1,3-丁二烯作业工人XRCC4基因多态性与染色体损伤的关系

目的探讨DNA双链断裂修复酶XRCC4基因多态性与1,3-丁二烯(BD)作业工人染色体损伤易感性的关系。方法选取189名BD作业工人和83名行政人员作为研究对象,采用(CBMN)评价个体外周血淋巴细胞染色体损伤水平,用聚合酶链反应-限制性片段长度多态性方法分析XRCC4基因3个单体型标签单核苷酸多态性位点(A245G、T1394G和C1475T),Clark运算法确定个体XRCC4基因的单体型等位基因和单体型对,协方差分析校正相关影响因素,比较具有不同XRCC4基因型或单体型对的个体外周血淋巴细胞CBMN率的差异。结果在校正年龄、性别、吸烟、饮酒影响因素后,BD作业工人CBMN率为(7.17±5.41)‰、核质桥(NPB)率为(1.20±1.43)‰、核芽(NBUD)率为(2.87±2.44)‰,对照组的CBMN率为(3.10±2.56)‰、NPB率为(0.24±0.66)‰、NBUD率为(1.68±1.92)‰,差异有显著性(P0.01);暴露组中XRCC4A245G位点AA基因型个体NPB率显著高于AG基因型或GG基因型个体(P0.05);按年龄分层39岁组中XRCC4T1394G位点TT基因型个体CBMN率高于GG基因型个体(P0.01)。结论 XRCC4A245G和T1394G位点的多态性能影响职业性BD暴露导致的外周血淋巴细胞染色体损伤的易感性。     

三氯乙烯作业人群外周血淋巴细胞染色体损伤研究

目的探讨三氯乙烯(TCE)致作业人群外周血淋巴细胞染色体损伤的作用。方法以91名TCE暴露工人和59名对照作为研究对象,调查职业史、年龄、性别、吸烟和饮酒等信息。收集班后尿,测定尿中三氯乙酸(TCA)水平反映TCE暴露内剂量。抽取肘静脉血,胞质分裂阻滞微核法制备外周血淋巴细胞涂片,计数微核、核质桥和核芽发生率,评价染色体损伤水平。结果两组研究对象在年龄、性别、吸烟、饮酒状况等方面均无显著性差异。暴露组平均TCE作业工龄为1.8年。暴露组尿中TCA水平为57.5mg/L,远远高于对照组0.9mg/L。两组研究对象的微核率及核质桥率无显著差异,但暴露组核芽率[(1.6±1.0)‰]显著高于对照组[(1.2±0.8)‰,P=0.05]。核芽率的升高在尿TCA≥50.0 mg/L组和TCE作业工龄≥1.8年组中表现更为明显。同时,尿TCA≥50.0 mg/L的工人,其微核率[(1.8±0.9)‰]也显著高于对照组[(1.4±0.7)‰,P=0.05]。未发现年龄、性别、吸烟、饮酒对微核率、核质桥率、核芽率的显著影响。结论 TCE暴露可致作业工人染色体损伤增加,核芽可以较为敏感的检出由TCE职业暴露所引发的基因组不稳定性。     

Evaluation of genotoxic effects of lead in pottery-glaze workers using micronucleus assay, alkaline comet assay and DNA diffusion assay

Purpose

We investigated genotoxic effects of occupational exposure to lead acetate in pottery-glaze ceramic workers.

Methods

The study was carried out in 30 exposed workers and 30 matched controls, to whom several biochemical parameters—the blood lead (B-Pb; range: exposed, 41.68–404.77; controls, 12–52) and cadmium (B-Cd) level, the activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), the level of vitamin B₁₂ and folate in serum—were measured. The genotoxic effects were evaluated by the alkaline comet assay, the DNA diffusion assay and micronucleus test in peripheral blood lymphocytes.

Results

Subjects exposed to lead had significantly higher B-Pb level and, consequently, increased values of tail intensity (TI), frequency of apoptotic and necrotic cells, and frequency of micronuclei (MN). In contrast, their activity of ALAD, the level of vitamin B₁₂ and folate in serum were significantly lower compared to controls. Poisson regression analysis showed a significant correlation of profession, duration of exposure, smoking, level of cadmium in blood, ALAD and EP with primary DNA damage. A majority of primary damage repairs in a short period after exposure to a genotoxic agent. In addition, the influence of gender and level of vitamin B₁₂ and folate in serum MN frequency in exposed group was observed.

Conclusions

In this study, DNA diffusion and micronucleus test showed higher influence of tested parameters to DNA damage. The results indicate a need for concomitant use of at least two different biomarkers of exposure when estimating a genetic risk of lead exposure.     

A Combination of Micronucleus Assay and Fluorescence In Situ Hybridization Analysis to Evaluate the Genotoxicity of Formaldehyde

A genotoxic effect of formaldehyde (FA), particularly micronucleus (MN) induction, has been shown in several previous studies. The aim of the present study was to assess the frequency of micronuclei and to identify the type of chromosomal damage in Tunisian staff members working in the Pathologic Anatomy Laboratory of Farhat Hached hospital (Sousse, Tunisia) who were exposed to FA. Assessment of chromosomal damage was performed in peripheral lymphocytes of 31 FA-exposed employees compared with 31 control employees working in the administrative department of the same hospital. The clastogenic/aneugenic effect of FA was evaluated using the standard MN assay in combination with fluorescence in situ hybridization (FISH) using pan-centromeric probes. The mean level of exposure to FA was 3.4 ppm. The results showed a significant increase of MN frequency in lymphocytes of exposed workers compared with the control group (25.35 ± 6.28 ‰ vs. 7.08  ± 4.62 ‰, p < 0.05). As assessed by FISH, the frequency of centromeric micronuclei (C+MN) was greater in exposed subjects than in controls (18.38 ± 5.94 ‰ vs. 5.03 ± 3.64 ‰). Among the C+MN, the frequency of MN containing one centromere (C1+MN) was significantly greater in pathologists and anatomists than in controls (15.35 ± 6.0 ‰ vs. 3.33 ± 2.74 ‰, p < 0.05). The results showed an effect of sex and time of FA exposure with significantly increased frequencies of all end points measuring aneuploidy (C+MN, C1+MN, and Cx+MN [more then one MN]). The increased frequency of C1+MN observed in the exposed group may suggest a slight aneugenic effect of FA exposure.     

Prevalence of respiratory symptoms and disorders among rice mill workers in India

Objectives

Lung function tests have become an integral part of assessment of pulmonary disease. Diseases of the respiratory system induced by occupational dusts are influenced by the duration of exposure. The aim of the study is to investigate the impairment of lung function and prevalence of respiratory symptoms among the rice mill workers.

Methods

A total of 120 rice mill workers from three districts of Karnataka were included in this study. Fifty urban dwellers from the same socio-economic level were selected as controls. The study included clinical examination, assessment of respiratory symptoms, pulmonary function test, measurement of peak expiratory flow rate, absolute eosinophil count, ESR estimation, total IgE estimation and radiographic test.

Results

The present study has shown that the rice mill workers complained of several types of respiratory disorders like phlegm (40.8 %), dyspnea (44.2 %), chest tightness (26.7 %), cough (21.7 %), and nose irritation (27.5 %). Rice mill workers exposed to dust presented significantly (p < 0.05) lower levels of FVC (3.44 ± 0.11), FEV₁ (2.73 ± 0.15) and PEFR (304.95 ± 28.79) than the controls. The rice mill workers are having significantly higher absolute eosinophil counts, total IgE and ESR than control groups. The hematological findings suggest that the harmful effects may be linked to both non-specific irritation and allergic responses to rice husk dust among rice mill workers.

Conclusion

Dust exposure in the working environment affects the lung function values and increased the respiratory symptoms among the rice mill workers.     

Inhalative Exposure to Vanadium Pentoxide Causes DNA Damage in Workers: Results of a Multiple End Point Study

Background

Inhalative exposure to vanadium pentoxide (V₂O₅) causes lung cancer in rodents.

Objective

The aim of the study was to investigate the impact of V₂O₅ on DNA stability in workers from a V₂O₅ factory.

Methods

We determined DNA strand breaks in leukocytes of 52 workers and controls using the alkaline comet assay. We also investigated different parameters of chromosomal instability in lymphocytes of 23 workers and 24 controls using the cytokinesis-block micronucleus (MN) cytome method.

Results

Seven of eight biomarkers were increased in blood cells of the workers, and vanadium plasma concentrations in plasma were 7-fold higher than in the controls (0.31 μg/L). We observed no difference in DNA migration under standard conditions, but we found increased tail lengths due to formation of oxidized purines (7%) and pyrimidines (30%) with lesion-specific enzymes (formamidopyrimidine glycosylase and endonuclease III) in the workers. Bleomycin-induced DNA migration was higher in the exposed group (25%), whereas the repair of bleomycin-induced lesions was reduced. Workers had a 2.5-fold higher MN frequency, and nucleoplasmic bridges (NPBs) and nuclear buds (Nbuds) were increased 7-fold and 3-fold, respectively. Also, apoptosis and necrosis rates were higher, but only the latter parameter reached statistical significance.

Conclusions

V₂O₅ causes oxidation of DNA bases, affects DNA repair, and induces formation of MNs, NPBs, and Nbuds in blood cells, suggesting that the workers are at increased risk for cancer and other diseases that are related to DNA instability.     

Assessment of construction workers’ hydration status using urine specific gravity

Objectives

The study objective was to assess hydration status by measuring USG among construction workers in Iran.

Materials and Methods

The study design was comparative and experimental. Sixty participants were randomly selected from the construction workers from a construction campus with a similar type of work, climate and diet and formed 2 groups (individuals exposed to the sun and non-exposed individuals). TWL and USG were measured in both groups on 2 consequent days, at the beginning, mid and end of the work shift.

Results

USG test showed that mean USG was 1.0213±0.0054 in the control group and in the exposed group, where it was significantly higher, it amounted to 1.026±0.005. In the exposed group, 38% of workers had a USG level between 1.026–1.030, representing a higher risk of heat illness and impaired performance and 12.72% had a USG level above 1.030 representing a clinically dehydrated status, while this proportion in the control group was 15.2% and 0.58%, respectively. The mean TWL index measure was 215.8±5.2 W/m2 for the control group and 144±9.8 W/m2 for the exposed group, where, again, it was significantly higher. The Pearson correlation measure showed a significant correlation between USG and TWL.

Conclusions

Strong correlation between TWL, as an indicator of thermal stress and USG shows that USG can be considered as a predictor of thermal stress. The difference between USG among the exposed and non-exposed workers and the increase in USG during midday work show the sensitivity of this measure in different thermal and climatic conditions, whereas, the high level of dehydration among workers despite acceptable TWL level, shows that heat stress management without considering the real hydration status of workers, is insufficient.     

Heart rate variability (HRV) analysis in radio and TV broadcasting stations workers

Objectives

The aim of the study was to assess the mechanism of cardiovascular impairments in workers exposed to UHF-VHF radio frequency electromagnetic fields (EMF).

Materials and Methods

Heart rate variability (HRV) was analysed using 512 normal heart beats registered at rest. The analysis concerned time-domain (STD R-R) and frequency-domain (VLF, LF, HF) parameters of HRV. Fifty nine workers (group I) with low-level and 12 workers (group II) with high-level exposure were examined. The mean age of the subjects was 47±9 years and 41±14 years, and mean exposure duration 19.1±8.8 years and 13±4 years, in groups I and II, respectively. The groups were divided according to: E_max, E_dose, E_mean for frequencies UHF, VHF and UHF+VHF: The control group consisted of 42 non-exposed subjects, aged 49±8 years. Statistical analysis comprised one-way analysis of variance, covariance analysis and logistic regression models.

Results

In the exposed groups, the heart rate was higher than in the control one. Standard deviation of R-R intervals (STD R-R) was found to be significantly (p = 0.0285) lower in group I (42.5±24.7 ms) compared to the control group (62.9±53.5 ms). The risk of lowered STD R-R was significantly increased (OR = 2.37, p = 0.023) in group II. Both exposed groups presented significantly higher VLF and LF values than the control group (p = 0.005 and p = 0.0025, respectively). The EMF-exposed groups were characterised by the dominance of the sympathetic system (LF/HF 1.3±0.35).

Conclusions

The results indicate that exposure to radiofrequency EMF may affect the neurovegetative regulation.     

Cardiovascular changes in workers exposed to fine particulate dust

Objectives

Epidemiological studies provide evidence that airborne particulate matter may contribute to the increased incidence and mortality rates due to pulmonary and cardiovascular diseases. Only some of them address the problem of occupational exposure to particulate air pollution. The aim of our study was to assess cardiovascular reaction and autonomic regulation in workers exposed to fine particles.

Materials and Methods

All workers had medical examination, resting ECG with heart rate variability analysis (HRV), 24-h ECG, and ambulatory blood pressure monitoring (ABPM) performed. The subjects were 20 male workers (mean age: 32.14.0 year) of a ceramic ware factory exposed to the dust and 20 workers who were not exposed (mean age: 39.4±7.8 year). The period of employment under exposure amounted to 5.6±2.1 year. Dust exposure was measured using individual dosimeters.

Results

The geometric mean total dust concentration was 44±1.5 mg/m³ and the FPD (fine particulate dust) concentration amounted to 11.5±1.6 mg/m³. No abnormalities were noted in the resting ECG in both groups, in 24-h ECG 2 subjects, both from exposed and control groups, had ventricular heart rhythm and repolarization disturbances. Blood pressure in ABPM, both systolic as well as diastolic, was normal and did not differ between the groups. Resting heart rate in the exposed group was significantly lower (p = 0.038) than in the control group. In the exposed group STD R-R from short-term records was significantly higher (p = 0.01). Fast Fourier Transform (FFT) analysis showed that the low frequency power spectrum (LF) did not differ in the exposed and the control group, while high frequency (HF) was significantly higher in the exposed group. LF/HF ratio was significantly lower in the exposed in comparison with the control group.

Conclusions

Although we did not reveal significant abnormalities in ECG as well as in ABPM in the exposed group, it seems that neurovegetative disturbances (parasympathetic predominance) may serve as an early indicator of fine particulate dust effect on cardiovascular system.     

Correlation of chromosome damage and promoter methylation status of the DNA repair genes MGMT and hMLH1 in Chinese vinyl chloride monomer (VCM)-exposed workers

Objective

To explore the association of the methylation status of MGMT and hMLH1 with chromosome damage induced by vinyl chloride monomer (VCM).

Materials and Methods

Methylation of MGMT and hMLH1 was measured in 101 VCM-exposed workers by methylation-specific PCR. Chromosome damage in peripheral blood lymphocytes was measured by the cytokinesis-block micronucleus assay. The subjects were divided into chromosome damaged and non-damaged groups based on the normal reference value of micronuclei frequencies determined for two control groups.

Results

MGMT promoter methylation was detectable in 5 out of 49 chromosome damaged subjects, but not in the chromosome non-damaged subjects; there was a significant difference in MGMT methylation between the two groups (p < 0.05).

Conclusions

We detected aberrant promoter methylation of MGMT in a small number of chromosome damaged VCM-exposed workers, but not in the chromosome non-damaged subjects. This preliminary observation warrants further investigation in a larger study.     

Leisure-time physical activity does not fully explain the higher body mass index in irregular-shift workers

Purpose

To elucidate the influence of leisure-time physical activity on body mass index (BMI), appetite-related hormones, and sleep when working irregular shifts.

Methods

A cross-sectional study was undertaken of 57 male truck drivers, 31 irregular-shift workers and 26 day-shift workers. Participants completed the International Physical Activity Questionnaire and were assessed for BMI. Subjects also provided a fasting blood sample for analysis of appetite-related hormones and wore an actigraphy device for seven consecutive days.

Results

Although leisure-time physical activity (LTPA) was generally low (<150 min/week) in both groups, the irregular-shift workers were more physically active than day-shift workers (99 ± 166 vs. 23 ± 76 min/week, p < 0.01). In spite of this, mean BMI of irregular-shift workers was 2 kg/m² greater than day-shift workers (28.4 ± 3.8 vs. 26.4 ± 3.6 kg/m², p = 0.04). Mean leptin concentration was 61 % higher in irregular-shift workers (5,205 ± 4,181 vs. 3,179 ± 2,413 pg/ml, p = 0.04). Among obese individuals, irregular-shift workers had higher leptin concentration (p < 0.01) and shorter sleep duration (p = 0.01) than obese day-shift workers.

Conclusion

Elevated BMI was associated with high leptin and low ghrelin levels in this population of irregular-shift workers. No influence of LTPA on appetite-related hormones or sleep duration was found. We conclude that moderate LTPA is insufficient to attenuate the higher BMI associated with this type of irregular-shift work in truck drivers.     

Emotional demands and the risks of depression among homecare workers in the USA

Purpose

Homecare workers’ diversity of emotional demands and their relation to mental health problems have not yet been fully explored. The purpose of this study is to investigate the types of emotional demands on homecare workers and the association of these demands with depression.

Method

Data were collected from two surveys of a random sample of 1,599 homecare workers (June 2003–September 2003 and December 2003–February 2004). Depression was assessed using a 20-item RCES-D screening scale.

Results

Homecare workers appeared to have a variety of emotional demands: unfair treatment, client’s family abuse, unmet care needs, client health, and emotional suppression. In general, homecare workers were more likely to be exposed to their client health and emotional suppression (mean scores = 1.46–3.07) than to be exposed to unmet care needs, unfair treatment, and client’s family abuse (mean scores = 1.02–1.38). After adjusting for potential confounders, four emotional-demand factors (excluding the client health factor) were significantly associated with a high risk of subthreshold depression at Wave 1. In particular, the factor “unmet care needs” was an essential predictor of 6-month subthreshold depression at Wave 2.

Conclusion

This study illustrated the diversity of emotional demands among homecare workers and their association with depression. Our mixed findings regarding the cross-sectional and longitudinal analyses suggested that further research should refine the measurement of emotional demands and their relationship with mental health among homecare workers.     

介入放射工作人员染色体畸变和微核观察

目的 探讨X射线对介入放射工作者外周血淋巴细胞染色体和微核的影响，确保介入放射工作人员的健康与安全。方法 选择363名从事介入放射学的工作人员作为研究对象，未接触电离辐射的435名健康从业人员为对照组，采取微量全血培养法对外周血淋巴细胞染色体和微核进行培养、检测和分析。结果 介入放射组的淋巴细胞染色体总畸变率（0.11% ±0.373%）显著高于对照组（0.02% ±0.126%），结果差异有统计学意义（t = 5.080, P< 0.01）；无着丝粒体率（0.04% ±0.199%）和双着丝粒体率（0.06%±0.234%），也明显高于对照组（0.01% ±0.107%）、（0.00% ±0.068%），差异均有统计学意义（t = 2.693，4.529，P 均< 0.01）；微核率（0.78‰ ±0.996‰）与对照组（0.65‰ ±0.853‰）比较，差异亦有统计学意义（t = 2.000，P< 0.05）。不同工龄间的染色体畸变率、无着丝粒体率和双着丝粒体率差异均无统计学意义（P > 0.05）；微核率的差异具有统计学意义（P < 0.01）。其中工龄 ≥ 20a工龄组与其他组的微核率差异有统计学意义（P < 0.01）。介入组与普通放射组（放射诊断、放射治疗、工业应用）相比，染色体总畸变率、双着丝粒体率差异均具有统计学意义（P < 0.01，P < 0.05），组间两两比较，介入组染色体总畸变率（0.10% ±0.299%）显著高于放射诊断（0.06% ±0.312%）、放射治疗（0.03% ±0.170%）和工业应用组（0.04% ±0.189%），差异均有统计学意义（P < 0.01）；介入组染色体双着丝粒体率（0.06% ±0.234%）亦显著高于放射诊断（0.03% ±0.239%）、放射治疗（0.01% ±0.121%）和工业应用组（0.02% ±0.135%），差异均有统计学意义（P< 0.05）；介入组与各组之间的染色体无着丝粒体率和微核率差异无统计学意义。结论 X射线对介入放射工作人员染色体畸变率及微核率有一定的影响。长期接触低剂量的电离辐射，可以导致外周血淋巴细胞染色体畸变率和微核率显著增加，并随着工作年龄的增加而逐渐增加。     

Initiation of health-behaviour change among employees participating in a web-based health risk assessment with tailored feedback

Background

Biological monitoring of healthy workers exposed to hazardous dusts lack validated screening tools. Induced sputum (IS) cellular profile was compared with bronchoalveolar lavage fluid (BALF) profile in asbestos exposed workers in order to assess its usefulness in monitoring workers exposed to asbestos for a long period of time.

Methods

IS and BALF analysis was performed in 39 workers of a car brakes and clutches factory that uses chrysotile asbestos. Selection criteria were an employment history of > 15 years and the absence of a diagnosis of pneumonoconiosis. The type of cells, the existence of dust cells, of iron laden macrophages and of asbestos bodies were assessed and compared between IS and BALF samples.

Results

35 IS samples (90%) had dust cells, 34 (87%) iron laden macrophages and in 8 samples (21%) asbestos bodies were found. In most samples neutrophils were dominated. Samples with asbestos bodies (ABs) had significantly higher lymphocytes and lower neutrophils count compared with the samples without ABs. Macrophages and neutrophils in IS and BALF exhibited significant inter-relations (Spearman's rho: 0.26-0.29, p < 0.05) while IS lymphocytes count showed an inverse relation with BALF neutrophils (Spearman's rho: -0.36). Neutrophils and dust cells were highly correlated between the samples (Spearman's rho: 0.35, p < 0.05) while IS dust cells and lymphocytes were inversely related (Spearman's rho: -0.36, p < 0.05). More years of employment in the company was related with more neutrophils (Spearman's rho: 0.26) and less lymphocytes (Spearman's rho: -0.33) count. In multivariate analysis the presence of AB in IS samples was strongly related to the presence of asbestos bodies and lymphocytes count in BALF samples.

Conclusions

IS and BALF analysis showed a similar cellular profile indicating that IS sampling in exposed workers to asbestos as a less invasive and expensive method may be useful in providing an insight both for inhalation of dusts and inflammatory processes in the lung.     

Comparison of urinary thallium levels in non-occupationally exposed people and workers

Purpose

To determine a reference background urinary thallium level; to compare urinary thallium data from workers to this background level; to investigate factors affecting these levels and whether creatinine correction is appropriate.

Methods

Urine samples from non-occupationally exposed people (n = 273, from 113 individuals) and workers (n = 896, from 447 individuals) were analysed for thallium by ICP-MS. A reference background level was calculated, defined as the 95th percentile value of a non-occupationally exposed population. Worker data were divided into two subsets: thallium workers (those who work directly with thallium or its compounds) and general workers; and compared to the background level. Bayesian linear mixed effects modelling was used to investigate factors affecting urinary thallium concentration and the efficacy of creatinine correction for the determination of urinary thallium.

Results

The reference background urinary thallium level is 0.27 μmol/mol creatinine (creatinine-corrected) or 0.40 μg/l (uncorrected). Median values were 0.11 μmol/mol creatinine or 0.17 μg/l for non-occupationally exposed people, 0.12 μmol/mol creatinine or 0.20 μg/l for general workers and 0.19 μmol/mol creatinine or 0.41 μg/l for thallium workers. Variation was lower in creatinine-corrected models. Nine per cent of samples from general workers and 39 % of samples from thallium workers exceeded the creatinine-corrected background level. By 2010, 90 % of all workers had urinary thallium levels below the 95th percentile reference background level.

Conclusions

Urinary thallium concentrations were higher in thallium workers than non-occupationally exposed people and general workers. Creatinine correction is appropriate.     

全自动染色体收获仪在淋巴细胞微核试验中的价值

目的 探讨全自动染色体收获仪在淋巴细胞微核试验中的优势。方法 采集80名放射工作人员的外周血,分别用全自动染色体收获仪和手工法收获淋巴细胞,吉姆萨染片后,在显微镜下观察淋巴细胞的微核。结果 对同一批标本收获淋巴细胞,全自动收获仪用时（185 min）小于人工组（350 min）,使用收获仪得到的微核率（1.04‰ ±0.63‰）、微核细胞率（0.89‰ ±0.69‰）和微核阳性率（70.0%）均高于手工法（0.60‰ ±0.68‰,0.51‰ ±0.55‰,48.8%）,差异均有统计学意义（P < 0.01）。结论 全自动染色体收获仪可以缩短实验操作的时间,减轻实验室人员的工作量,保护实验人员的身心健康;同时提高淋巴细胞微核的检出率,为临床提供更为准确的检测数据。     

Effect of fire smoke on some biochemical parameters in firefighters of Saudi Arabia

Background

Lead exposure is common in automobile battery manufacture and repair, radiator repair, secondary smelters and welding units. Urinary Aminolevulinic acid has validity as a surrogate measure of blood lead level among workers occupationally exposed to lead. This study had therefore assessed the magnitude of lead exposure in battery repair workers of three transport service enterprises.

Methods

To this effect, a cross-sectional study was carried out on lead exposure among storage battery repair workers between November 2004 and May 2005 from Anbasa, Comet and Walia transport service enterprises, Addis Ababa, Ethiopia. Subjective information from the workers was obtained by making use of structured questionnaire. Other information was obtained from walkthrough evaluation of the repair units. Aminolevulinic acid levels in urine were used as an index of the exposure. This was coupled to measurements of other relevant parameters in blood and urine collected from adult subjects working in the repair units as well as age matched control subjects that were not occupationally exposed to lead. Aminolevulinic acid was determined by spectrophotometry, while creatinine clearance, serum creatinine, urea and uric acid levels were determined using AMS Autolab analyzer.

Results

Urinary aminolevulinic acid levels were found to be significantly higher in exposed group (16 μg/ml ± 2.0) compared to the non-exposed ones (7 μg/ml ± 1.0) (p < 0.001). Alcohol taking exposed subjects exhibited a significant increase in urinary aminolevulinic acid levels than non-alcohol taking ones (p < 0.05). Moreover, urinary aminolevulinic acid levels of exposed subjects increased with age (p < 0.001) as well as duration of employment (p < 0.001). Whereas serum uric acid levels of exposed subjects was significantly higher than non-exposed ones (p < 0.05), no statistically significant difference had been found in renal indices and other measured parameters between exposed and non-exposed subjects. From the questionnaire responses and walkthrough observations, it was also known that all the repair units did not implement effective preventive and control measures for workplace lead exposure.

Conclusion

Taken together, these findings indicated that workers in lead acid battery repair units of the transport service enterprises are not protected from possibly high lead exposure. Thus, strict enforcement of appropriate and cost effective preventive and control measures is required by all the enterprises.     

Exposure to disturbing noise and risk of long-term sickness absence among office workers: a prospective analysis of register-based outcomes

Purpose

To investigate the association between self-reported exposure to disturbing noise and risk of long-term sickness absence (LTSA) for more than two consecutive weeks among office workers.

Methods

LTSA was measured using register data that were linked to survey data from 2,883 office workers aged 18–59 who were surveyed in 2005 on exposure to disturbing noise. The risk of LTSA was investigated using Cox proportional hazards model.

Results

Of the study population, 4.4 % had LTSA in the 1-year follow-up period. Compared to office workers who were ‘rarely or never’ exposed to disturbing noise at work, office workers who reported being ‘frequently’ exposed to disturbing noise had a significantly increased estimated risk of LTSA when adjusting for age, gender, smoking status, and managerial position (HR = 1.90; 95 % CI, 1.12–3.22). After additional adjustment for psychosocial work conditions, the estimated risk of LTSA for office workers who were frequently exposed to disturbing noise became marginally insignificant (HR = 1.73; 95 % CI, 0.99–3.01). A subgroup analysis showed that women who reported being frequently exposed to disturbing noise had a significantly increased estimated risk of LTSA (HR = 1.94; 95 % CI, 1.04–3.64), whereas the corresponding risk for men was insignificant (HR = 1.28; 95 % CI, 0.37–4.41).

Conclusions

This study indicates that frequent self-reported exposure to disturbing noise at work is associated with increased risk of LTSA among office workers and that this association may be stronger for women than for men.     

Electronic noses for monitoring benzene occupational exposure in biological samples of Egyptian workers

Objectives

Benzene is commonly emitted in several industries, leading to widespread environmental and occupational exposure hazards. While less toxic solvents have been substituted for benzene, it is still a component of petroleum products and is a trace impurity in industrial products resulting in continued higher occupational exposures in industrial settings in developing countries.

Materials and Methods

We investigated the potential use of an electronic nose (e-nose) to monitor the headspace volatiles in biological samples from benzene-exposed Egyptian workers and non-exposed controls. The study population comprised 150 non-smoking male workers exposed to benzene and an equal number of matching non-exposed controls. We determined biomarkers of benzene used to estimate exposure and risk including: benzene in exhaled air and blood; and its urinary metabolites such as phenol and muconic acid using gas chromatography technique and a portable e-nose.

Results

The average benzene concentration measured in the ambient air of the workplace of all studied industrial settings in Alexandria, Egypt; was 97.56±88.12 μg/m³ (range: 4.69–260.86 μg/m³). Levels of phenol and muconic acid were significantly (p < 0.001) higher in both blood and urine of benzene-exposed workers as compared to non-exposed controls.

Conclusions

The e-nose technology has successfully classified and distinguished benzene-exposed workers from non-exposed controls for all measured samples of blood, urine and the exhaled air with a very high degree of precision. Thus, it will be a very useful tool for the low-cost mass screening and early detection of health hazards associated with the exposure to benzene in the industry.     

Polymorphisms in the p53 pathway genes and micronucleus occurrence in Chinese vinyl chloride-exposed workers

Objectives

To investigate the association between polymorphisms in the p53 pathway genes and chromosomal damage in vinyl chloride (VC)-exposed workers.

Materials and Methods

Cytokinesis block micronucleus test was performed in 310 VC-exposed workers and 149 non-exposed workers to determine chromosomal damage. The polymerase chain reaction and restriction fragment length polymorphism technique were used to detect six SNPs in the p53 pathway genes involved in the cell cycle.

Results

There was a highly significant dose-response relationship between VC exposure and chromosomal damage. Individuals carrying the variant genotypes were at higher risk for chromosomal damage compared with their wild type genotype: p53rs1042522, MDM2 Del1518rs3730485, MDM2rs2279744 and GADD45Ars532446. On the other hand, individuals possessing the variant genotype of CDKN2A rs3088440 had significantly decreased risk compared with the corresponding wild-type.

Conclusions

Genetic polymorphisms in P53 pathway genes may have an impact on VC-induced chromosomal damage.