidence interval = 1.1-2.2). Analysis of the interaction between oil exposure and the presence of HLA-DR shared epitope genes regarding the incidence of RA indicated that the increased risk associated with exposure to mineral oil was not related to the presence of shared epitope genotypes. In conclusion, our study shows that exposure to mineral oil is associated with an increased risk to develop RF-positive RA and anticitrulline-positive RA, respectively. The findings are of particular interest since the same mineral oils can induce polyarthritis in rats.     

Occupational exposure to solar ultraviolet B radiation and risk of prostate cancer in Danish men

ObjectivesFormer epidemiological studies have indicated that solar ultraviolet B radiation (UV) may reduce the risk of prostate cancer, however, the evidence is inconclusive. To contribute with evidence, the present study aimed to evaluate the association between occupational UV exposure and prostate cancer in Danish men.MethodsA total of 12,268 men diagnosed with primary prostate cancer before age 70 were identified via the Danish Cancer Registry. The Danish Civil Registration System was used to randomly select five male controls matched on year of birth, alive and free of prostate cancer at the time of diagnosis of the index case. Full individual-level employment history was retrieved from the Danish Supplementary Pension Fund Register and linked to a job exposure matrix to assess occupational UV exposure. Conditional logistic regression was used to estimate odds ratios (ORs) with corresponding 95 % confidence intervals.ResultsWe observed an inverse association between ever exposure to occupational UV and prostate cancer (OR=0.93, 95 % CI: 0.89–0.97). Longer duration of exposure (≥20 years: OR=0.90, 95 % CI: 0.84–0.96) and highest cumulative exposure (OR=0.90, 95 % CI: 0.84–0.96) were both inversely associated with disease risk.ConclusionsThe present study indicates a modest protective effect from occupational UV exposure on the risk of prostate cancer. This finding needs further attention in future large-scale studies.     

Reducing aluminum: an occupation possibly associated with bladder cancer.

A case-control study, undertaken to identify reasons for the exceptionally high incidence of bladder cancer among men in the Chicoutimi census division of the province of Quebec, revealed an increased risk associated with employment in the electrolysis department of an aluminum reduction plant. The estimated relative risk was 2.83 (95% confidence interval; 1.06 to 7.54). An interaction was found between such employment and cigarette smoking, resulting in a combined relative risk of 5.70 (95% confidence interval: 2.00 to 12.30). These findings suggest that employment in an aluminum reduction plant accounts for part of the excess of bladder cancer in the region studied.     

Past exposure to sun,skin phenotype,and risk of multiple sclerosis: case-control study

Objective To examine whether past high sun exposure is associated with a reduced risk of multiple sclerosis.Design Population based case-control study.Setting Tasmania, latitudes 41-3°S.Participants 136 cases with multiple sclerosis and 272 controls randomly drawn from the community and matched on sex and year of birth.Main outcome measure Multiple sclerosis defined by both clinical and magnetic resonance imaging criteria.Results Higher sun exposure when aged 6-15 years (average 2-3 hours or more a day in summer during weekends and holidays) was associated with a decreased risk of multiple sclerosis (adjusted odds ratio 0.31, 95% confidence interval 0.16 to 0.59). Higher exposure in winter seemed more important than higher exposure in summer. Greater actinic damage was also independently associated with a decreased risk of multiple sclerosis (0.32, 0.11 to 0.88 for grades 4-6 disease). A dose-response relation was observed between multiple sclerosis and decreasing sun exposure when aged 6-15 years and with actinic damage.Conclusion Higher sun exposure during childhood and early adolescence is associated with a reduced risk of multiple sclerosis. Insufficient ultraviolet radiation may therefore influence the development of multiple sclerosis.     

Is fertility reduced among men exposed to radiofrequency fields in the Norwegian Navy?

The effects of radiofrequency fields on human health are not well understood, and public concern about negative health effects has been rising. The aim of this study was to examine the relationship between workers exposed to electromagnetic fields and their reproductive health. We obtained data using a questionnaire in a cross-sectional study of naval military men, response rate 63% (n = 1487). We asked the respondents about exposure, lifestyle, reproductive health, previous diseases, work and education. An expert group categorized the work categories related to electromagnetic field exposure. We categorized the work categories "tele/communication," "electronics" and "radar/sonar" as being exposed to electromagnetic fields. Logistic regression adjusted for age, ever smoked, military education, and physical exercise at work showed increased risk of infertility among tele/communication odds ratio (OR = 1.72, 95% confidence interval 1.04-2.85), and radar/sonar odds ratio (OR = 2.28, 95% confidence interval 1.27-4.09). The electronics group had no increased risk. This study shows a possible relationship between exposure to radiofrequency fields during work with radiofrequency equipment and radar and reduced fertility. However, the results must be interpreted with caution.     

Remote effects of occupational and non-occupational exposure to electromagnetic fields of power-line frequency. Epidemiological studies

A retrospective cohort study of mortality in the personnel of power-supply plants in the European regions of Russia was carried out. The exposure of the personnel to electromagnetic fields of power-line frequency (PF) was taken into account. Statistically non-significant raise of mortality from leukemia was found, compared to low mortality rates due to all other causes including cancer of any type. Standardized mortality ratio (SMR) was equal to 2.03 (95% CI = 0.23-7.31). In the retrospective case-control study the haemoblastosis development risk under occupational PF EMF exposure was evaluated. The data of 571 "cases" and 1208 "controls" interview showed that odd ratio (OR) was 1.64 (95% CI = 0.8-3.1). In another retrospective case-control study the risk of the haemoblastosis development in children due to parents PF EMF occupational exposure was evaluated. The data of 208 "cases" and 319 "controls" interview showed that the odd ratio (OR) was 1.69 (95% CI = 0.7-3.3). A retrospective cohort study of mortality in a settlement situated near a high-voltage (500 kV) substation, which took into account PF EMF levels in residential areas, revealed low mortality rates, except leukemia mortality (SMR 1.3; 95% CI = 0.2-7.0). The obtained data do not allow excluding a possibility of PF EMF leukogenic effect.     

Risk of cancer in Finnish children living close to power lines.

OBJECTIVE--To investigate the risk of cancer in children living close to overhead power lines with magnetic fields of > or = 0.01 microteslas (microT). DESIGN--Cohort study. SETTING--The whole of Finland. SUBJECTS--68,300 boys and 66,500 girls aged 0-19 years living during 1970-89 within 500 m of overhead power lines of 110-400 kV in magnetic fields calculated to be > or = 0.01 microT. Subjects were identified by record linkages of nationwide registers. MAIN OUTCOME MEASURES--Numbers of observed cases in follow up for cancer and standardised incidence ratios for all cancers and particularly for nervous system tumours, leukaemia, and lymphoma. RESULTS--In the whole cohort 140 cases of cancer were observed (145 expected; standardised incidence ratio 0.97, 95% confidence interval 0.81 to 1.1). No statistically significant increases in all cancers and in leukaemia and lymphoma were found in children at any exposure level. A statistically significant excess of nervous system tumours was found in boys (but not in girls) who were exposed to magnetic fields of > or = 0.20 microT or cumulative exposure of > or = 0.40 microT years. CONCLUSIONS--Residentia magnetic fields of transmission power lines do not constitute a major public health problem regarding childhood cancer. The small numbers do not allow further conclusions about the risk of cancer in stronger magnetic fields.     

Predictors of the risk of mortality in neurofibromatosis 2

To evaluate clinical and molecular predictors of the risk of mortality in people with neurofibromatosis 2 (NF2), we analyzed the mortality experience of 368 patients from 261 families in the United Kingdom NF2 registry, using the Cox proportional-hazards model and the jackknife method. Age at diagnosis, intracranial meningiomas, and type of treatment center were informative predictors of the risk of mortality. In Cox models, the relative risk of mortality increased 1.13-fold per year decrease in age at diagnosis (95% confidence interval [CI] 1.08-1.18) and was 2.51-fold greater in people with meningiomas compared with those without meningiomas (95% CI 1.38-4.57). The relative risk of mortality in patients treated at specialty centers was 0.34 compared with those treated at nonspecialty centers (95% CI 0.12-0.98). In a separate model, the relative risk of mortality in people with constitutional NF2 missense mutations was very low compared with those with other types of mutations (nonsense or frameshift mutations, splice-site mutations, and large deletions), but the CI could not be well quantified because there was only one death among people with missense mutations. We conclude that age at diagnosis, the strongest single predictor of the risk of mortality, is a useful index for patient counseling and clinical management (as are intracranial meningiomas). To ensure optimal care, we recommend that people with NF2 be referred to specialty treatment centers.     

Exposure to electrical contact currents and the risk of childhood leukemia

The objectives of this study were to examine the association between contact current exposure and the risk of childhood leukemia and to investigate the relationship between residential contact currents and magnetic fields. Indoor and outdoor contact voltage and magnetic-field measurements were collected for the diagnosis residence of 245 cases and 269 controls recruited in the Northern California Childhood Leukemia Study (2000-2007). Logistic regression techniques produced odds ratios (OR) adjusted for age, sex, Hispanic ethnicity, mother's race and household income. No statistically significant associations were seen between childhood leukemia and indoor contact voltage level [exposure ≥90th percentile (10.5 mV): OR = 0.83, 95% confidence interval (CI): 0.45, 1.54], outdoor contact voltage level [exposure ≥90th percentile (291.2 mV): OR = 0.89, 95% CI: 0.48, 1.63], or indoor magnetic-field levels (>0.20 μT: OR = 0.76, 95% CI: 0.30, 1.93). Contact voltage was weakly correlated with magnetic field; correlation coefficients were r = 0.10 (P = 0.02) for indoor contact voltage and r = 0.15 (P = 0.001) for outdoor contact voltage. In conclusion, in this California population, there was no evidence of an association between childhood leukemia and exposure to contact currents or magnetic fields and a weak correlation between measures of contact current and magnetic fields.     

Mortality among oral contraceptive users: 20 year follow up of women in a cohort study.

OBJECTIVE--To see whether the use of oral contraceptives influences mortality. DESIGN--Non-randomised cohort study of 17,032 women followed up on an annual basis for an average of nearly 16 years. SETTING--17 Family planning clinics in England and Scotland. SUBJECTS--Women recruited during 1968-74. At the time of recruitment each woman was aged 25-39, married, a white British subject, willing to participate, and either a current user of oral contraceptives or a current user of a diaphragm or intrauterine device (without previous exposure to the pill). MAIN OUTCOME MEASURES--Overall mortality and cause specific mortality. RESULTS--238 Deaths occurred during the follow up period. The main analyses concerned women entering the study while using either oral contraceptives or a diaphragm or intrauterine device. The overall relative risk of death in the oral contraceptive users was 0.9 (95% confidence interval 0.7 to 1.2). Though the numbers of deaths were small in most individual disease categories, the trends observed were generally consistent with findings in other reports. Thus the relative risk of death in the oral contraceptive users was 4.9 (95% confidence interval 0.7 to 230) for cancer of the cervix, 3.3 (95% confidence interval 0.9 to 17.9) for ischaemic heart disease, and 0.4 (95% confidence interval 0.1 to 1.2) for ovarian cancer. There was a linear trend in the death rates from cervical cancer and ovarian cancer (in opposite directions) with total duration of oral contraceptive use. Death rates from breast cancer (relative risk 0.9; 95% confidence interval 0.5 to 1.4) and suicide and probable suicide (relative risk 1.1; 95% confidence interval 0.3 to 3.6) were much the same in the two contraceptive groups. In 1981 the relative risk of death in oral contraceptive users from circulatory diseases as a group was reported to be 4.2 (95% confidence interval 2.3 to 7.7) in the Royal College of General Practitioners oral contraception study. The corresponding relative risk in this study was only 1.5 (95% confidence interval 0.7 to 3.0). CONCLUSIONS--These findings contain no significant evidence of any overall effect of oral contraceptive use on mortality. None the less, only small numbers of deaths occurred during the study period and a significant adverse (or beneficial) overall effect might emerge in the future. Interestingly, the mortality from circulatory disease associated with oral contraceptive use was substantially less than that found in the Royal College of General Practitioners study.     

Childhood exposure to ionizing radiation to the head and risk of schizophrenia

While the association between exposure to ionizing radiation and cancer is well established, its association with schizophrenia is unclear. The aim of our study was to assess risk of schizophrenia after childhood exposure to ionizing radiation to the head (mean dose: 1.5 Gy). The study population included an exposed group of 10,834 individuals irradiated during childhood for treatment of tinea capitis in the 1950s and two unexposed comparison groups of 5392 siblings and 10,834 subjects derived from the National Population Registry individually matched to the exposed group by age, sex (when possible), country of birth, and year of immigration to Israel. These groups were followed for a median 46 years for diagnosis of schizophrenia updated to December 2002. The Cox proportional hazards model stratified by matched sets was used to compare the risk of schizophrenia between the groups. Based on 1,217,531 person-years of follow-up, 451 cases were identified. No statistically significant association was found between radiation exposure and schizophrenia for the total group (hazard ratio per 1 Gy to the brain: 1.05, 95% confidence interval: 0.93-1.18) or within subgroups of sex, dose categories or latent period. When comparing a subgroup of subjects irradiated under 5 years of age with the matched unexposed group, the estimated hazard ratio reached 1.18 (95% confidence interval: 0.96-1.44; P = 0.1). The results of our analysis do not support an association between exposure to ionizing radiation and risk of schizophrenia. More research on possible effects of early exposure to ionizing radiation on schizophrenia specifically and brain tissue in general is needed.     

Dysregulation of Autonomic Control of Cardiac Function in Workers at am Broadcasting Stations (0.738–1.503 MHz)

Ninety-three adult males working at AM broadcasting stations (0.738–1.503 MHz) or radio line stations volunteered for cardiological examinations. The examinations included routine electrocardiogram (ECG) at rest, analysis of heart rate variability (HRV), Holter 24-h ECG, and 24-h ambulatory blood pressure (ABP). Results of cardiological examinations were correlated with individual exposure to EM fields (maximum exposure levels during working shift, daily exposure dose, and cumulative lifetime exposure). Of the 93 subjects qualified for the study, 71 (76.3%) experienced occupational RF exposure, while the remaining 22 (23.7%) had no history of regular EM exposure. ECG abnormalities or pathological changes were recorded quite frequently (50–70%) in both exposed and control populations. There was no correlation with exposure levels. We found measurable effects in the HRV and ABP parameters in the EM-exposed population, but none could be assigned clinical significance. The results suggest that exposure of workers to EM fields can cause slight disturbances in autonomic cardiac regulation and slight dysregulation of circadian rhythms in workers exposed to EM fields exceeding 100–150 V/m.     

Lenticular opacities in individuals exposed to ionizing radiation in infancy.

Development of lens opacities and the measures taken to avoid them have clinical relevance in the fields of oncology, radiotherapy and radiation protection. The aim of this study was to correlate the prevalence of lenticular opacities in individuals exposed to ionizing radiation in childhood with radiation dose and other possible risk factors. Between 1920 and 1959, about 16,500 children (age <18 months) with skin hemangiomas were referred to Radiumhemmet, Karolinska University Hospital, 89% of whom were treated with radiotherapy. A total of 484 exposed individuals and 89 nonexposed controls participated in an ophthalmological examination. Lens opacities were found in 357 (37%) of the 953 lenses examined in the exposed persons. In contrast, lens opacities were observed in only 35 (20%) of the 178 lenses examined in the nonexposed control individuals. It is concluded that the increased prevalence of cortical and posterior subcapsular opacities is related to previous radiotherapy. Age at examination was the strongest modifier of risk. Children exposed to a lenticular dose of 1 Gy had a 50% increased risk (odds ratio 1.50; 95% confidence interval 1.10-2.05) of developing a posterior subcapsular opacity and a 35% increased risk of a cortical opacity (odds ratio 1.35; 95% confidence interval 1. 07- 1.69).     

Long-term follow-up for brain tumor development after childhood exposure to ionizing radiation for tinea capitis

Ionizing radiation is an established risk factor for brain tumors, yet quantitative information on the long-term risk of different types of brain tumors is sparse. Our aims were to assess the risk of radiation-induced malignant brain tumors and benign meningiomas after childhood exposure and to investigate the role of potential modifiers of that risk. The study population included 10,834 individuals who were treated for tinea capitis with X rays in the 1950s and two matched nonirradiated groups, comprising population and sibling comparison groups. The mean estimated radiation dose to the brain was 1.5 Gy. Survival analysis using Poisson regression was performed to estimate the excess relative and absolute risks (ERR, EAR) for brain tumors. After a median follow-up of 40 years, an ERR/Gy of 4.63 and 1.98 (95% CI = 2.43-9.12 and 0.73-4.69) and an EAR/Gy per 10(4) PY of 0.48 and 0.31 (95% CI = 0.28-0.73 and 0.12-0.53) were observed for benign meningiomas and malignant brain tumors, respectively. The risk of both types of tumors was positively associated with dose. The estimated ERR/Gy for malignant brain tumors decreased with increasing age at irradiation from 3.56 to 0.47 (P = 0.037), while no trend with age was seen for benign meningiomas. The ERR for both types of tumor remains elevated at 30-plus years after exposure.     

Hypothesis: The risk of childhood leukemia is related to combinations of power-frequency and static magnetic fields

We present a hypothesis that the risk of childhood leukemia is related to exposure to specific combinations of static and extremely-low-frequency (ELF) magnetic fields. Laboratory data from calcium efflux and diatom mobility experiments were used with the gyromagnetic equation to predict combinations of 60 Hz and static magnetic fields hypothesized to enhance leukemia risk. The laboratory data predicted 19 bands of the static field magnitude with a bandwidth of 9.1 μT that, together with 60 Hz magnetic fields, are expected to have biological activity. We then assessed the association between this exposure metric and childhood leukemia using data from a case-control study in Los Angeles County. ELF and static magnetic fields were measured in the bedrooms of 124 cases determined from a tumor registry and 99 controls drawn from friends and random digit dialing. Among these subjects, 26 cases and 20 controls were exposed to static magnetic fields lying in the predicted bands of biological activity centered at 38.0 μT and 50.6 μT. Although no association was found for childhood leukemia in relation to measured ELF or static magnetic fields alone, an increasing trend of leukemia risk with measured ELF fields was found for subjects within these static field bands (P for trend = 0.041). The odds ratio (OR) was 3.3 [95% confidence interval (CI) = 0.4–30.5] for subjects exposed to static fields within the derived bands and to ELF magnetic field above 0.30 μT (compared to subjects exposed to static fields outside the bands and ELF magnetic fields below 0.07 μT). When the 60 Hz magnetic fields were assessed according to the Wertheimer-Leeper code for wiring configurations, leukemia risks were again greater with the hypothesized exposure conditions (OR = 9.2 for very high current configurations within the static field bands: 95% CI = 1.3–64.6). Although the risk estimates are based on limited magnetic field measurements for a small number of subjects, these findings suggest that the risk of childhood leukemia may be related to the combined effects of the static and ELF magnetic fields. Further tests of the hypothesis are proposed. © 1995 Wiley-Liss, Inc.     

Bendectin and human congenital malformations

The relationship between Bendectin exposure during the first trimester of pregnancy and the occurrence of congenital malformations was prospectively studied in 31,564 newborns registered in the Northern California Kaiser Permanente Birth Defects Study. The odds ratio for any major malformation and Bendectin use was 1.0 (95% confidence interval 0.8-1.4). There were 58 categories of congenital malformations; three of them were statistically associated with Bendectin exposure (microcephaly--odds ratio = 5.3, 95% confidence interval = 1.8-15.6; congenital cataract--odds ratio = 5.3, 95% confidence interval = 1.2-24.3; lung malformations (ICD-8 codes 484.4-484.8)--odds ratio = 4.6, 95% confidence interval = 1.9-10.9). This is exactly the number of associations that would be expected by chance. An independent study (the Collaborative Perinatal Project) was used to determine whether vomiting during pregnancy in the absence of Bendectin use was associated with these three malformations. Two of the three (microcephaly and cataract) had strong positive associations with vomiting in the absence of Bendectin use. We conclude that there is no increase in the overall rate of major malformations after exposure to Bendectin and that the three associations found between Bendectin and individual malformations are unlikely to be causal.     

Combined effect of prenatal solvent exposure and GSTT1 or GSTM1 polymorphisms in the risk of birth defects

Exposure to solvents during pregnancy has long been suspected to increase the risk of congenital malformations. Glutathione S-transferases (GSTs) are enzymes essential for the detoxification of various chemicals. Our objective here was to assess whether GST polymorphisms might modify the association between maternal solvent exposure and the risk of birth defects. A prospective cohort included 3421 pregnant women in Brittany, France (2002-2006). Occupational exposure to solvents was assessed from a job-exposure matrix. Congenital malformations were diagnosed among livebirths, stillbirths, and medical pregnancy terminations. Using a nested case-control design, 32 babies with major birth defects were compared to 348 normal births for babies' cord blood genotypes (at GSTT1 and GSTM1) and maternal occupational solvent exposure. Logistic models were used to adjust for potential confounders. The risk of major defects increased significantly in women with solvent exposure (20% of controls and 34% of cases). Frequencies of the null genotype of both the GSTT1 and GSTM1 genes were similar among controls and cases. There was a significantly increased risk of birth defects in GSTM1 not-null cord-blood genotype in pregnancies exposed to solvents (odds ratio [OR], 1.0 for not-null, not-exposed; OR, 4.0 for not-null, exposed; 95% confidence interval [CI], 1.4-11.2; OR, 1.6 for null, not-exposed; 95% CI, 0.6-3.9; OR, 1.0 for null, exposed; 95% CI, 0.2-4.7; p = 0.05). This nested case-control study suggests that the child's GSTM1 genotype modifies the risk of major birth defects among offspring of solvent-exposed women. Replication and additional investigations are necessary to confirm and elucidate these findings.     

Noise and the classical musician.

OBJECTIVES--To test the hypothesis that noise exposure may cause hearing loss in classical musicians. DESIGN--Comparison of hearing levels between two risk groups identified during the study by measuring sound levels. SETTING--Symphony orchestra and occupational health department in the west Midlands. MAIN OUTCOME MEASURES--Hearing level as measured by clinical pure tone audiometry. RESULTS--Trumpet and piccolo players received a noise dose of 160% and 124%, respectively, over mean levels during part of the study. Comparison of the hearing levels of 18 woodwind and brass musicians with 18 string musicians matched for age and sex did not show a significant difference in hearing, the mean difference in the hearing levels at the high (2, 4, and 8 KHz) audiometric frequencies being 1.02 dB (95% confidence interval -2.39 to 4.43). CONCLUSIONS--This study showed that there is a potential for occupational hearing loss in classical orchestral musicians.     

Frequency-specific association of antibodies against heat shock proteins 60 and 70 with noise-induced hearing loss in Chinese workers

Noise exposure may result in production of auto-antibodies against heat shock proteins (Hsps), which might be of significance in the pathogenesis or prognosis (or both) of auto-immune ear diseases. However, it is not known whether these antibodies are associated with noise-induced hearing loss (NIHL) in workers exposed to noise in occupational settings. Using immunoblotting with human recombinant Hsps, audiological assessment, and multivariate logistic regression models, we investigated the presence of antibodies against Hsp60 and Hsp70 and hearing levels, and analyzed their associations with NIHL in 399 workers exposed to noise between 75 and 115 dB. Our findings showed that the prevalence of positive anti-Hsp70 was significantly higher in the workers with slight and moderate high-frequency hearing loss than in normal workers (P < 0.05). Furthermore, the prevalence of positive anti-Hsp60 in workers with moderate low-frequency NIHL was significantly higher than in the normal (P < 0.01). The levels of anti-Hsp70 and anti-Hsp60 seemed correlated, and the level of anti-Hsp70 better predicted the level of anti-Hsp60. An elevated plasma level of anti-Hsp70 was associated with a nonsignificantly increased risk of high-frequency NIHL (adjusted OR = 1.45; 95% CI = 0.89-2.36) and an elevated plasma level of anti-Hsp60 was associated with a nonsignificantly increased risk of the low-frequency NIHL (adjusted OR = 2.25; 95% CI = 0.85-5.96). These results suggest that the production of anti-Hsp60 and anti-Hsp70 may play a role in the pathogenesis of NIHL, and that anti-Hsps may be a risk factor. The precise mechanisms for the elevation of antibodies against Hsps caused by noise exposure and their possible role in the development of NIHL warrant further investigations.