Showing papers in "Occupational and Environmental Medicine in 1991"
TL;DR: The results imply that the true frequency of acute occupational respiratory disease in the United Kingdom may have been three times greater than that reported.
Abstract: A voluntary scheme for the surveillance of work related and occupational respiratory disease (SWORD) was established in January 1989 with help from the British Thoracic Society and the Society of Occupational Medicine and support from the Health and Safety Executive. Three hundred and fifty four chest physicians representing 90% of the chest clinics in the United Kingdom and 361 occupational physicians submit reports regularly of newly diagnosed cases of work related respiratory illness with information on age, sex, residence, occupation, and suspected causal agent. In 1989 2101 cases were notified, of which frequent diagnoses were asthma (26%), mesothelioma (16%), pneumoconiosis (15%), benign pleural disease (11%), and allergic alveolitis (6%). Incidence rates calculated against denominators from the Labour Force Survey showed very large differences between occupational groups, especially for asthma and asbestos related diseases. Substantial regional variation in the incidence of asthma was not explained by the geographical distribution of high risk industries and was probably due to differing levels of ascertainment. The results imply that the true frequency of acute occupational respiratory disease in the United Kingdom may have been three times greater than that reported.
289 citations
TL;DR: Regulators should proceed with caution before making further changes to the exposure limit for benzene, which involves multiple mechanisms including synergism between arylating and glutathione-depleting reactive metabolites and oxygen radicals.
Abstract: Benzene, a common industrial chemical and a component of gasoline, is radiomimetic and exposure may lead progressively to aplastic anaemia, leukaemia, and multiple myeloma. Although benzene has been shown to cause many types of genetic damage, it has consistently been classified as a non-mutagen in the Ames test, possibly because of the inadequacy of the S9 microsomal activation system. The metabolism of benzene is complex, yielding glucuronide and sulphate conjugates of phenol, quinol, and catechol, L-phenylmercapturic acid, and muconaldehyde and trans, trans-muconic acid by ring scission. Quinol is oxidised to p-benzoquinone, which binds to vital cellular components or undergoes redox cycling to generate oxygen radicals; muconaldehyde, like p-benzoquinone, is toxic through depletion of intracellular glutathione. Exposure to benzene may also induce the microsomal mixed function oxidase, cytochrome P450 IIE1, which is probably responsible for the oxygenation of benzene, but also has a propensity to generate oxygen radicals. The radiomimetic nature of benzene and its ability to induce different sites of neoplasia indicate that formation of oxygen radicals is a major cause of benzene toxicity, which involves multiple mechanisms including synergism between arylating and glutathione-depleting reactive metabolites and oxygen radicals. The occupational exposure limit in the United Kingdom (MEL) and the United States (PEL) was 10 ppm based on the association of benzene exposure with aplastic anaemia, but recently was lowered to 5 ppm and 1 ppm respectively, reflecting a concern for the risk of neoplasia. The American Conference of Governmental Industrial Hygienists (ACGIH) has even more recently recommended that, as benzene is considered an A1 carcinogen, the threshold limit value (TLV) should be decreased to 0.1 ppm. Only one study in man, based on nine cases of benzene associated fatal neoplasia, has been considered suitable for risk assessment. Recent re-evaluation of these data indicated that past assessments may have overestimated the risk, and different authors have considered that lifetime exposure to benzene at 1 ppm would result in an excess of leukaemia deaths of 9.5 to 1.0 per 1000. Although in this study, deaths at low levels of benzene exposure were associated with multiple myeloma and a long latency period, instead of leukaemia, which might justify further lowering of the exposure limit, the risk assessment model has been found to be non-significant for response at low levels of exposure. The paucity of data for man, the complexity of the metabolic activation of benzene, the interactive and synergistic mechanisms of benzene toxicity and carcinogenicity, the different disease endpoints (aplastic anaemia, leukaemia, and multiple myeloma), and different individual susceptibilities, all indicate that in such a complex scenario, regulators should proceed with caution before making further changes to the exposure limit for this chemical.
175 citations
TL;DR: It was concluded that symptoms included in SBS are common in the general population, and of multifactorial origin related to both personal, occupational, and residential factors, and certain environmental exposures such as maternal smoking, the urban environment, VDU work, and volatile organic hydrocarbons from newly painted dwellings.
Abstract: Possible relations between prevalence of sick building syndrome (SBS) and environmental, occupational, and personal factors were studied in a random sample (0.1%) of the general population aged 20-65 in a three county region in middle Sweden. Childhood exposure to environmental tobacco smoke from smoking mothers and a childhood in urban areas was related to SBS symptoms. Current urban residency, fresh paint, and preschool children in the dwelling were also related to symptoms. Other residential factors such as age of building, type of building, degree of crowding, mechanical ventilation, or signs of moisture or mould growth were not related to symptoms. Other factors related to symptoms were history of atopy, allergy to nickel, proneness to infection, hyperreactivity, static electricity, work with video display units (VDU), work satisfaction, and climate of cooperation at work. Age, sex, marital state, education level, work stress, obesity, current or earlier smoking, regular physical exercise, or occupational exposure to chemicals did not correlate with symptoms. Women had a higher proportion of symptoms than men but these differences were not significant when adjusting for differences in allergy to nickel, hyperreactivity, and proneness to infection. Maternal smoking was related to a twofold increase of both atopy and allergy to nickel in the adult offspring. Eye symptoms were most common in administrative, managerial, and service work. Airway symptoms were most common in transport and communication work. Dermal symptoms were most common in professional and technical and related work. General symptoms were most common in service, health, hospital, and social work. The lowest prevalence of symptoms was found in agricultural, forestry, and sales work. Women and subjects allergic to nickel worked more often in occupations without exposure to chemicals, but no evidence was found for selection mechanisms causing sensitive persons to move from exposed to unexposed occupations. It was concluded that symptoms included in SBS are common in the general population, and of multifactorial origin related to both personal, occupational, and residential factors, and certain environmental exposures such as maternal smoking, the urban environment, VDU work, and volatile organic hydrocarbons from newly painted dwellings.
172 citations
TL;DR: Women employed in departments in which fabric cleaning and parachute repair operations were performed had more deaths than expected from MM and NHL, and a variety of exposures for causes of death not showing excesses in the overall cohort.
Abstract: A retrospective cohort study of 14,457 workers at an aircraft maintenance facility was undertaken to evaluate mortality associated with exposures in their workplace. The purpose was to determine whether working with solvents, particularly trichloroethylene, posed any excess risk of mortality. The study group consisted of all civilian employees who worked for at least one year at Hill Air Force Base, Utah, between 1 January 1952 and 31 December 1956. Work histories were obtained from records at the National Personnel Records Centre, St. Louis, Missouri, and the cohort was followed up for ascertainment of vital state until 31 December 1982. Observed deaths among white people were compared with the expected number of deaths, based on the Utah white population, and adjusted for age, sex, and calendar period. Significant deficits occurred for mortality from all causes (SMR 92, 95% confidence interval (95% CI) 90-95), all malignant neoplasms (SMR 90, 95% CI 83-97), ischaemic heart disease (SMR 93, 95% CI 88-98), non-malignant respiratory disease (SMR 87, 95% CI 76-98), and accidents (SMR 61, 95% CI 52-70). Mortality was raised for multiple myeloma (MM) in white women (SMR 236, 95% CI 87-514), non-Hodgkin's lymphoma (NHL) in white women (SMR 212, 95% CI 102-390), and cancer of the biliary passages and liver in white men dying after 1980 (SMR 358, 95% CI 116-836). Detailed analysis of the 6929 employees occupationally exposed to trichloroethylene, the most widely used solvent at the base during the 1950s and 1960s, did not show any significant or persuasive association between several measures of exposure to trichloroethylene and any excess of cancer. Women employed in departments in which fabric cleaning and parachute repair operations were performed had more deaths than expected from MM and NHL. The inconsistent mortality patterns by sex, multiple and overlapping exposures, and small numbers made it difficult to ascribe these excesses to any particular substance. Hypothesis generating results are presented by a variety of exposures for causes of death not showing excesses in the overall cohort.
160 citations
TL;DR: In this population of men employed in the manufacture of asbestos cement products in 1969, excess risk of lung cancer was restricted to workers with x ray film evidence of asbestosis, consistent with the view that asbestos is a lung carcinogen because of its fibrogenicity.
Abstract: A prospective mortality study of 839 men employed in the manufacture of asbestos cement products in 1969 examined lung cancer risk in relation to lung fibrosis seen on chest x ray film, controlling for age, smoking, and exposure to asbestos. Twenty or more years after hire, no excess of lung cancer was found among workers without radiographically detectable lung fibrosis, even among long term workers (greater than or equal to 21.5 years); nor was there a trend in risk by level of cumulative exposure to asbestos among such workers. By contrast, employees with small opacities (greater than or equal to 1/0; ILO classification) experienced a significantly raised risk of lung cancer (nine observed deaths v 2.1 expected), even though their exposures to asbestos were similar to the exposures of long term workers without opacities. In this population, excess risk of lung cancer was restricted to workers with x ray film evidence of asbestosis, a finding consistent with the view that asbestos is a lung carcinogen because of its fibrogenicity.
143 citations
TL;DR: The results suggest the possibility that leucocytes, or platelets, or both, may induce haemolysis in the presence of lead, and the lowered concentration of glutathione and decreased activity of SOD, catalase, and glutathion peroxidase in erythrocytes from workers exposed to lead may play a part in the increased membrane lipid peroxidation.
Abstract: Lipoperoxide concentration in erythrocytes from workers occupationally exposed to lead (mean blood lead concentration 57.1 (SD 17.6) micrograms/dl) was significantly higher than that in controls. It was not different in plasma from the two groups. The activity of superoxide dismutase (SOD) and catalase in erythrocytes from workers exposed to lead was significantly lower than that of control subjects. The effect of lead was also seen in the glutathione concentration of erythrocytes from lead exposed workers, which was reduced to 69% of that found in erythrocytes from control workers. The increase in methaemoglobin content of erythrocytes from workers exposed to lead was less than expected and not significantly different from that of controls. A positive correlation between lipoperoxide concentration in erythrocytes and lead concentration in blood and a negative correlation between glutathione concentration in erythrocytes and blood lead concentration were found. Incubation of erythrocytes for 24 hours at 37 degrees C in the presence of lead (100 micrograms/dl) produced no changes in glutathione and lipoperoxide concentrations, although there was inhibition of activity of SOD (14.3%), catalase (10.1%), and glutathione peroxidase (35.1%). A similar experiment with heparinised whole blood showed increased haemolysis with no changes in membrane lipid peroxidation of erythrocytes. It is postulated that the lowered concentration of glutathione and decreased activity of SOD, catalase, and glutathione peroxidase in erythrocytes from workers exposed to lead may play a part in the increased membrane lipid peroxidation. Furthermore, the results suggest the possibility that leucocytes, or platelets, or both, may induce haemolysis in the presence of lead.
133 citations
TL;DR: Body mass index and HbA1C concentration were significantly associated with objective job strain independent of confounders and no significant association was found between coronary risk factors and subjective job strain.
Abstract: As part of the World Health Organisation initiated MONICA project, 2000 men and women aged 30, 40, 50, and 60 from the general population were invited to undergo a medical examination with special emphasis on cardiovascular disease. A total of 1504 (75%) participated, 1209 of whom were employed. The participants answered a questionnaire on working, social, and health conditions and underwent clinical examinations that included the measurement of blood pressure and serum cholesterol, triglyceride, high density lipoprotein, fibrinogen, and glycated haemoglobin (HbA1C) concentrations. Using the demand-control model for measuring job strain suggested by Karasek, the employed people were classified according to those who had suffered job strain and those who had not in two different ways. The subjective classification was based on the participants' statements regarding demand and control in their jobs whereas the objective classification was based on job title and mode of payment. More women than men were classified as having high strain jobs. After adjusting for age and sex no significant association was found between coronary risk factors and subjective job strain. A tendency for an association between fibrinogen and job strain was found. Body mass index and HbA1C concentration were significantly associated with objective job strain independent of confounders.
130 citations
TL;DR: The results indicate an increase in the rate of spontaneous abortions with an increasing concentration of mercury in the fathers' urine before pregnancy, which could be of practical importance.
Abstract: The potential reproductive toxicity of mercury vapour was investigated by comparing the rate of spontaneous abortions among the wives of 152 workers occupationally exposed to mercury vapour with the rate among the wives of 374 controls in the same plant. The results indicate an increase in the rate of spontaneous abortions with an increasing concentration of mercury in the fathers' urine before pregnancy. At concentrations above 50 micrograms/l the risk of spontaneous abortion doubles (odds ratio (OR) = 2.26; 95% confidence interval (95% CI) = 0.99-5.23). Special care was taken to avoid bias in reporting abortions and known risk factors of spontaneous abortions do not seem to explain the results. Several biological mechanisms might account for them including, in particular, direct action of mercury on the paternal reproductive system and indirect toxicity to the mother or embryo through transport of mercury from the father. These indications could be of practical importance and should therefore be further documented.
109 citations
TL;DR: The patterns of lung cancer mortality in these results suggest that the risk of Lung cancer is higher for stainless steel than mild steel welders the different level of risk for these two categories of welding exposure cannot be quantified with precision.
Abstract: A multicentre cohort of 11,092 male welders from 135 companies located in nine European countries has been assembled with the aim of investigating the relation of potential cancer risk, lung cancer in particular, with occupational exposure. The observation period and the criteria for inclusion of welders varied from country to country. Follow up was successful for 96.9% of the cohort and observed numbers of deaths (and for some countries incident cancer cases) were compared with expected numbers calculated from national reference rates. Mortality and cancer incidence ratios were analysed by cause category, time since first exposure, duration of employment, and estimated cumulative dose to total fumes, chromium (Cr), Cr VI, and nickel (Ni). Overall a statistically significant excess was reported for mortality from lung cancer (116 observed v 86.81 expected deaths, SMR = 134). When analysed by type of welding an increasing pattern with time since first exposure was present for both mild steel and stainless steel welders, which was more noticeable for the subcohort of predominantly stainless steel welders. No clear relation was apparent between mortality from lung cancer and duration of exposure to or estimated cumulative dose of Ni or Cr. Whereas the patterns of lung cancer mortality in these results suggest that the risk of lung cancer is higher for stainless steel than mild steel welders the different level of risk for these two categories of welding exposure cannot be quantified with precision. The report of five deaths from pleural mesothelioma unrelated to the type of welding draws attention to the risk of exposure to asbestos in welding activities.
108 citations
TL;DR: It was apparent that the physiological characteristics of vibration sensation at low and high frequencies differed significantly, suggesting that two representative frequencies can be used when evaluation the neurological effects of occupational exposures to vibration by means of vibration sense thresholds.
Abstract: The effects of various conditions, including temporary threshold shifts (TTS) induced by exposure to vibration on vibration sense thresholds, have been investigated. The vibration sense thresholds of five subjects were measured on the middle fingertip of the left hand. A contactor with a diameter of 7 mm was surrounded by three alternative plates with holes of different sizes. The contact force was controlled at either 1 N, 2 N, or 3 N. For the TTS test, the left hand was exposed to vibration at 20 ms-2 rms for five minutes. The frequencies of both the exposure to vibration and the vibration threshold test were in the range 16 Hz to 500 Hz. Using a surround around the contactor greatly reduced the vibration sense threshold at 16 Hz and 31.5 Hz but increased the threshold at 125 Hz, 250 Hz, and 500 Hz. An effect of contact force was seen only at the higher frequencies; larger contact forces led to lower thresholds at 125 Hz, 250 Hz, and 500 Hz. As temperature of the finger skin decreased, the vibration thresholds increased, with the changes at higher frequencies greater than those at lower frequencies. The TTS at 16 Hz and 31.5 Hz measured 0.5 minutes after exposure to vibration (TTS0.5) were highest after exposures to vibration at lower frequencies. The TTS0.5 at 63 Hz was similar after exposure to all frequencies. The TTS0.5 values at 125 Hz, 250 Hz, and 500 Hz were highest after exposures to vibration at 125 Hz and 250 Hz. It was apparent that the physiological characteristics of vibration sensation at low and high frequencies differed significantly. These findings suggest that two representative frequencies can be used when evaluation the neurological effects of occupational exposures to vibration by means of vibration sense thresholds.
106 citations
TL;DR: A positive association existed between silicosis of the hilar glands and lung cancer and the combined effect of dust and tobacco smoking was better fitted by the multiplicative model than the additive model, suggesting that the two exposures act synergistically.
Abstract: The effects of exposure to gold mining dust with a high concentration of free silica and tobacco smoking on mortality from lung cancer was assessed in a sample of 2209 white South African gold miners who started mining exposure during 1936-43, and were selected for a study of respiratory disorders in 1968-71 when they were aged 45-54. The mortality follow up was from 1968-71 to 30 December 1986. The relative risk for the effect of dust cumulated to the start of the follow up period was estimated as 1.023 (95% confidence interval (CI) 1.005-1.042) for a unit of 1000 particle-years. The combined effect of dust and tobacco smoking was better fitted by the multiplicative model than the additive model, suggesting that the two exposures act synergistically. No association between lung cancer and silicosis of the parenchyma or pleura was found, but a positive association existed between silicosis of the hilar glands and lung cancer.
TL;DR: Measurements of pyrethroid concentrations in the air of the breathing zone, in skin pads, and in urine samples showed that dermal contamination is the main route of exposure to pyrethroids in cotton growers.
Abstract: A cross sectional survey on the prevalence of acute pyrethroid poisoning in cotton farmers was conducted in 1987 and 1988. A total of 3113 pyrethroid spraymen (2230 men (71.6%) and 883 women (28.4%] were interviewed after spraying and followed up for 72 hours. Adverse effects of pyrethroid exposure were found in 834 of them (26.8%) manifested as abnormal facial sensations, dizziness, headache, fatigue, nausea, or loss of appetite. Only 10 subjects, who developed significant systemic symptoms and had signs of listlessness or muscular fasciculation, were diagnosed as having mild occupational acute pyrethroid poisoning with a prevalence of 0.31% in subjects exposed to pure pyrethroids and 0.38% in subjects exposed to pyrethroid organophosphate mixtures. Measurements of pyrethroid concentrations in the air of the breathing zone, in skin pads, and in urine samples showed that dermal contamination is the main route of exposure to pyrethroids in cotton growers. Preventive measures are recommended.
TL;DR: It is concluded that alpha-amylase powder is a potent occupational sensitiser and Precautions should be taken when handling this allergenic enzyme.
Abstract: alpha-Amylase is a starch cleaving enzyme often used in the baking industry as a flour additive. It is usually of fungal origin, produced by Aspergillus oryzae. One previous report has shown IgE antibodies and positive skin prick test against alpha-amylase in asthmatic bakers. This paper describes four alpha-amylase sensitised index cases with occupational asthma or rhinitis and the results of a cross sectional study of 20 workers from the same factory who were also exposed to alpha-amylase powder. Air sampling detected airborne alpha-amylase at a concentration of 0.03 mg/m3. Significantly more work related symptoms such as rhinitis and dermatitis were found among the alpha-amylase exposed workers compared with referents. A skin prick test to alpha-amylase was positive in 30% (6/20) of the exposed workers. Most of the persons showing a positive skin prick test had work related symptoms and were also skin prick test positive to common allergens. Nasal challenge tests with amylase were performed in selected cases and validated three cases of alpha-amylase induced rhinitis. Two non-symptomatic workers had precipitins to alpha-amylase. Specific IgG antibodies were shown by two further serological techniques. The nature and relevance of these antibodies are currently being studied. It is concluded that alpha-amylase powder is a potent occupational sensitiser. Precautions should be taken when handling this allergenic enzyme.
TL;DR: It appears that the use of a respiratory protection mask will not protect efficiently against exposure to BE vapours, and a tendency towards increased percutaneous absorption rate was seen in the raised temperature and humidity condition.
Abstract: Four male volunteers were exposed at rest for two periods of two hours, separated by a one hour exposure free interval, to 50 ppm 2-butoxyethanol (BE) vapour generated in an exposure chamber. During the first two hour period the men were exposed by mouth only via a respiratory valve connected by tubes to the exposure chamber. During the second exposure period the men were exposed by skin only while sitting inside the exposure chamber, naked except for shorts, and wearing a respiratory protection mask supplied with compressed air. Capillary blood samples were collected at regular intervals and analysed for BE by a gas chromatographic method. Two experiments separated by at least two weeks were carried out with each volunteer, one at "normal" (23 degrees C, 29% relative humidity) and one at raised (33 degrees C, 71% relative humidity) air temperature and humidity in the chamber. The average concentration in blood and the calculated rate of uptake of BE were about three to four times higher during dermal exposure than during inhalation exposure. These experiments suggest that dermal uptake of BE accounts for about 75% (45-85% in individual experiments) of the total uptake during whole body exposure to BE vapour. Thus it appears that the use of a respiratory protection mask will not protect efficiently against exposure to BE vapours. A tendency towards increased percutaneous absorption rate was seen in the raised temperature and humidity condition.
TL;DR: Three cases of malignant melanoma of the nasal mucosa in persons occupationally exposed to formaldehyde for a long time are presented and the occurrence of such a rare tumour in patients with significant exposure to a known carcinogen warrants further investigation.
Abstract: Formaldehyde is a well known nasal carcinogen in rodents, but so far there has been no convincing evidence that workers occupationally exposed to formaldehyde have an increased risk of nasal cancer. In this study three cases of malignant melanoma of the nasal mucosa in persons occupationally exposed to formaldehyde for a long time are presented. The occurrence of such a rare tumour in patients with significant exposure to a known carcinogen warrants further investigation.
TL;DR: Moderate exposure to lead was associated in dose related fashion with small but measurable changes in male endocrine functions that reflected both primary and secondary effects of lead on the testes and the hypothalamo pituitary testicular axis.
Abstract: Evidence for the effect of occupational exposure to lead on the male endocrine system is conflicting. This study evaluated the primary (testicular) and secondary (hypothalamo pituitary testicular) effects of exposure to lead in 122 current lead workers and 49 non-exposed workers. The mean current blood lead concentration was 35.2 (range 9.6-77.4) micrograms/dl in the exposed workers, and 8.3 (range 2.6-14.8) micrograms/dl in the non-exposed workers. Concentrations of plasma luteinising hormone (LH) and follicle stimulating hormone (FSH) were both significantly higher in the exposed workers, but testosterone (T) was not significantly different between the two groups. In older exposed workers, however (greater than or equal to 40 years), plasma T concentrations were significantly lower, but LH and FSH concentrations were not significantly different. Compared with non-exposed workers, those exposed for less than 10 years had significantly raised LH and FSH and normal T concentrations whereas those exposed for 10 or more years had significantly lower T, and normal LH and FSH concentrations. The concentrations of LH and FSH showed a moderate increase in relation to blood lead concentrations in the range of 10 micrograms/dl to 40 micrograms/dl and thereafter reached a plateau or declined. No apparent trend for plasma T concentrations occurred. No significant difference in prolactin (PRL) concentration was noted. It is concluded that moderate exposure to lead was associated in dose related fashion with small but measurable changes in male endocrine functions that reflected both primary and secondary effects of lead on the testes and the hypothalamo pituitary testicular axis.
TL;DR: The risk among earlier entrants affected men with two or more years of employment and was highest among those working for 10 years or longer (SMRA 225); the relative risk was already raised 5-14 years after first employment; it was highest in the 25-40 year period, but was still raised 50 years afterFirst exposure.
Abstract: This report updates a 1981 study of mortality at three United Kingdom chromate producing factories, and pays special attention to workers engaged after major plant and process changes were completed during 1958-60. The study covers 2298 payroll workers in post on 1 January 1950 or entering employment up to 30 June 1976 and remaining at least one year, with mortality observed up to 31 December 1988. Expected numbers of deaths were calculated from national death rates adjusted for social class and area differences. At the two largest factories 1422 men starting work before the process changes showed a highly significant excess of deaths from lung cancer (observed deaths/adjusted expected deaths (obs/expA) 175/88.97, adjusted standardised mortality ratio (SMRA) 197). They also had a significant excess of deaths from nasal cancer (obs/expA 4/0.26, SMRA 1538); the four affected men all had over 20 years of employment. Six hundred and seventy seven men starting work after the completion of process changes showed no excess of lung cancer deaths (obs/expA 14/13.7, SMRA 102, 95% confidence interval (95% CI) 56-171), but the possibility of the risk persisting at a reduced level cannot be excluded. The risk among earlier entrants affected men with two or more years of employment and was highest among those working for 10 years or longer (SMRA 225). The relative risk was already raised 5-14 years after first employment; it was highest in the 25-40 year period, but was still raised 50 years after first exposure. The risk showed most clearly at young ages, with a SMRA of 355 for ages under 50 (obs/expA 21/5.91). The excess was greater among men in jobs with high exposure to chromates (obs/expA 151/61.73, SMRA 245) than among men in less exposed jobs (obs/expA 21/19.57, SMRA 107). Less evidence of a lung cancer excess was found among 199 men employed at a third small factory (obs/expA 12/9.91, SMRA 121). No risk was apparent in further groups of 214 salaried works staff (obs/expA 1/2.53), or 95 workers at an adjacent fertiliser plant (obs/expA 3/3.95). No significant excesses of deaths from cancers of other sites were found.
TL;DR: Dermal exposure, particularly on the legs, feet, and hands was appreciable and indicated that this was the main route of absorption as well as air concentration, dermal exposure concentration, and urinary content of pyrethroids by gas chromatography.
Abstract: To assess the exposure response relation of pyrethroids in spraymen, 50 adult male cotton growers were selected and divided into three groups, one group to spray pyrethroids for one day, two groups to spray for three days. Deltamethrin, fenvalerate, and a deltamethrin methamidophos mixture were sprayed by appropriate subgroups for five hours a day. Exposure levels were evaluated by measuring the air concentration, dermal exposure concentration, and urinary content of pyrethroids by gas chromatography. Air concentrations of deltamethrin at the breathing zone were 0.01-0.89 microgram/m3 in the deltamethrin exposed group. For fenvalerate, air concentrations were 0.06-1.98 micrograms/m3. Dermal exposure, particularly on the legs, feet, and hands was appreciable and indicated that this was the main route of absorption. In those spraying for one day, urinary deltamethrin was not detectable by 12 hours after the beginning of exposure whereas fenvalerate was still detectable up to 24 hours after first exposure. Both pyrethroids could be detected two days after the end of three day spraying. Health effects were investigated by interview and physical examination. Twenty nine spraymen complained of abnormal facial sensations that developed mostly two to three hours from the start of pyrethroid spraying and that disappeared by 24 hours after exposure ceased. Some had dizziness, headache, and nausea, but no subject was diagnosed as having acute pyrethroid poisoning. The symptoms showed no significant correlation with urinary pyrethroid excretion. Blood cholinesterase activity of spraymen using the pyrethroid methamidophos mixture did not change.
TL;DR: A 19 year follow up study was conducted to explore the association between occupations expected to be exposed to electromagnetic fields and the occurrence of leukaemia and brain tumours and the hypothesis that magnetic fields might play a part in the origin of cancer cannot be rejected.
Abstract: A 19 year follow up study was conducted to explore the association between occupations expected to be exposed to electromagnetic fields and the occurrence of leukaemia and brain tumours. Incidence of cancer between 1961-79 was calculated and the standardised morbidity ratio (SMR) with a 95% confidence interval (95% CI) was related to that of all Swedish working men. For all the selected "electrical occupations" the SMRs for total leukaemia and brain tumours were near unity. Increased risks were noted for all leukaemia among electrical/electronic engineers and technicians, (SMR 1.3; 95% CI 1.0-1.7) as well as in the sub-groups of telegraph/telephone (2.1; 1.1-3.6) and machine (2.6; 1.0-5.8) industries. Risk for chronic lymphoid leukaemia was increased in the same occupational category (1.7; 1.1-2.5) and in the sub-group of machine industry (4.8; 1.0-14.0), as well as for all linesmen (2.0; 1.0-3.5) and power linesmen (2.8; 1.1-5.7). Risk for acute myeloid leukaemia was increased among all miners (2.2; 1.0-4.1) and miners working in iron/ore mines (5.7; 2.1-12.4). Increased risk for all brain tumours (2.9; 1.2-5.9) and glioblastomas (3.4; 1.1-8.0) appeared among assemblers and repairmen in radio and TV industry. Raised risk for all brain tumours was seen for all welders (1.3; 1.0-1.7) and welders in iron/steel works (3.2; 1.0-7.4) and risk for glioblastomas was also increased for all welders (1.5; 1.1-2.1). No major changes in relative risk estimates were noted after the exclusion of persons who were over 65 at the time of diagnosis. Although a homogeneous pattern of increased risks of leukaemia or brain tumour was not noted, the hypothesis that magnetic fields might play a part in the origin of cancer cannot be rejected.
TL;DR: Regression analysis of data from the pituitary glands and occipital cortices of dental staff indicated the accumulation of Se at a rough stoichiometric ratio of 1:1 with Hg; it is assumed that this corresponds to biologically available Se.
Abstract: Mercury (Hg) and selenium (Se) concentrations were determined by radiochemical neutron activation analysis in samples from the pituitary glands, occipital cortices, renal cortices, abdominal muscles, and thyroid glands of cadavers. Samples were retrieved from dental staff occupationally exposed to Hg and from the general population. Increased concentrations of both Hg and Se in samples from dental staff showed that Se accumulated together with Hg. Regression analysis of data from the pituitary glands and occipital cortices of dental staff indicated the accumulation of Se at a rough stoichiometric ratio of 1:1 with Hg. The same stoichiometric ratio between the elements was seen in the renal cortices from the general population. The regression analysis showed that a substantial fraction of Se was not associated with Hg; it is assumed that this corresponds to biologically available Se. Concentrations of biologically available Se decreased with advancing age in the pituitary gland, but not in other organs, and varied appreciably between organs.
TL;DR: It is concluded that the primary psychological profile of lead impairment is one of sensory motor slowing coupled with difficulties in remembering incidental information.
Abstract: In a short term prospective study 70 male lead workers performed a series of cognitive tasks on three occasions during an eight month period. Concurrently with the cognitive testing, the concentrations of blood lead, zinc protoporphyrin (ZPP) and urinary aminolaevulinic acid (ALA) were measured. Indicators of lead absorption were stable during the study and each subject was allocated to either a low (below 20 micrograms/dl), medium (21-40 micrograms/dl), or high (41-80 micrograms/dl) group on the basis of their average blood lead concentrations. Performance deficits tended to be restricted to the high lead group and, in general, neither practice nor continued exposure during the study altered the magnitude of these deficits. The main deficit was a slowing of sensory motor reaction time, which was seen most clearly when the cognitive demands of the task were low. In the cognitively simple five choice task, blood lead concentration correlated with impaired decision making, response execution, and "lapses in concentration." In the other cognitive tasks the high blood lead group tended also to be slower by a factor of about 1.08 but the dominance of cognitive over sensory motor demands attenuated the exposure-performance correlations. The high lead group also had difficulty in recalling nouns poorly related to the focus of an earlier semantic classification task. This difficulty increased over time and was one of the few findings that correlated with all measures of lead absorption. It is concluded that the primary psychological profile of lead impairment is one of sensory motor slowing coupled with difficulties in remembering incidental information.
TL;DR: Whereas there is evidence of short term effects on mental health and of increased use of primary health care, no long term effects have been studied and objective data on physical health are almost non-existent.
Abstract: The dramatic rise in unemployment in the 1970s and 1980s has led to an increase in research into the possible effects of unemployment on health. Studies of the effects of job loss are difficult to interpret because of the difficulty in ruling out selection effects--for example, the least fit may be more likely to be made redundant. The study of factory closures is appealing since all employees are made redundant and all the studies of factory closure recorded in the Index Medicus since 1980 are reviewed. None of the studies fulfil all the criteria for an ideal study, and most fail on several counts. The small sample sizes are often unavoidable, but the lack of awareness of possible selection effects often results in a biased control group of only those people who are economically active. Also, the short duration of follow up restricts the detection of possible long term effects on health. Thus the conclusions that can be drawn about the health effects of factory closures are limited. Whereas there is evidence of short term effects on mental health and of increased use of primary health care, no long term effects have been studied and objective data on physical health are almost non-existent.
TL;DR: The effect of industrial noise on the prevalence of hypertension was studied in a group of 1101 female workers in a textile mill in Beijing in 1985, suggesting that, for those susceptible to the effect, hypertension was manifested within the first five years of exposure.
Abstract: The effect of industrial noise on the prevalence of hypertension was studied in a group of 1101 female workers in a textile mill in Beijing in 1985. Essentially the entire group had worked in specific workshops in this mill for all their working lives and all had worked for at least five years. The noise levels within the plant were assessed and appear to have been constant since 1954 resulting in well defined noise exposures for these workers. A cross sectional design was used in which blood pressures were determined and questionnaires administered to the workers over a two month period. As well as demographic information, data were gathered on personal and family history of hypertension, current use of prescription drugs, alcohol, tobacco, and salt in the diet. Logistic regression indicated that exposure to noise is a significant determinant of prevalence of hypertension, but third in order of importance behind family history of hypertension and use of salt. Each of the predictor variables exerted an independent influence on risk of hypertension. Cumulative exposure to noise was not an important dose related variable suggesting that, for those susceptible to the effect, hypertension was manifested within the first five years of exposure.
TL;DR: In this paper, the authors used a cohort mortality study of 15,000 employees who held 150,000 jobs at an Air Force base from 1939 to 1982. But they did not consider the use of specific chemicals to the departments identified in the work histories.
Abstract: Methods are presented that were used for assessing exposures in a cohort mortality study of 15,000 employees who held 150,000 jobs at an Air Force base from 1939 to 1982. Standardisation of the word order and spelling of the job titles identified 43,000 unique job title organisation combinations. Walkthrough surveys were conducted, long term employees were interviewed, and available industrial hygiene data were collected to evaluate historic exposures. Because of difficulties linking air monitoring data and use of specific chemicals to the departments identified in the work histories, position descriptions were used to identify the tasks in each job. From knowledge of the tasks and the chemicals used in those tasks the presence or absence of 23 chemicals or groups of chemicals were designated for each job organisation combination. Also, estimates of levels of exposure were made for trichloroethylene and for mixed solvents, a category comprising several solvents including trichloroethylene, Stoddard solvent, carbon tetrachloride, JP4 gasoline, freon, alcohols, 1,1,1-trichloroethane, acetone, toluene, methyl ethyl ketone, methylene chloride, o-dichlorobenzene, perchloroethylene, chloroform, styrene, and xylene.
TL;DR: The events triggered by exposure to TDI in sensitised subjects included changes in lung function and systemic effects which lasted longer than bonchoconstriction and concerned suppressor/cytotoxic lymphocytes and eosinophils.
Abstract: Occupational asthma induced by toluene diisocyanate (TDI) shares several features with allergic asthma, but the mechanism of action of TDI is poorly understood. Ten sensitised subjects, previously shown to develop a dual or late asthmatic reaction after inhaling TDI were examined. In each subject, forced expiratory volume in one second (FEV1) was measured and venous blood was taken before, and 30 minutes and eight, 24, 48, and 72 hours after exposure to TDI (0.005-0.015 ppm for 10-30 minutes). Filtered air was used as a control. Differential leucocyte counts were determined and phenotypic analysis was performed by immunofluorescence on mononuclear cells using monoclonal antibodies (anti-CD3, anti-CD4, anti-CD8, and anti-HLA-DR). Five subjects developed a dual asthmatic reaction and five had a late reaction. Percentage of CD8 positive lymphocytes increased significantly eight hours after exposure to TDI (from 27 +/- 3 (SEM) % to 42.1 +/- 5%) in the subjects with an isolated late reaction. A delayed significant further increase in suppressor/cytotoxic T lymphocytes was seen in seven of the 10 subjects 48 hours after active exposure (from 27 +/- 2% to 42 +/- 4.8%), irrespective of the type of asthmatic reaction developed after exposure to TDI. Eosinophil percentage increased from 2.5% +/- 1.0 to 6.4% +/- 1.2 24 hours after exposure to TDI and the increase was sustained for up to 48 hours (4.7 +/- 1.1%). No significant variations of FEV1 or cell percentages were seen in the controls. In conclusion, the events triggered by exposure to TDI in sensitised subjects included changes in lung function and systemic effects which lasted longer than bonchoconstriction and concerned suppressor/cytotoxic lymphocytes and eosinophils. These results suggest that TDI induced late asthmatic reactions may be associated with an immunological response to TDI or to its products.
TL;DR: The data suggest that after a few days of cessation of occupational exposure to mercury vapour the HgU before and after administration of DMSA mainly reflects the amount of mercury stored in the kidney, which represents a mercury pool with a slow turnover.
Abstract: The spontaneous and chelator mediated excretion of mercury in urine was investigated in male subjects occupationally exposed to mercury vapour (alkaline battery and chloralkali plants) who did not exhibit any sign of kidney damage. The time course of the spontaneous elimination of mercury in urine was examined in seven workers (age 22-40) who had been removed from exposure to mercury vapour (average duration of exposure 4.4 years) because their urinary mercury concentrations repeatedly exceeded 100 micrograms/g creatinine. The post exposure observation period started 10 to 29 days after the date of removal and lasted about 300 days (slow HgU elimination phase). For each worker, the kinetics of the spontaneous HgU decline followed a first order process; the biological half life ranged from 69 to 109 days (mean 90 days). The increased urinary excretion of mercury after a single oral administration of 2 g meso-2,3-dimercaptosuccinic acid (DMSA) was investigated in 16 control workers (group A; age 23 to 49), in 11 workers removed from exposure for at least two years (group B; age 27 to 41), and in 16 workers currently exposed to mercury vapour (group C; age 21 to 58). In group C, the DMSA experiment was repeated twice (three weeks before and three weeks after a holiday) after measures had been taken to reduce the mercury emission. The urinary mercury excretion was significantly higher during the 24 hours after DMSA administration in all groups compared with that in the 24 hours before. The bulk (50-70%) of the DMSA stimulated mercury excretion appeared within the first eight hours. In each group, the amount of mercury (microgram Hg/24h) excreted after DMSA was significantly correlated with that before administration of DMSA. The groups whose exposure had ceased, however, exhibited much higher correlation for coefficients (r=0.97 for group B and 0.86 for group C after three weeks of holiday) than those currently exposed to mercury vapour (r-0.66 for group C before and 9.58 after reduction of exposure). The data suggest that after a few days of cessation of occupational exposure to mercury vapour the HgU before and after administration of DMSA mainly reflects the amount of mercury stored in the kidney, which represents a mercury pool with a slow turnover.
TL;DR: After applying a multivariate model to control the non-occupational factors (alcohol, medication, age, and hepatitis B viral infection), increase in gamma-glutamyl transferase (GGT) activity was found to be associated with severity of exposure to the mixture of solvents.
Abstract: The objective of this study was to determine biochemical alterations of liver function among paint manufacturers and sprayers associated with exposure to organic solvents. Two paint manufacturing factories and 22 various kinds of spray painting factories (16 car painting, two aircraft painting, three video terminal painting; and one trailer painting) were included. Air concentrations of organic solvents were collected by personal samplers and analysed by gas chromatography. A total of 180 workers were given a comprehensive physical examination, a questionnaire, a liver function test, and a test for hepatitis B surface antigen. The questionnaire contained questions regarding detailed personal medical history, intake of alcohol, and use of medicine. Mixtures of solvents were used throughout the factories, and xylene and toluene were the major components found in almost all air samples with average contents of 46% and 29% on a weight basis of 67 air samples. No strong hepatotoxic solvents were detected. Workers were classified according to the different exposure patterns and different air concentrations of breathing zones as: high (eight hour time weighted average (8 h TWA) hygienic effects of solvents 0.25-9.83, median 1.66), short term high (8 h TWA hygienic effects of solvents 0-3.38, median 0.12), and low (8 h TWA hygienic effects of solvents all below 0.38). After applying a multivariate model to control the non-occupational factors (alcohol, medication, age, and hepatitis B viral infection), increase in gamma-glutamyl transferase (GGT) activity was found to be associated with severity of exposure to the mixture of solvents. Because the possible effects on GGT activity of non-occupational factors were controlled for, it is concluded that increased GGT activity among exposed workers may be due to a higher exposure to the mixture of solvents.
TL;DR: EtOH may be a useful acute standard to compare the effects of various industrial solvents and support investigating an association between exposure to solvented and increased risk to safety in industry.
Abstract: A comparison of toluene and ethanol (EtOH) induced changes in central nervous system (CNS) function and symptoms were evaluated in two studies, and when possible the effects of toluene were expressed in EtOH equivalent units. The toluene concentrations were 0, 75, and 150 ppm, bracketing the American Conference of Governmental Industrial Hygienists threshold limit value (ACGIH TLV) of 100 ppm. The socially relevant EtOH doses were 0.00, 0.33, and 0.66 g EtOH/kg body weight, equivalent to two and four 3.5% 12 ounce beers. Forty two paid college students were used in each study. In the first study, subjects were exposed to toluene and an odour masking agent menthol (0.078 ppm) for seven hours over three days. In the second study EtOH or a placebo was administered at 1530 across three days also in the presence of menthol. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory), perception (pattern recognition), psychomotor skill (simple reaction time, continuous performance, symbol-digit, hand-eye coordination, finger tapping, and critical tracking), manual dexterity (one hole), mood (profile on mood scales (POMS), fatigue (fatigue checklist), and verbal ability were evaluated at 0800, 1200, and 1600. Voluntary symptoms and observations of sleep were collected daily. A 3 x 3 latin square design evaluated solvent effects simultaneously controlling for learning and dose sequence. An analysis of variance and test for trend were performed on am-pm differences reflecting an eight hour workday and on pm scores for each solvent, in which subjects were their own control Intersubject variation in absorbance was monitored in breath. A 5 to 10% decrement was considered meaningful if consistent with a linear trend at p less than 0.05. At 150 ppm toluene, losses in performance were 6.0% for digit span, 12.1% for pattern recognition (latency), 5% for pattern memory (number correct), 6.5% for one hole, and 3% for critical tracking. The number of headaches and eye irritation also increased in a dose-response manner. The greatest effect was found for an increasing number of observations of sleep. A range of 2 to 7% decrements suggest the ACGIH TLV of 100 ppm toluene may be a good estimate of the biological threshold supporting a re-evaluation of the TLV. At 0.66 g EtOH/kg body weight symptoms and performance decrements were 6.6% for digit span, 9.2% for pattern recognition, 4.0% for continuous performance, 7.9% for symbol-digit, 16.5% for finger tapping, 6.2% for critical tracking, and 5.2% for the one hole test. The EtOH equivalents at 150 ppm toluene for digit span (0.56g EtOH/kg/body weight), the latency for pattern recognition (0.66 g EtOH kg body weight), and the one hole element "move" (0.37 g EtOH kg body weight) show that the first two measures would be affected at or above the 50 mg% blood alcohol concentration. This concentration is recognised as the lowest alcohol concentration associated with increased numbers of automobile accidents. The results suggest that EtOH may be a useful acute standard to compare the effects of various industrial solvents and support investigating an association between exposure to solvents and increased risk to safety in industry.
TL;DR: An extended follow up of 1221 chromium and nickel exposed welders in the Federal Republic of Germany confirmed an increased relative risk of 1.6 for all cancers compared with an internal reference group of 1694 turners and an inverse relation with time since first exposure.
Abstract: An extended follow up of 1221 chromium and nickel exposed welders in the Federal Republic of Germany confirmed an increased relative risk of 1.6 for all cancers compared with an internal reference group of 1694 turners. In an external comparison an excess of deaths from malignant tumours compared with that expected from the national mortality rates was found (standardised mortality ratio (SMR) = 109), which was clearly related to both time since first exposure and duration of exposure. Mortality from lung cancer was increased among welders (SMR = 113) but also among turners (SMR = 108). The difference remained when the subgroups were compared according to smoking information. A large excess of mesothelioma as a cause of death could be attributed to exposure to asbestos. The significantly increased SMR seen for urogenital tumours and "other or unspecified tumours" showed, however, an inverse relation with time since first exposure. This and other inconsistencies in the analysis by type of welding do not permit conclusive statements. Thus a further extension of follow up seems warranted.
TL;DR: The findings suggest that even at environmental exposure levels calcium metabolism is gradually affected, as cadmium accumulates in the body, and the morbidity associated with this phenomenon in industrialised countries remains presently unknown.
Abstract: The objective was to investigate the hypothesis that environmental exposure to cadmium may affect calcium metabolism in the population at large. The 1987 participants (965 men and 1022 women), from 20 to 80 years old, constituted a random sample of the population of four Belgian districts. The urinary excretion of cadmium, a measure of lifetime exposure, averaged 9.3 nmol/24 h in men (range 0.4-324 nmol/24 h) and 7.1 nmol/24 h (range 0.1-71 nmol/24 h) in women. Serum alkaline phosphatase activity and the urinary excretion of calcium correlated significantly and positively with urinary cadmium excretion in both men and women, and serum total calcium concentration negatively with urinary cadmium excretion in men only. The regression coefficients obtained after adjustment for significant covariates indicated that when urinary cadmium excretion increased twofold, serum alkaline phosphatase activity and urinary calcium excretion rose by 3-4% and 0.25 mmol/24 h respectively, whereas in men serum total calcium concentration fell by 6 mumol/l. After adjustment for significant covariates the relation between serum total calcium concentration and urinary cadmium excretion was not significant in women. The findings suggest that even at environmental exposure levels calcium metabolism is gradually affected, as cadmium accumulates in the body. The morbidity associated with this phenomenon in industrialised countries remains presently unknown and requires further investigation.