ABSTRACT
<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>In a complex noise environment, the measurements of average noise exposure level of the workgroup can improve the accuracy and save manpower.</p>
Subject(s)
Adult , Female , Humans , Male , Cross-Sectional Studies , Hearing Loss, High-Frequency , Diagnosis , Noise , Noise, Occupational , Occupational ExposureABSTRACT
<p><b>BACKGROUND</b>Task-based measurement (TBM) is a method to assess the eight-hour A-weighted equivalent noise exposure level (L(Aeq.8h)) besides dosimeter. TBM can be better used in factories by non-professional workers and staffs. However, it is still not clear if TBM is equal or similar with dosimeter for L(Aeq.8h) measurement in general. This study considered the measurement with dosimeter as real personal noise exposure level (PNEL) and assessed the accuracy of TBM by comparing the consistencies of TBM and dosimeter in L(Aeq.8h) measurement.</p><p><b>METHODS</b>The study was conducted in one automobile firm among 387 workers who are exposed to unstable noise. Dosimeters and TBM were used to compare the two strategies and assess the degree of agreement and causes of disagreement. Worker's PNEL was measured via TBM for noise; the real PNEL was also recorded. The TBM for noise was computed with task/position noise levels measured via sound level meter and workers' exposure information collected via working diary forms (WDF) filled by participants themselves. Full-shift noise exposure measurement via personal noise dosimeters were taken as the real PNEL. General linear model (GLM) was built to analyze the accuracy of TBM for noise and the source of difference between TBM for noise and real PNEL.</p><p><b>RESULTS</b>The L(Aeq.8h) with TBM were slightly higher than the real PNELs, except the electricians. Differences of the two values had statistical significance in stamping workers (P < 0.001), assembly workers (P = 0.015) and welding workers (P = 0.001). The correlation coefficient of L(Aeq.8h) with TBM and real PNELs was 0.841. Differences of the two results were mainly affected by real PNEL (F = 11.27, P = 0.001); and work groups (F = 3.11, P < 0.001) divided by jobs and workshops were also independent factors. PNEL of workers with fixed task/position ((86.53 ± 8.82) dB(A)) was higher than those without ((75.76 ± 9.92) dB(A)) (t = 8.84, P < 0.01). Whether workers had fixed task/position was another factor on the accuracy of TBM for noise (F = 4.36, P = 0.038).</p><p><b>CONCLUSION</b>TBM for noise has acceptable accuracy on workers' PNEL measurement. The accuracy is affected by job categories, workshops and variability of task/position. TBM for noise can yield a relatively conservative result of worker's PNEL in most cases, so it can be used to measure and assess workers' real PNEL.</p>
Subject(s)
Female , Humans , Male , Environmental Monitoring , Noise, OccupationalABSTRACT
<p><b>OBJECTIVE</b>To measure the concentration of osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (sRANKL) in peripheral blood among normal healthy people and investigate the relationship pf the concentration with age and sex.</p><p><b>METHODS</b>The peripheral blood samples of 220 normal healthy people (included 108 males and 112 females, aged from 35 to 70) were collected in the morning. The OPG and sRANKL concentration of blood serum were measured by ELISA.</p><p><b>RESULTS</b>The concentrations in female peripheral blood were: OPG 21.95 to 315.47 pg/ml, sRANKL 10.25 to 370.20 pmol/L; while in male were: OPG 14.78 to 192.55 pg/ml, sRANKL 9.22 to 300.32 pmol/L. There was positive correlation between the OPG concentration and age in the females older than 46 years. And for female older than 57, the sRANKL concentration of peripheral blood increases obviously.</p><p><b>CONCLUSION</b>Age and sex are the elements that affect the OPG and sRANKL concentration in peripheral blood. For female older than 46, the OPG concentration of peripheral blood increases with age, while the sRANKL concentration of peripheral blood increases for females older than 57.</p>