Deschamps D, Garnier R, Lille F
… +4 more, Tran Dinh Y, Bertaux L, Reygagne A, Dally S
Br J Ind Med
· 1993 Apr · PMID 8494772
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Epidemiological studies have provided evidence that neuropsychiatric symptoms are induced by long term exposure to solvents; individual diagnosis with psychometric tests, however, is not always possible (for example, whe...Epidemiological studies have provided evidence that neuropsychiatric symptoms are induced by long term exposure to solvents; individual diagnosis with psychometric tests, however, is not always possible (for example, when the patient has linguistic difficulties). Therefore evoked potentials and cerebral blood flow were studied in 50 patients occupationally exposed to solvents who were referred to our department and for whom a solvent induced psycho-organic syndrome was suspected. Degree of exposure was evaluated by its duration (mean 13.9, range 1 to 37 years) and its intensity (from an interview). At the group level, P22 and N35 latencies and amplitude N20-P22 of somatosensory evoked potentials were higher in cases than in controls (p < 0.05), whereas there was no difference for brainstem and visual evoked potentials, nor for hemispheric cerebral blood flow (but a higher distribution in the left occipital region was seen in patients, p < 0.05). Some parameters were linked to degree of exposure (amplitude N20-P22 of somatosensory evoked potentials, interpeak latency I-V of brainstem evoked potentials, distribution of cerebral blood flow in the internal frontal left region). At the individual level, these examinations were not of diagnostic value because sensitivity was low.
Bisanti L, Maggini M, Raschetti R
… +5 more, Alegiani SS, Ippolito FM, Caffari B, Segnan N, Ponti A
Br J Ind Med
· 1993 Apr · PMID 8494771
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A cohort of 1971 chemical workers licensed to handle ethylene oxide was followed up retrospectively from 1940 to 1984 and the vital status of each subject was ascertained. No quantitative information on exposure was avai...A cohort of 1971 chemical workers licensed to handle ethylene oxide was followed up retrospectively from 1940 to 1984 and the vital status of each subject was ascertained. No quantitative information on exposure was available and therefore cohort members were considered as presumably exposed to ethylene oxide. The cohort comprised 637 subjects allowed to handle only ethylene oxide and 1334 subjects who obtained a licence valid for ethylene oxide as well as other toxic gases. Potential confounding arising from the exposure to these other chemical agents was taken into consideration. Causes of death were found from death certificates and comparisons of mortality were made with the general population of the region where cohort members were resident. Seventy six deaths were reported whereas 98.8 were expected; the difference was statistically significant. The number of malignancies for any site exceeded the expected number (standardised mortality ratio (SMR) = 130; 43 observed deaths; 95% confidence interval (95% CI) 94-175) and approached statistical significance. For all considered cancer sites the SMRs were higher than 100 but the excess was only significant (p < 0.05, two sided test) for lymphosarcoma and reticulosarcoma (International Classification of Diseases--9th revision (ICD-9) = 200; SMR = 682; four observed deaths; 95% CI 186-1745). The excess of cases for all cancers of haematopoietic tissue (ICD-9 = 200-208) also approached statistical significance (SMR = 250; six observed deaths; 95% CI 91-544). Focusing the analysis on the subcohort of the ethylene oxide only licensed workers, who are likely to have experienced a more severe exposure to this gas, it became evident that all but one of the observed cases of haematopoietic tissue cancers in the cohort were confined to this subgroup, enhancing the relevant SMR to 700 (95% CI 237-1637) and the SMR of lymphosarcoma and reticulosarcoma to 1693 (95% CI 349-4953).
Br J Ind Med
· 1993 Apr · PMID 8494770
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This epidemiological study was of 18,728 employees at 14 United States facilities producing sterilised medical supplies and spices, who were potentially exposed to ethylene oxide (EO) for at least 90 days. The mortality...This epidemiological study was of 18,728 employees at 14 United States facilities producing sterilised medical supplies and spices, who were potentially exposed to ethylene oxide (EO) for at least 90 days. The mortality of the cohort was studied to the end of 1988. A total of 1353 deaths was identified. The cohort had a significantly lower mortality than the general population from all causes, all cancers, and non-malignant diseases. In the entire cohort, mortality was not significantly increased from any of the cancer sites examined. In particular, no significant increase in mortality was found in the cancer sites of interest based on previous studies--namely, stomach, leukaemia (including major specific cell types), pancreas, and brain. The lack of an increased mortality for these cancer sites was further strengthened by the lack of a dose-response relation with duration of employment and latency. Among the men, a statistically significant increase in mortality from non-Hodgkin's lymphoma was found. There was no indication for a dose-response relation for non-Hodgkin's lymphoma and no specific job categories seemed to be responsible for the increase. Among the women, a deficit of non-Hodgkin's lymphoma was found, which was not consistent with the finding in the men. Therefore, the increase among the men did not seem to be related to exposure to EO.
Br J Ind Med
· 1993 Apr · PMID 8388242
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There is considerable experimental evidence that asbestos fibres are taken up by epithelial cells, and that uptake of fibres is associated with various deleterious, particularly mutagenic, effects. It is not known, howev...There is considerable experimental evidence that asbestos fibres are taken up by epithelial cells, and that uptake of fibres is associated with various deleterious, particularly mutagenic, effects. It is not known, however, if asbestos fibres are taken up by human bronchial epithelial cells in vivo. To investigate this question, the amosite asbestos content of the mucosa of seven different airways and four parenchymal sites supplied by these airways in six necropsy lungs from heavily exposed never-smoking long term shipyard and insulation workers without asbestosis was examined. Amosite asbestos was readily found in moderately high concentration in all parenchymal samples, but 33 of 40 airway samples that could be evaluated showed no amosite fibres. The seven positive airways had fibre concentrations that were always much lower than the parenchymal concentrations, and these very few fibres may have been contaminants from the parenchyma. These data suggest that, at least in non-smokers, amosite asbestos either does not penetrate into or does not accumulate in human airway mucosa. These findings also call into question the idea that asbestos acts as a direct airway carcinogen in humans.
Br J Ind Med
· 1993 Apr · PMID 8388241
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Neurotoxic effects associated with long term low level occupational exposure to CS2 were reinvestigated four years after the initial study in the same group of workers. The second study concerned 44 exposed and 31 matche...Neurotoxic effects associated with long term low level occupational exposure to CS2 were reinvestigated four years after the initial study in the same group of workers. The second study concerned 44 exposed and 31 matched control workers. For both studies a personal cumulative exposure Ec was calculated based on function specific exposure levels and the occupational histories, which were carefully re-established. The exposed workers' average Ec was 192 and 213 ppm-years (first and second study respectively). Where possible the values of both data sets were used in a final combined analysis. Effects were found on the motor nerve conduction velocity of the fast (-0.9 m/s) and slow (-1.0 m/s) fibres of the peroneal nerve, the sensory nerve conduction velocity in the hand and arm segment of the median (-2.1 m/s) and ulnar (-1.3 m/s) nerves, and in the sural nerve (-1.3 m/s). An increased refractory period was found in the sural nerve (+ 0.2 ms, + 11%), but not in the peroneal nerve. For the autonomic nervous system an effect was found on the heart frequency response to isometric muscle contraction (-4.7 beats/min, -26%) and maximal forced respiration (-3.2 beats/min, -16%). This study shows the importance of a detailed evaluation of past exposure data. The reinvestigation enabled a more precise estimation of the effects of CS2, which is particularly desirable at around threshold exposure.
Harabuchi I, Kishi R, Ikeda T
… +2 more, Kiyosawa H, Miyake H
Br J Ind Med
· 1993 Mar · PMID 8457497
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To investigate circadian variations in the acute toxicity of toluene, rats were exposed to it (2000 ppm or 4000 ppm) both in the dark (the animals' active phase) and the light (the inactive phase) for 4 hours. The perfor...To investigate circadian variations in the acute toxicity of toluene, rats were exposed to it (2000 ppm or 4000 ppm) both in the dark (the animals' active phase) and the light (the inactive phase) for 4 hours. The performance decrements of rats were greater in the light phase than in the dark phase in all time zones of exposure to toluene. In the dark phase, the performance recovered almost to that pre-exposure, whereas a significant delay of recovery was noted in the light phase. The differences in the number of lever presses between exposure to 2000 ppm toluene and control (air) exposure were also greater in the light phase than in the dark phase. Significant differences according to the time of exposure were also found in toluene concentrations in blood and the brain. Both blood and brain concentrations in the light phase were higher than those in the dark phase at four hours after exposure to 2000 ppm toluene or at two hours after exposure to 4000 ppm toluene. These results suggest that there was a significant difference in circadian susceptibility after exposure to toluene, which might be caused by circadian differences in the pharmacokinetics of toluene in the light and dark phases.
Br J Ind Med
· 1993 Mar · PMID 8457496
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A high prevalence of sleep apnoea was found in a group of men occupationally exposed to organic solvents. Workers with long term exposure to organic solvents often report symptoms such as fatigue, forgetfulness, and conc...A high prevalence of sleep apnoea was found in a group of men occupationally exposed to organic solvents. Workers with long term exposure to organic solvents often report symptoms such as fatigue, forgetfulness, and concentration difficulties. These symptoms are strikingly similar to those reported by patients with obstructive sleep apnoea syndrome (OSAS). This is a frequently diagnosed disorder characterised by disturbed sleep causing psychic or somatic complications and daytime sleepiness. A study was undertaken to evaluate whether people with long term occupational exposure to organic solvents have a higher prevalence of sleep apnoea than the general population. Patients exposed to solvents (66 men) were invited to participate in a screening for sleep apnoea. A static charge sensitive bed was used for the monitoring of respiration movements and pulse oximetry during one night. A classical sleep apnoea was diagnosed if periodic respiration movement exceeded 45% of estimated sleep time and the oxygen desaturation index exceeded 6. The prevalence of sleep apnoea among the men exposed to solvents was compared with the prevalence in the general population (1.4%). The prevalence among the participating exposed men was 19.7% which gave a conservative relative risk estimate of 14.1 (95% confidence interval (95% CI) 7.5-24.2). The results indicate that exposure to organic solvents causes sleep apnoea. An alternative possibility is that people with sleep apnoea are misdiagnosed as cases of solvent induced toxic encephalopathy. The interpretation has importance for the caring of the patient.
Br J Ind Med
· 1993 Mar · PMID 8457495
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The International Labour Organisation (ILO) classification of radiographs of pneumoconioses was developed to limit variation in classification of parenchymal abnormalities. In this study the manner in which chest radiogr...The International Labour Organisation (ILO) classification of radiographs of pneumoconioses was developed to limit variation in classification of parenchymal abnormalities. In this study the manner in which chest radiographs were interpreted in 134 investigations reported in four peer reviewed journals during the five year period 1985-90 was examined. The approach for applying the ILO system was poorly described in most studies. For example, of 86 investigations using more than one reader, 66.3% described the method of reconciliation, but methods were not consistent among investigations. Our results indicate a number of potential problems in application of the ILO system, and gaps in existing recommendations that should be considered.
Br J Ind Med
· 1993 Mar · PMID 8457494
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OBJECTIVE: To explore associations between exposure to cement dust and cause specific mortality and tumour morbidity, especially gastrointestinal tumours. DESIGN: A retrospective cohort study. SUBJECTS AND SETTING: 2400...OBJECTIVE: To explore associations between exposure to cement dust and cause specific mortality and tumour morbidity, especially gastrointestinal tumours. DESIGN: A retrospective cohort study. SUBJECTS AND SETTING: 2400 men, employed for at least 12 months in two Swedish cement factories. MAIN OUTCOME MEASURES: Cause specific morality from death certificates (1952-86). Cancer morbidity from tumour registry information (1958-86). Standardised mortality rates (SMRs; national reference rates) and standardised morbidity incidence rates (SIRs; regional reference rates) were calculated. RESULTS: An increased risk of colorectal cancer was found > or = 15 years since the start of employment (SIR 1.6, 95% confidence interval (95% CI) 1.1-2.3), mainly due to an increased risk for tumours in the right part of the colon (SIR 2.7, 95% CI 1.4-4.8), but not in the left part (SIR 1.0, 95% CI 0.3-2.5). There was a numerical increase of rectal cancer (SIR 1.5, 95% CI 0.8-2.5). Exposure (duration of blue collar employment)-response relations were found for right sided colon cancer. After > or = 25 years of cement work, the risk was fourfold (SIR 4.3, 95% CI 1.7-8.9). There was no excess of stomach cancer or respiratory cancer. Neither total mortality nor cause specific mortality were significantly increased. CONCLUSIONS: Diverging risk patterns for tumours with different localisations within the large bowel were found in the morbidity study. Long term exposure to cement dust was a risk factor for right sided colon cancer. The mortality study did not show this risk.
Senanayake N, Gurunathan G, Hart TB
… +5 more, Amerasinghe P, Babapulle M, Ellapola SB, Udupihille M, Basanayake V
Br J Ind Med
· 1993 Mar · PMID 8457493
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Pulmonary function tests (FVC, FEV1, FEV1/FVC%, TLCO, single breath CO diffusion), chest x ray film, renal function (serum creatinine and blood urea nitrogen), liver function (serum alanine aminotransferase, aspartate tr...Pulmonary function tests (FVC, FEV1, FEV1/FVC%, TLCO, single breath CO diffusion), chest x ray film, renal function (serum creatinine and blood urea nitrogen), liver function (serum alanine aminotransferase, aspartate transferase, and alkaline phosphatase, bilirubin, total protein, and albumin), a haematological screen (haemoglobin and packed cell volume), and a general clinical examination were performed on 85 paraquat spraymen (mean spraying time 12 years) and on two control groups (76 factory workers and 79 general workers) frequency matched for age and years of occupational service. All the subjects were men. There were no clinically important differences in any of the measurements made between the study group and the two control groups. In particular the results of the lung function tests, appropriate for paraquat toxicity of the study group, were similar to those of the control groups. The same was true of blood tests for liver and kidney function. The incidence of skin damage, nose bleeds, and nail damage in the study group was slightly higher than in the control groups but lower than the incidence reported for paraquat workers in previous studies. The results of this study confirmed that long term spraying of paraquat, at the concentrations used, produced no adverse health effects, in particular no lung damage, attributable to the occupational use of the herbicide.
Br J Ind Med
· 1993 Mar · PMID 8457492
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To evaluate the effects of working with modern insulation materials (rock and glass wool), the members of the Copenhagen Union of Insulation Workers were invited to participate in a study based on a health examination th...To evaluate the effects of working with modern insulation materials (rock and glass wool), the members of the Copenhagen Union of Insulation Workers were invited to participate in a study based on a health examination that included lung function tests. Three hundred and forty men (74%) agreed to participate, and 166 bus drivers served as the control group. Age distribution, height, and smoking habits were similar in the two groups. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were used as tests for lung function. There were no differences in FVC between the study and control groups, but the insulation workers had significantly lower values of FEV1 (mean 2.51) compared with the controls (mean 3.4 1), independent of smoking habits. Six years before the present study, 114 of the insulation workers participated in a similar study, and eight years after the initial study, the lung function of 59 of the bus drivers was tested. The decline in FVC in insulation workers who smoked was significantly higher (7.7 cl/year) than in bus drivers who smoked (3.1 cl/year); the decline in FEV1 was significantly higher in insulation workers independent of smoking habits (17.0 cl/year v 2.9 cl/year). Self assessed former exposure to asbestos was not associated with lung function in insulation workers. The study concludes that working with modern insulation materials is associated with increased risk of developing obstructive lung disease.
Br J Ind Med
· 1993 Mar · PMID 8457491
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For the years 1987-1990 160 individual samples of manual metal arc stainless steel (MMA/SS) welding fumes from the breathing zone of welders in four industrial plants were collected. Concentrations of soluble and insolub...For the years 1987-1990 160 individual samples of manual metal arc stainless steel (MMA/SS) welding fumes from the breathing zone of welders in four industrial plants were collected. Concentrations of soluble and insoluble chromium (Cr) III and Cr VI compounds as well as of some other welding fume elements (Fe, Mn, Ni, F) were determined. Concentration of welding fumes in the breathing zone ranged from 0.2 to 23.4 mg/m3. Total Cr amounted to 0.005-0.991 mg/m3 (including 0.005-0.842 mg/m3 Cr VI). Total Cr content of fumes varied from 0.1 to 7.4%. The distribution of particular Cr compounds was: 52.6% soluble Cr (including 50.7% Cr VI), 65.5% total Cr VI, and 11.4% insoluble Cr VI. The results obtained indicate that MMA/SS welding is a process that could be highly hazardous to human health. Evaluation of occupational exposure has shown that MMA/SS welders may exceed the admissible concentrations of soluble and insoluble Cr VI forms as well as of Mn and Ni. In the plants investigated the sum of the ratios of concentrations of particular welding fumes in the breathing zone of welders exceeded corresponding maximum allowable concentration values by 24 times (including 17 times for total Cr VI). Due to the variety and changeability of particular parameters occurring in the working environment, the composition of MMA/SS welding fumes (in the welder's breathing zone) is so variable that it is not possible to assess the exposure by means of one universal exposure indicator (maximum additive hygienic limit value). The evaluation should be based on the results of measurements of concentrations of particular elements in welding fumes.
Moulin JJ, Wild P, Haguenoer JM
… +7 more, Faucon D, De Gaudemaris R, Mur JM, Mereau M, Gary Y, Toamain JP, Birembaut Y
Br J Ind Med
· 1993 Mar · PMID 8457490
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A mortality study was carried out in conjunction with the European mortality study among welders coordinated by the International Agency for Research on Cancer (IARC). The study was aimed at assessing risks for lung canc...A mortality study was carried out in conjunction with the European mortality study among welders coordinated by the International Agency for Research on Cancer (IARC). The study was aimed at assessing risks for lung cancer in relation to exposure to asbestos, welding fumes containing chromium and nickel, and tobacco smoke. The study included a cohort of 2721 welders and an internal comparison group of 6683 manual workers employed in 13 factories in France. The mortality of the two cohorts was studied from 1975 to 1988 by the historical prospective method. Job histories of welders were traced including welding processes used, metals welded, and proportion of worktime spent in welding. Data on smoking habits were collected from medical records. The observed number of deaths were compared with those expected (standardised mortality ratio (SMR)) based on national rates with adjustments for age, sex, and calendar time. The smoking habits of 87% of the whole study population were known. The distribution of welders and controls according to smoking was not statistically different. The overall mortality was slightly higher for welders (SMR = 1.02, 95% confidence interval (95% CI) 0.89-1.18) than for controls (SMR = 0.91, 95% CI 0.84-0.99). For lung cancer, the SMR was 1.24 (95% CI 0.75-1.94) for welders, whereas the corresponding value was lower for controls (SMR = 0.94, 95% CI 0.68-1.26). The SMR for lung cancer was 1.59 among non-shipyard mild steel welders (95% CI 0.73-3.02). This contrasted with the results for all stainless steel welders (SMR = 0.92, 95% CI 0.19-2.69), and for stainless steel welders predominantly exposed to chromium VI (SMR = 1.03, 95% CI 0.12-3.71). Moreover, SMRs for lung cancer for mild steel welders tended to increase with duration of exposure and time since first exposure, leading to significant excesses for duration > or = 20 years and latency > or = 20 years. Such a pattern was not found for stainless steel welders.
Ogawa Y, Hirata M, Okayama A
… +2 more, Ichikawa YE, Goto S
Br J Ind Med
· 1993 Mar · PMID 8457489
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The latency of the soleus muscle potential, evoked by a tap of the Achilles tendon, was used in the mass assessment of healthy male workers exposed to lead. Three groups were studied: a control, a low exposure, and a hig...The latency of the soleus muscle potential, evoked by a tap of the Achilles tendon, was used in the mass assessment of healthy male workers exposed to lead. Three groups were studied: a control, a low exposure, and a high exposure group. Mean blood lead concentrations were 9.3, 19.2, and 53.1 micrograms/100 ml respectively. Latencies were adjusted for age and height and then compared among the three groups. The mean corrected latency of the high exposure group showed a 4% increase compared with the other two groups (p < 0.01). The latencies of the other two groups showed no between group differences. These results were consistent with previous neurophysiological studies done by many researchers on workers exposed to lead. They suggested that nerve conduction velocities decreased from 3 to 13% among workers whose mean blood lead concentrations were more than 30 micrograms/100 ml. The method was simple, time conserving, non-invasive, and non-aversive, and provided a quantitative measure of the nerve conduction velocities of peripheral nerves. Thus it may be useful for early detection of occupationally related impairment of peripheral nerves.