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OBJECTIVE: To explore the effect of wearing earphone to listen to music on the high-frequency noise-induced hearing loss(NIHL) in noise-exposure workers. METHODS: A total of 651 male noise-exposure workers in an automobile manufacturer were selected as study subjects by using judgment sampling method. The level of noise exposure in the individuals and the pure tone hearing threshold were tested. According to the frequency of wearing earphone to listen to music after work, the subjects were divided into low-, medium-and high-frequency earphone-using groups, with 60, 436 and 155 workers in each group, respectively. The effects of wearing earphone to listen to music combined with occupational noise exposure on high-frequency NIHL were analyzed. RESULTS: The high-frequency NIHL detection rate of the study subjects was 31.3%(204/651). The detection rate of high-frequency NIHL in these three groups from low to high was low-, medium-and high-frequency earphone-using groups(P<0.01). The detection rate of high-frequency NIHL in the high-frequency earphone-using group was higher than that of the low-and medium-frequency earphone-using groups(43.2% vs 25.0%, 43.2% vs 28.0%, P<0.01). Multivariate logistic regression analysis showed that wearing earphones to listen to music was a risk factor for high-frequency NIHL in noise-exposure workers(P<0.01) after eliminating the influence of confounding factors such as age, length and level of noise-exposure, and wearing anti-noise ear plugs. The higher frequency of wearing earphone to listen to music, the higher risk of high-frequency NIHL. CONCLUSION: Wearing earphone to listen to music after work and occupational noise exposure had a synergistic effect on high-frequency NIHL in noise-exposure workers.
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OBJECTIVE: To observe the status of protein kinase B(Akt) signaling pathway in Akt phosphorylation induced by free silica(SiO_2) in mouse monocyte macrophage cell RAW264.7, and the role of Akt signaling pathway in early inflammatory response of silicosis. METHODS: i) RAW264.7 cells were routinely cultured and divided into SiO_2 stimulation groups at 5 different time points, and were stimulated for 15, 30, 60, 120 and 240 minutes with SiO_2 suspension with a final concentration of 100 mg/L, and a control group without SiO_2 treatment. At the end of treatment, the cells were collected and the expression of phospho-(Ser/Thr) Akt(p-Akt) was detected by Western blotting to select the optimal time of treatment. ii) RAW264.7 cells were divided into control group(no treatment), SiO_2 exposure group(previous concentration of 100 mg/L SiO_2 suspension) and intervention group(pre-treated with Akt activation inhibitor deguelin for one hour and then treated with 100 mg/L SiO_2 suspension), samples were collected after incubation for 60 minutes. The p-Akt expression and distribution in cells were detected by cellular immunofluorescence assay, the relative expression of p-Akt in cells was detected by Western blotting, and the levels of tumor necrosis factor-α(TNF-α) and transforming growth factor-β1(TGF-β1) in the supernatant of cells were detected by enzyme-linked immunosorbent assay. RESULTS: i) The optimal treatment time of RAW264.7 cells for SiO_2 exposure model was 60 minutes in vitro. ii) The results of cellular immunofluorescence assay showed that Akt phosphorylation was activated in RAW264.7 cells after stimulant with SiO_2, and the fluorescence of p-Akt was enhanced in the SiO_2 exposure group than the control group, and in the intervention group it was relatively weaker than the SiO_2 exposure group. The relative expression of p-Akt as well as the levels of TNF-α and TGF-β1 in the SiO_2 exposure group and the intervention group were higher than that in the control group(P<0.05), and the above three idexes in the intervention group were lower than the SiO_2 exposure group(P<0.05). CONCLUSION: Akt signaling pathway is involved in the process of SiO_2-induced macrophages phosphorylation, and participates in the early inflammatory response of silicosis.
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Objective@#To study the hearing status and analyze the related influencing factors in noise-exposed workers in an automobile manufacture enterprise, and put forward suggestions for prevention of noise-induced hearing loss.@*Methods@#Noise exposure level testing, audiometry testing and questionnaires were performed for noise exposed workers in the automobile manufacture enterprise. To analyze the relationship between different factors and noise-induced hearing loss by cumulative noise exposure(CNE) calculated 8-hour continuous A-weighted equivalent noise level and seniority.@*Results@#The detection rate of hearing loss in noise-exposed workers was 22.8%. The noise exposure intensity of stamping workshop is higher than other workshop, and the hearing loss detection rate of stamping workshop workers is higher than other workshop workers. The detection rate of hearing loss has significant difference in LAeq·8 h, seniority, CNE, age, high temperature and wearing earplugs (P<0.05). The results of logistic regression analysis showed that CNE, age and high-temperature were risk factors for noise-induced hearing loss (P<0.05 and OR>1) and there was an increasing tendency of hearing loss with increase in length of service and CNE, while using of earplugs was a protective factor (P<0.05 and OR<1). With the increase of CNE, the incidence of hearing loss is the rising trend.@*Conclusion@#It is suggested to strengthen the noise control and individual protection and improve the high-temperature working environment, which plays an important role in reducing the occurrence of noise-induced hearing loss.
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OBJECTIVE: To analyze the effect of occupational noise exposure on reproductive function in Chinese female workers.METHODS: The published literatures that showed the relationship between occupational noise exposure and female workers' reproductive function from Chinese National Knowledge Infrastructure,Wanfang Data,Chinese Biology Medicine Database and China Science and Technology Periodical Database from 1985 to 2016 were collected,screened and analyzed using bibliometric method.The Rev Man 5.2 software was used to calculate the pooled odds ratio(OR) and the 95%confidence interval(CI).RESULTS: A total of 25 original research papers were included.The occupational exposure to noise was significantly associated with abnormality of female menstrual cycle(OR = 2.26,95% CI: 1.70-3.01),dysmenorrheal(OR = 2.21,95% CI: 1.78-2.75),abnormal menstrual period(OR = 2.11,95% CI: 1.40-3.18),abnormal menstrual blood volume(OR = 1.73,95% CI: 1.34-2.23),pregnancy-induced hypertension(OR = 1.82,95% CI: 1.49-2.22),anemia in pregnancy(OR = 1.71,95% CI: 1.25-2.34),threatened abortion(OR = 1.98,95% CI: 1.23-3.20),spontaneous abortion(OR = 1.76,95% CI: 1.49-2.08),stillbirths(OR = 1.61,95% CI: 1.22-2.13),premature birth(OR = 1.57,95% CI: 1.36-1.81),neonatal low birth weight(OR = 1.66,95% CI: 1.39-1.98),and congenital malformations(OR = 1.58,95% CI: 1.10-2.27) compared with the controls(P<0.01).There was a doseresponse relationship between the above-mentioned indicators and the intensity of noise exposure.Occupational noise exposure was not associated with over-term birth(OR = 1.32,95% CI: 0.81-2.15,P>0.05) compared with the controls.CONCLUSION: Occupational noise exposure can affect the reproductive function and pregnancy outcomes of female workers.It is suggested that pregnant women should not be engaged in noise operations.
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OBJECTIVE: To examine the correlation between single nucleotide polymorphism( SNP) in 3' untranslated regions and hearing-related genes and their correlation with susceptibility in noise-induced hearing loss( NIHL) in Chinese Han population. METHODS: A total of 2 507 workers exposed to 72-120 d B( A) of normalized continuous A-weighted sound pressure level equivalent to a 40 h-working-week intensity of continuous noise in three large compressor manufacturing enterprises in Guangzhou were chosen as study subjects by judgment sampling method. A model was set up to define sensitive group( 238 sensitive workers) and resistant group( 238 resistant workers) by testing the workplace noise intensity and worker hearing pure tone threshold test. The genomic DNA from peripheral blood was collected from workers of these two groups. The genetic characteristic analysis was carried out by using the Taq Man probe with chemical fluorescence allelic identification test. RESULTS: The monaural threshold of weighted value( MTWV) of the left ear in sensitive group was higher than that of the right ear( P < 0. 01); the MTWV of left ear and right ear in sensitive group were respectively higher than that of the same ear in resistant group( P < 0. 01). A total of four candidate genes were screened: vesicle associated membrane protein 1( VAMP1),fibroblast growth factor 1( FGF1),potassium inwardly-rectifying channel,subfamily J,member 10( KCNJ10) and myosin IC( MYO1C). The results of SNP loci detection showed that more workers in sensitive group carried FGF1 rs17217562 AC and CC genotype than that of resistant group( P < 0. 05). More workers in sensitive group carried C allele of FGF1 rs17217562 than the resistant group( P < 0. 05). The logistic regression analysis showed that after correcting the confounding factors including age,noise exposure level,length of noise exposure,gender,smoking,drinking,whether or not using headset,organic solvents exposure,heavy metal exposure,high temperature exposure and hand-arm vibration exposure,the people carrying allele of FGF1 rs17217562 had an increased risk of NIHL susceptibility( P < 0. 05). The VAMP1,KCNJ10 and MYO1C gene had no susceptibility correlation with SNP and NIHL.CONCLUSION: Among Chinese Han population,SNP loci located on the FGF1 rs17217562 may be correlated with the susceptibility of NIHL.
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OBJECTIVE: To explore the relationship between noise-induced hearing loss, hypertension and abnormal electrocardiogram(ECG) in noise-exposed workers. METHODS: A judgment sampling method was adopted to select 555 male workers with hearing loss as study group and 555 male workers with normal hearing as control group in the similar environment in an automobile manufacturing enterprise in Guangzhou. Pure tone audiometry,blood pressure measurement and ECG examination were performed in both groups to analyze the relationship between hearing loss and hypertension and abnormal ECG. RESULTS: The prevalence rate of hypertension and abnormal ECG was higher in the hearing loss group than the control group(P < 0. 05). The multiple logistic regression analysis showed that after adjusting confounding factors such as age,seniority,body mass index,drinking et al,the risk of hypertension in hearing loss group was higher than the control group(P < 0. 05) and the odds ratio(OR) was 2. 255 [95% confidence interval(CI) : 1. 093-4. 655 ],while adjusting the confounding factor of drinking,the risk of ECG abnormalities in hearing loss group was higher than the control group(P < 0. 05) and the OR was 1. 408(95% CI: 1. 027-1. 930). CONCLUSION: Workers exposed to noise with hearing loss increase the risk of hypertension and abnormal ECG.