Analysis of the effect of hand-transmitted vibration on hearing loss in male noise-exposed workers / 中国职业医学

Objective To investigate the combined effect of noise and hand-transmitted vibration on hearing loss in male noise-exposed workers. Methods A total of 952 male noise-exposed workers from an automobile manufacturing enterprise were selected as the research subjects using judgment sampling method. Occupational epidemiological surveys, assessments of occupational hazards in workplace, and pure-tone audiometry tests were conducted on the research subjects, and they were divided into low-level noise group, low-level combined group, high-level noise group, and high-level combined group according to whether the noise exposure level exceeded the national standard and whether they were jointly exposed to hand-transmitted vibration. The joint effects of noise and hand-transmitted vibration on hearing loss were analyzed. Results The detection rate of hearing loss in 952 noise-exposed workers was 21.7%. The detection rate of hearing loss of four groups, from high to low, was as follows： high-level combined group, high-level noise group, low-level combined group, and low-level noise group (44.9% vs 32.7% vs 12.9% vs 5.7%, P<0.01). The results of multivariate logistic regression analysis showed that the risk of hearing loss in the low-level noise group, the low-level combined group, the high-level noise group and the high-level combined group increased sequentially after adjusting for the confounding factors such as age, education level, smoking, drinking, listening to music with headphones, frequency of wearing noise-blocking earplugs and body mass index. The risk of hearing loss in the high-level noise group was 8.62 times more than that of the low-level noise group (P<0.01). The risk of hearing loss in the low-level noise combined group was 2.50 times more than that of the low-level noise group (P<0.01). The risks of hearing loss in the high-level combined group were 5.76 and 1.67 times more than that of the low-level combined group and the high-level noise group. Conclusion Combined exposure to noise and hand-transmitted vibration can increase the risk of hearing loss in male noise-exposed workers, and the higher the noise intensity, the greater the synergistic effect. Hand-transmitted vibration is a synergistic risk factor for occupational noise-induced hearing loss.

Analysis of influencing factors of multi-site musculoskeletal disorders among workers in the chemical pharmaceutical industry / 中国职业医学

{L-End}Objective To analyze the prevalence of multi-site work-related musculoskeletal disorders (WMSDs) and their influencing factors among workers in the chemical pharmaceutical industry. {L-End}Methods A total of 563 workers from three chemical pharmaceutical factories in Guangzhou City were selected as the research subjects using the judgment sampling method. The prevalence of multi-site WMSDs in the past 12 months was investigated using the electronic questionnaire of Chinese Version of Musculoskeletal Disorders Questionnaire. {L-End}Results The prevalence of multi-site WMSDs in the research subjects was 30.0% (169/563). The results of multivariable logistic regression analysis showed that workers who smoked regularly/frequently and those who had their hands above shoulder level for long periods of time had a lower risk of multi-site WMSDs than those who never/occasionally smoked (all P≤0.05). Workers with a high school, secondary specialty, college degree, or above had a lower risk of multi-site WMSDs than those with a middle school education or below (all P<0.05). The longer the daily working hours, the higher the risk of multiple WMSDs (all P<0.05). Workers with regular/frequently work shifts had a lower risk of multi-site WMSDs than those with none/occasional work shifts (P<0.05). {L-End}Conclusion The prevalence of multi-site WMSDs among workers in the chemical pharmaceutical industry is relatively high. The influencing factors are individual factors, unreasonable work organization and poor ergonomics factors.

The effect of pulmonary injury in rats induced by paraquat / 中华劳动卫生职业病杂志

Objective@#To study the effect of sodium aescinate on the development process of lung injury induced by paraquat.@*Methods@#Forty-five health adult male SD rats were randomly divided into control group, PQ group, sodium aescinate group, and 15 rats in each group. The PQ group and sodium aescinate group were given a one-time intraperitoneal injection of 18mg/kg body weight of rats PQ, the control group was given the same amout normal saline. Rats in sodium aescinate group were injected 2 mg/kg body weight sodium aescinate into abdominal cavity for 7 days continually, but the same volume of saline was injected into the other groups. Finally, at 7, 14 and 28 days after PQ poisoning, five rats were kills for measuring lung tissue pathological changes and the value of TGF-β1, TNF-α, hydroxyproline in each group.@*Results@#The expression of TNF-α in serum of 7th day [ (17.03±0.82) ng/ml] and 14th day [ (15.74±0.91) ng/ml] of sodium aescinate group were lower than the corresponding period of PQ groups’, and the difference had statistical significance (P<0.05) . The expression of TGF-β1 in serum of 7th day[ (225.93±8.33) ng/ml], 14th day [ (216.62±9.48) ng/ml] and 28th[ (181.41±6.10) ng/ml] of sodium aescinate group were lower than the corresponding period of PQ groups’, and the difference had statistical significance (P<0.05) . Lung tissue pathological changes showed, compared with control group, inflammatory injury at 7th day and fibrosis degree at 28th of rats’ lung reduced on sodium aescinate group. The expression of hydroxyproline in rats’ lung of 7th day[ (1.246±0.018) μg/mg], 14th day [ (1.269±0.034) μg/mg] and 28th[ (1.283±0.028) μg/mg] of sodium aescinate group were lower than the corresponding period of PQ groups’, and the difference had statistical significance (P<0.05) .@*Conclusion@#sodium aescinate could reduce the pulmonary inflammatory injury and hydroxyproline value of PQ poisoning rats, so sodium aescinate could ameliorate lung injury induced by PQ.

Changes of integrin-linked kinase expression on rats’ pulmonary fibrosis induced by paraquat / 中华劳动卫生职业病杂志

Objective@#To observe the expression of integrin-linked kinase on pulmonary fibrosis of paraquat (PQ) poisoning rats, and to discuss the relationship between ILK with pulmonary fibrosis induced by paraquat.@*Methods@#Forty male Sprague-Dawley (SD) rats were randomly divided into control group and paraquat group, 20 in each group; the PQ group rats were intraperitoneally injected PQ liquid (18 mg/kg) , and the control group rats were injected the same volume of saline; 5 rats of these two groups were respectively sacrificed after 7, 14, 28, 56 days of PQ injection; according to the results of lung biopsy HE staining and Masson staining to observe the lung pathologic changes, measure the value of lung hydroxyproline and the expression of ILK.@*Results@#HE and Masson staining of lung pathological biopsy showed, the 7th day after PQ exposure lung tissue mostly had congestion, edema, inflammatory cells infiltration; the 14th inflammation reduced, fibrosis change appeared gradually; the 28th and 56th showed the lung tissue structure disorder and occurred apparent hydroproline with blue dye in pulmonary interstitium. Compared with control group in the same experiment period, the value of lung hydroxyproline in each experiment period of PQ group increased (P<0.05) , and the value of lung hydroxyproline of PQ group rose with the increasing of the time of PQ poisoning. The expression of ILK mRNA and protein in each experiment period of PQ group was higher than the control group in the same experiment period (P<0.05) ; ILK mRNA and protein of PQ group began to increase on 7 day phase, reached the highest on 28 day phase, and decreased on 56 day phase.@*Conclusion@#The expression of ILK mRNA and protein increased with the lung fibrosis progression of PQ poisoning rats, so ILK could be the key molecule target which induced pulmonary fibrosis of PQ poisoning.

Correlation between hearing-related gene polymorphism and susceptibility of noise-induced hearing loss / 中国职业医学

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.

Development of knowledge, attitude and practice questionnaire on prevention and control of occupational diseases / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To develop the knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups, and to provide a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect.</p><p><b>METHODS</b>The initial questionnaire which was evaluated by the experts was used to carry out a pre-survey in Guangzhou, China. The survey results were statistically analyzed by t test, identification index method, correlation analysis, and Cronbach's a coefficient method. And then the questionnaire was further modified, and the content of the questionnaire was determined finally.</p><p><b>RESULTS</b>After modification, there were 18 items on knowledge, 16 items on attitude, and 12 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for enterprise managers"; there were 19 items on knowledge, 10 items on attitude, and 11 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for workers".</p><p><b>CONCLUSION</b>The knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups is developed successfully, and it is a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect.</p>

Effect of noise on antioxidant capacity of brain tissue in guinea pigs / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect of noise on the antioxidant capacity in different regions of brain tissue in guinea pigs.</p><p><b>METHODS</b>Thirty male white red-eye guinea pigs were equally and randomly divided into five groups: 1-, 3-, 7-, and 14-day groups after noise exposure and control group. The guinea pigs of the experimental groups were exposed to steady white noise with a sound pressure level at 100 dB for 8 h per day and for 2 consecutive days. The auditory brainstem response (ABR) of guinea pigs, as well as the glutathione (GSH) level, methane dicarboxylic aldehyde (MDA) level, and superoxide dismutase (SOD) activity in the cerebrum, cerebellum, and hippocampus, was determined prior to and 1, 3, 7, and 14 days after noise exposure.</p><p><b>RESULTS</b>After noise exposure, the shifts in ABR threshold of the experimental groups were significantly higher than that of the control group (P<0.05). Compared with those in the control group, the SOD activity and GSH level both significantly decreased in the cerebrum tissue of each experimental group after noise exposure (P<0.05) and MDA content significantly increased in the 1-day group (P<0.05). As for cerebellum tissue, the SOD activity and GSH level in the 7-day group were significantly lower than those in the control group (P<0.05), but there was no difference in MDA level between each experimental group and the control group (P>0.05). In comparison with those in the control group, the GSH and MDA levels in the 1-day group after noise exposure were significantly higher, and the GSH and MDA levels in the 3-day group and the MDA level in the 7-day group after noise exposure were significantly lower (all P<0.05).</p><p><b>CONCLUSION</b>Noise exposure can lead to hearing loss and affect the antioxidant capacity of brain tissue, which indicates that the improvement in antioxidant levels may alleviate noise-induced damage.</p>