Biological monitoring of occupational exposure to toluene diisocyanate

Summary The study validated the use of urinary toluene diamine (TDA) in postshift samples as an indicator of preceding 8-h exposure to toluene diisocyanate (TDI). Nine workers exposed in TDI-based polyurethane foam production were studied. Their exposure levels varied in 8-h time-averaged samples from 9.5 to 94 g/m³. The urinary TDA concentrations varied from 6.5 to 31.7g/g creatinine and they were linearly related to the atmospheric TDI levels. Approximately 20% of TDI is metabolized to diamines but their specificity is remarkable to the extent that by analysis for the 2,4- and 2,6-diamino isomers an idea of the percutaneous absorption may be had.     

On the need of a sampling strategy in biological monitoring: The example of hexane exposure

Ambient and biological monitoring of hexane exposure were repeatedly carried out in 14 female shoe makers. Airborne hexane (Ci-H) was measured in 4-h samples collected by a diffusive method. Urinary spot samples were collected before, during (at noon), and at the end of a work shift. 2,5-Hexanedione (2,5HD) in urine collected at noon was poorly related to morning Ci-H. End-of-shift 2,5HD were also poorly related to afternoon air samples. The correlation was still relatively low when end-of-shift 2,5HD was related to 8-h TWA Ci-H (r= 0.44; P<0.01 on=" a=" linear=" scale,=" and=">r-0.58, P< 0.01=" on=" a=" log-log=" scale).=" end-of-shift=" 2,5hd=" levels=" estimated=" on=" the=" basis=" of=" pre-shift=" values=" using=" a=" mathematical=" model=" were=" much=" higher=" (2.3=" times=" on=" average)=" than=" those=" experimentally=" measured=" during=" the=" study=" period.=" owing=" to=" its=" relatively=" long=" half-time,=" 2,5hd=" seems=" to=" be=" influenced=" not=" only=" by=" current=" exposure,=" but=" also=" by=" hexane=" absorbed=" during=" the=" day(s)=" preceding=" sampling.=" the=" lack=" of=" a=" sampling=" strategy=" may=" account=" not=" only=" for=" inconsistencies=" between=" environmental=" and=" biological=" data,=" but=" also=" for=" a=" possible=" misuse=" of=" biological=" monitoring=" when=" utilized=" for=" risk=" assessment.=" despite=" sometimes=" poor=" correlations=" with=" ci-h,=" 2,5hd=" may=" still=" be=" preferred=" to=" other=" indicators=" as=" a=" marker=" of=" effective=" internal=" dose.=" a=" sampling=" strategy=" should=" ensure=" that=" measured=" values=" are=" representative=" of=" the=" individual=" risk=" for=" adverse=">     

Cancer risk assessment for health care workers occupationally exposed to cyclophosphamide

In the present study a cancer risk assessment of occupational exposure to cyclophosphamide (CP), a genotoxic carcinogenic antineoplastic agent, was carried out following two approaches based on (1) data from an animal study and (2) data on primary and secondary tumors in CP-treated patients. Data on the urinary excretion of CP in health care workers were used to estimate the uptake of CP, which ranged from 3.6 to 18 g/day. Based on data from an animal study, cancer risks were calculated for a health care worker with a body weight of 70 kg and a working period of 40 years, 200 days a year (linear extrapolation). The lifetime risks (70 years) of urinary bladder cancer in men and leukemias in men and women were found to be nearly the same and ranged from 95 to 600 per million. Based on the patient studies, cancer risks were calculated by multiplication of the 10-year cumulative incidence per gram of CP in patients by the estimated mean total uptake in health care workers over 10 years, 200 days a year. The risk of leukemias in women over 10 years ranged from 17 to 100 per million using the secondary tumor data (linear extrapolation). Comparable results were obtained for the risk of urinary bladder tumors and leukemias in men and women when primary tumor data were used. Thus, on an annual basis, cancer risks obtained from both the animal and the patient study were nearly the same and ranged from about 1.4 to 10 per million. In The Netherlands it is proposed that, for workers, a cancer risk per compound of one extra cancer case per million a year should be striven for (target risk) and that no risk higher than 100 per million a year (prohibitory risk) should be tolerated. From the animal and the patient study it appears that the target risk is exceeded but that the risk is still below the prohibitory risk.     

职业人群不健康行为生活方式与高尿酸血症的关系及高血压、血脂异常的效应修饰作用

目的 探索不健康行为生活方式与高尿酸血症的关系,以及高血压、血脂异常的效应修饰作用,为预防高尿酸血症提供理论依据。方法 采用横断面调查研究设计,基于2021年10-12月来自四川省、贵州省28个地级市和重庆市33个区（县）中国铁路成都局集团有限公司的西南职业人群队列基线数据,通过问卷调查、体格测量及实验室生化检测收集研究对象的人口学特征、行为生活方式、慢性非传染性疾病患病情况。不健康行为生活方式得分根据吸烟、饮酒、膳食模式、体力活动和低体重/超重状况进行评分,分值越高不健康行为生活方式越多。采用多因素logistic回归模型分析不健康行为生活方式评分、吸烟状况、饮酒状况等与高尿酸血症的关系,采用分层分析探索高血压等疾病对不健康行为生活方式与高尿酸血症之间关系的修饰效应。结果 共纳入11 748名研究对象,高尿酸血症患病率为34.4%。多因素logistic回归分析显示,现在吸/既往吸烟、现在饮/既往饮酒及BMI异常是高尿酸血症患病的危险因素,不健康行为生活方式对高尿酸血症患病风险呈现累积效应,随着得分的升高,高尿酸血症患病风险升高,OR值由1.64（95%CI：1.34~2.00）上升至2.89（95%CI：2.39~3.50）。分层分析结果显示,在高血压及血脂异常人群中,不健康行为生活方式对高尿酸血症患病风险影响更大。结论 多种不健康行为生活方式的共存会升高高尿酸血症患病风险,这一效应在高血压、血脂异常人群中更明显。及时纠正不健康行为生活方式,并控制高血压和血脂异常,降低患高尿酸血症的风险。     

Transient decrease in sound tolerance levels following hearing deprivation in normal-hearing subjects

ObjectiveTo determine the circadian influence on sound sensitivity produced by temporal hearing deprivation in healthy normal human subjects.DesignParticipants underwent bilateral earplugging before completion of anthropometry, the author's developed questionnaire, the Hamilton Anxiety and Depression Inventory, pure tone audiometry (PTA), stapedial reflex thresholds (SRT), distortion products otoacoustic emissions input/output (DPOAE-I/O), and uncomfortable loudness levels (ULLs). Afterward, the participants were randomly divided into group A, starting at 8:00 a.m. and finishing at 8:00 p.m., and group B, starting at 4:00 p.m. and ending at 4:00 a.m. Serum cortisol levels and audiological test results were obtained at the beginning and end of the session and 24-h free urinary cortisol levels were measured.Study sampleThirty healthy volunteers.ResultsPTA was 2.68 and 3.33 dB HL in groups A and B, respectively, with no statistical difference between them. ULLs were significantly lower in group A compared to group B, with an average of 8.1 dB SPL in group A and 3.3 dB SPL in group B (p < 0.0001). A SRT shift was observed in group A, with no difference in group B, and a night shift in DPOAE-I/O in group B.ConclusionsReduced loudness tolerance is demonstrated during daytime hearing deprivation in contrast to nighttime; this may be due to increased central gain in the awake cortex.     

The epidemiology of occupational contact dermatitis

Occupational contact dermatitis (OCD) ranks first of all occupational diseases in many countries. The incidence rate is believed to be around 0.5–1.9 cases per 1000 full-time workers per year. Epidemiological studies play an important role in observing disease trends, analysing risk factors, and monitoring the effect of preventive measures. In this review article the lack of truly epidemiologic data on OCD and the difficulties of those studies are illustrated. The following issues are highlighted: case ascertainment and bias, the distribution of allergic and irritant contact dermatitis in the working population, the interrelationship between exogenous (allergens, irritants) and endogenous factors, the prognosis, the social and economic impact, and the need for intervention studies. Received: 26 January 1999 / Accepted: 24 April 1999     

橡胶职业暴露与多种疾病关系研究的死因别危险度联合分析模型

应用Ｃｏｘ回归风险度模型,进行了死因别（肺癌,肠癌和胰腺癌,及心脑血管疾病）联合分析,以便估计和检验橡胶化合物暴露对特定死因别的效应,以及死因间竞争性危险度。结果表明：心脑血管疾病可能对肺癌、肠癌和胰腺癌产生了竞争性死亡的效应。亚硝胺暴露的３类死因别危险度之间有显著性差别,表现为肺癌危险度最高。其他４种橡胶化合物的死因别危险度之间差别不显著。这些结果有力地证实了亚硝胺与肺癌的联系。     

Effect of occupational mercury exposure on plasma lysosomal hydrolases

Summary The activities of three plasma lysosomal hydrolases, -galactosidase, -glucuronidase and -N-acetylglucosaminidase, were studied in 20 workers exposed to metallic mercury vapor in a chlorine alkali plant and in 10 nonexposed referents. The urinary excretion and blood levels of mercury were determined on the day of study, and the history of mercury exposure was reviewed from the records of mercury concentrations in urine and blood over periods of up to 133 months. The average levels of -N-acetylglucosaminidase and -glucuronidase were higher in the plasma of exposed workers, but the difference was not significant. No significant positive correlation was seen between lyosomal enzyme activities and cumulative long-term exposure to mercury. It is concluded that measurement of plasma lysosomal hydrolase-activities is not of great value in the biological monitoring of workers exposed to low concentrations of metallic mercury vapor.In line with published data, the concentration of mercury showed a clearcut diurnal variation in nonexposed persons, persons currently exposed and persons with a history of past exposure. The excretion rate of mercury remained constant throughout the day.     

The applicability of the measurement of urinary thioethers

Summary The excretion of thioethers was measured in the urine of 6 volunteers, who were experimentally exposed to styrene, and 18 styrene workers. In addition, 12 clerks (non-smokers) and 12 sheet-metal workers (smokers) served as control groups. Diet was standardized during the experiments. Thioethers were measured by a spectrophotometric method. The volunteers were exposed to styrene, 210 mg/m³, for 2 h at a 50-W workload. An increase in thioether excretion was observed; the largest was in the urine samples collected between 0.5 and 5 h after the end of the exposure. After 43 h the excretion of thioethers was close to the preexposure level (3.5 mmol/mol creatinine). About 1% of the styrene absorbed was detected as thioethers in urine, which is only about 1/10 of the conversion reported for rats. From excretion rate curves a half-life of about 11 h was calculated for styrene thioethers. The styrene workers were employed at two plants. The average exposure to styrene (time-weighted average 8 h) was estimated to be about 115 mg/m3 (smokers in plant A), 55 mg/m³ (non-smokers in plant A) and 10 mg/m³ (non-smokers in plant B). The excretion of thioethers in exposed workers at plant A was higher by 2–4 mmol/mol creatinine than that in non-exposed controls. In plant B, where exposure was lower, an increase in that amount of thioethers excreted in the urine by exposed workers was less pronounced, and was statistically significant only when post-shift samples were compared with pre-shift samples. The results of the present study indicate that control samples should be collected both from non-exposed groups and from the exposed individuals before work shifts, to improve the likelihood of detecting genotoxic exposure in the work environment.