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Biomedical subjects

A Tossavainen

Publications and source records attributed to A Tossavainen.

At least 19 recordsLinked to original sources
PubMed1997

Exposure to soluble nickel in electrolytic nickel refining.

Past and present exposure to nickel was studied in an electrolytic nickel refinery, where an increased incidence of nasal cancer had been reported, using nickel analyses in air, blood and urine. Genotoxic effects were studied using analysis of micronuclei from acridine orange-stained smears from the buccal mucosa of the workers. Workers used respirators or masks in tasks where the exposure was expected to be high. Inside the mask, nickel concentrations were 0.9-2.4 micrograms m-3 in such tasks. In those tasks where masks were not used, nickel concentrations in the breathing zone were 1.3-21 micrograms m-3. Air-borne nickel concentrations (stationary sampling) varied between 230 and 800 micrograms m-3 in 1966-1988 with no systematic change; thereafter lower concentrations (170-460 micrograms m-3) have been observed. After-shift urinary concentrations of nickel were 0.1-2 mumol l-1; they showed no correlation with nickel concentrations in the air. Concentrations of nickel in the urine were still elevated after a 2-4 week vacation. The frequency of micronucleated epithelial cells in the buccal mucosa of nickel refinery workers was not significantly elevated by comparison with referents. No relationship was observed between micronucleus frequencies and levels of nickel in air, urine or blood.

Air Pollutants, Occupational↗
PubMed1997

Occupational exposure to nickel salts in electrolytic plating.

An occupational hygiene survey was made in 38 nickel plating shops in Finland and exposure to nickel was studied by means of biological measurements and, in three shops, by using air measurements. The average after-shift urinary nickel concentration of 163 workers was 0.16 mumol l.-1 (range 0.001-4.99 mumol l.-1). After the 1-5 week vacation the urinary nickel concentration was higher than the upper reference limit of non-exposed Finns indicating that a part of water-soluble nickel salts is accumulated in the body. Urinary nickel concentrations in the shops considered clean in the industrial hygiene walk-through were not different from those observed in the shops considered dirty. The correlation between the concentrations of nickel in the air and in the urine was low, and the amount of nickel excreted in the urine exceeded the calculated inhaled amounts, indicating exposure by other routes such as ingestion.

Adult↗
PubMed1996

Screening for asbestos-induced diseases in Finland.

Screening for asbestos-induced diseases in Finland was carried out in 1990-1992 as a part of the Asbestos Program of the Finnish Institute of Occupational Health. The aim of the present study was to find the workers who had developed an asbestos-induced disease in certain occupations. Examination of active or retired workers included a personal interview on work history and asbestos exposure, and a chest X-ray. The target group for the screening comprised workers under 70 years of age who had worked at least for 10 years in construction, 1 year in a shipyard or in the manufacture of asbestos products. A preliminary questionnaire was sent to 54,409 workers, 18,943 of whom finally participated in the screening examination. The mean age of the workers was 53 years; 95% were employed in construction, 2% in shipyards, and 3% in the asbestos industry. The criteria for a positive screening result were (1) a radiographic finding clearly indicating lung fibrosis (at least ILO category 1/1), (2) a radiographic finding indicating mild lung fibrosis (ILO category 1/0) with unilateral or bilateral pleural plaques, (3) marked abnormalities of the visceral pleura (marked adhesions with or without pleural thickening), or (4) bilateral pleural plaques. The positive cases totalled 4,133 (22%) and were sent for further investigation. In addition to the screening, information on the presence of asbestos in the work environment, prevention of asbestos exposure, as well as on the health effects of asbestos exposure and smoking were given to the participating workers. The screening acted as a preliminary survey to prompt further national follow-up of asbestos-induced diseases among the workers who have been exposed to asbestos. This article presents the material, methods, and overall results of the screening.

Adult↗
PubMed1996

Radiographic small lung opacities and pleural abnormalities in relation to smoking, urbanization status, and occupational asbestos exposure in Finland.

The role of smoking and an urban living environment in the etiology of radiographic pleural and pulmonary abnormalities was studied in a population sample that was representative of the Finnish adult population. A total of 7095 full-size chest radiographs were classified according to the International Labor Organization's 1980 classification of radiographs of pneumoconioses, with some modifications. The risk of bilateral pleural plaques was significantly higher among urban men (RR, 2.0) and women (RR, 3.8), even when adjusted for age and probability of occupational asbestos exposure and smoking. The risks of small lung opacities and abnormalities of the visceral pleura were not higher in urban areas. Risks of small lung opacities and thickening of the visceral pleura were positively associated with smoking, and the risk of small lung opacities was also higher among smokers than never-smokers in the population fraction with unlikely occupational asbestos exposure.

Adult↗
PubMed1995

Finnish Institute of Occupational Health Asbestos Program 1987-1992.

In 1987-1992, the Finnish Institute of Occupational Health (FIOH) implemented a nationwide asbestos program aimed at preventing asbestos-related risks in good cooperation with governmental authorities, industry, trade unions, the health care and insurance systems, and mass media. The goals were to minimize all exposure to asbestos, identify people exposed at work, and improve the diagnostics of asbestos diseases, especially cancers. The program entailed several concrete actions and extensive dissemination of information, training, services, and scientific research. As proposed by the State Asbestos Committee, new use of asbestos products was banned and strict regulations were applied to renovation and inspection of old buildings. The screening study of asbestos-induced diseases included 18,943 current and retired workers from house building, shipyard, and asbestos industries. Pleural and parenchymal changes were found in 4,133 persons (22%), who were referred to further clinical examinations as suspected cases of an occupational disease. It was estimated that past exposure of asbestos among the Finnish population of 5 million causes > 150 mesotheliomas and lung cancers annually, totalling > 2,000 asbestos-induced cancer deaths by the year 2010. Although several major control actions were made or started during the program, the bulk of the preventive work still lies ahead.

Asbestosis↗
PubMed1995

Radiographic small lung opacities and pleural abnormalities as a consequence of asbestos exposure in an adult population.

OBJECTIVES: The purpose of this study was to estimate the role of past asbestos exposure as a cause of radiographic small lung opacities and pleural abnormalities in the Finnish adult population. METHODS: The study was conducted in 1978-1981 and was based on a population sample (N = 8000) representative of the Finnish population aged 30 years or over. Full-size chest radiographs and a complete job title history were available for 3811 women and 3274 men. The radiographs were classified according to the 1980 classification of radiographs of pneumoconioses published by the International Labour Office and the work histories according to the probability of occupational asbestos exposure. Age- and smoking-adjusted relative risks of radiographic parenchymal and pleural abnormalities were calculated with the analysis of covariance according to the probability of asbestos exposure. RESULTS: About 13% of the men and 0.8% of the women were classified as probably exposed to asbestos. There was more than 90% agreement in the repeated work history evaluations. The risk of small lung opacities was significantly increased among the probably exposed men [risk ratio (RR) 1.7 for ILO profusion category 1/1 or more and RR 1.6 for profusion category 1/0]. The risk of pleural plaques was increased both among the men (RR 3.0) and the women (RR 4.8) with probable exposure. The risk of thickened horizontal interlobar fissure was also increased among the probably exposed men (RR 1.7). Among the men, the etiologic fraction attributable to occupational asbestos exposure was about 30% for small lung opacities, about 40% for pleural plaques, and about 20% for thickened horizontal fissure. Among the women the etiologic fractions for asbestos were similar for pleural abnormalities, but much lower for parenchymal ones. CONCLUSIONS: Occupational asbestos exposure has been common among Finnish men, and it plays a significant role in the etiology of both pleural and parenchymal abnormalities also at the level of the general population.

Adult↗
PubMed1995

Silica, silicosis and cancer in Finland.

Approximately 100 000 Finnish workers are currently employed in jobs and tasks that may involve exposure to airborne silica dust. The major industries involved are mining and quarrying; production of glass, ceramics, bricks and other building materials; metal industry, particularly iron and steel founding; and construction. Over 1500 cases of silicosis have occurred in Finland since 1935. Tuberculosis has been a frequent complication of silicosis. Results of studies from several countries strongly suggest that silica dust also causes lung cancer. The results of the relevant Finnish epidemiologic and industrial hygiene studies addressing cancer risk and exposure to quartz dust are summarized.

Confidence Intervals↗
PubMed1994

Pleural plaques and exposure to mineral fibres in a male urban necropsy population.

OBJECTIVES: The study aimed to evaluate the risk of pleural plaques according to the degree of past exposure to asbestos, type of amphibole asbestos, and smoking, as well as to estimate the aetiologic fraction of asbestos as a cause of plaques among urban men. METHODS: The occurrence and extent of pleural plaques were recorded at necropsies of 288 urban men aged 33 to 69 years. The pulmonary concentration of asbestos and other mineral fibres was analysed with scanning electron microscopy. The probability of past exposure was estimated from the last occupation. RESULTS: Pleural plaques were detected in 58% of the cases and their frequency increased with age, probability of past occupational exposure to asbestos, pulmonary concentration of asbestos fibres, and smoking. The risk of both moderate and widespread plaques was raised among asbestos exposed cases, and the risk estimates were higher for widespread plaques than for moderate plaques. The age adjusted risk was higher for high concentrations of crocidolite/amosite fibres than for anthophyllite fibres. The aetiologic fraction of pulmonary concentration of asbestos fibres exceeding 0.1 million fibres/g was 43% for widespread plaques and 24% for all plaques. The median pulmonary concentrations of asbestos fibres were about threefold greater among cases with widespread plaques than among those without plaques. No increased risk of pleural plaques was associated with raised total concentrations of non-asbestos fibres. CONCLUSION: The occurrence of pleural plaques correlated closely with past exposure to asbestos. The risk was dependent on the intensity of exposure. Due to methodological difficulties in detecting past exposures to chrysotile and such low exposures that may still pose a risk of plaques, the aetiologic fractions calculated in the study probably underestimate the role of asbestos.

Adult↗
PubMed1994

Retention of asbestos fibers in the human body.

The number, type, and size of retained asbestos fibers were measured by scanning electron microscopy (SEM) in lung tissues of 10 workers who had died from lung cancer or mesothelioma. The levels were 190-3000 x 10(6) fibers/g of dry tissue in three crocidolite sprayers, 6-39 x 10(6) fibers/g of dry tissue in two asbestos product workers and 13-280 x 10(6) fibers/g of dry tissue in five insulators exposed to anthophyllite. The duration of past exposure corresponding to the limit of 1 million fibers/g of dry tissue was 1 to 2 days in spraying, 3 to 10 days at the production plant and 1 to 4 months in insulation work. No long-term clearance of amphibole fibers, > 5 microns in length, could be demonstrated. In one of the sprayers the fiber concentrations of lung parenchyma, visceral and parietal pleura, hilar lymph nodes, and kidney cortex were orders of magnitude higher than in a series of unselected autopsies. The size and aspect ratio of crocidolite fibers in various tissues were similar, indicating that the translocation processes are rather unselective in respect to fiber dimensions.

Adult↗
PubMed1994

Is there an association between pleural plaques and lung cancer without asbestosis?

OBJECTIVES: A recent review or meta-analysis of epidemiologic studies concluded that persons with asbestos-related pleural plaques do not have an increased risk of lung cancer in the absence of parenchymal asbestosis. The reviewer inferred that this conclusion provided indirect supportive evidence for the proposition that asbestosis is a necessary precursor of asbestos-related lung cancer. The objective of the present communication is to contest these claims. METHODS: Finnish epidemiologic data and population statistics were used to estimate the apparent risk ratio of lung cancer associated with radiographic signs of pleural plaques. Power calculations were applied to compute the needed population sizes to demonstrate that the association is statistically significant. RESULTS: Unrealistically large population studies would be needed to observe the statistical relation between pleural plaques and lung cancer, quantitated as a risk ratio of 1.1, resulting from relatively low levels of environmental asbestos exposure. In realistic and valid epidemiologic studies on heavily exposed subpopulations, a two- or threefold risk can be identified. CONCLUSIONS: Uninformative studies should not be interpreted as providing suppressive evidence that pleural plaques are a noncausal risk indicator of lung cancer. Even for the null hypothesis, the inference that asbestosis is a necessary causal link between asbestos and lung cancer is illogical.

Adult↗
PubMed1994

Asbestos exposure and pulmonary fiber concentrations of 300 Finnish urban men.

OBJECTIVES: The aim of the study was to determine the pulmonary concentrations of mineral fibers in the Finnish male urban population and to evaluate the analysis of pulmonary fiber burden by scanning electron microscopy (SEM) as an indicator of past fiber exposure. METHODS: The pulmonary concentration of mineral fibers was determined by SEM and compared with occupational history for a series of 300 autopsies of urban men aged 33 to 69 years. RESULTS: The concentration of fibers (f) longer than 1 micron ranged from < 0.3 to 163.10(6) per gram of dry tissue (f.g-1). Asbestos fiber concentrations exceeding 1.10(6) f.g-1 were observed in 33% of the cases with probable occupational exposure to asbestos and 1% of the cases with unlikely occupational exposure. Even asbestos fiber concentrations of 0.3 to 1.10(6) f.g-1, especially of crocidolite-amosite fibers, were rare among the men with unlikely occupational exposure. Fiber concentrations exceeding or equaling 1.10(6) f.g-1 were 10 times more frequent among the men more than 60 years of age as compared with those less than 40 years of age. Inorganic fibers other than asbestos had a weaker correlation with occupational history and age. Smoking habits had no significant effect on the pulmonary fiber counts. CONCLUSIONS: Asbestos fiber concentrations exceeding 1.10(6) f.g-1 are highly indicative of past occupational exposure to asbestos. The distribution of fiber concentrations in the different age groups of this study indicated decreasing asbestos exposure in Finland since the 1970s.

Adult↗
PubMed1993

Asbestos exposure according to different exposure indices among Finnish lung cancer patients.

During a 6-month period all lung cancer patients in a university hospital chest clinic were investigated for asbestos exposure by means of personal interview, bronchoalveolar lavage (BAL), roentgenograms, lung function testing, histology and measurement of fibre concentrations in lung tissue samples using scanning electron microscopy (SEM). About one-third of the patients (33%) were classified as having been exposed to asbestos on the basis of the interview. BAL was performed and AB counts were done in 51 patients. Fourteen (27%) BAL specimens had AB counts of 1 or more AB/ml, which is the conventional limit for non-trivial asbestos exposure. For a subgroup of 25 operated lung cancer patients fibre analysis was also available. In six cases (30%) the asbestos-containing samples had asbestos fibre concentrations equal to or more than 1 million fibres/g dry lung. In eight (32%) of the operated lung cancer patients histopathologically confirmed fibrosis was seen; five of these patients were in the two highest exposure classes. Pleural plaques on X-ray films were seen in six (24%) of the operated cases. With each indicator of exposure about 30% of lung cancer patients were found to have been exposed, confirming the "one-third rule"; however, when all the information was collated there were three cases (12%) in which exposure was most obvious according to the different parameters used in this study. In these three cases the cancer could well be attributed to asbestos. Anthophyllite was present in all asbestos-containing samples and anthophyllite was the main fibre type in 61% of these samples.

Adult↗
PubMed1992

Urinary and blood manganese in occupationally nonexposed populations and in manual metal arc welders of mild steel.

To obtain reference values for blood and serum manganese levels, blood specimens were collected from 29 men and 36 women. Mn in blood showed a normal distribution; its upper 97.5% limit in blood was 0.38 mumol/l. Mn in serum showed a skewed distribution, which did not differ from the normal one after logarithmic transformation. The respective reference limit was 19 nmol/l. In both specimens, the levels of Mn were significantly lower in men than in women. To obtain reference values for Mn in urine, midday urine specimens were collected from 58 men and 96 women. Mn in urine also showed a skewed distribution, and the upper 97.5% limit was 38 nmol/l. The levels of Mn in blood and urine were statistically significantly higher in manual metal arc (MMA) welders of mild steel (MS) than in the reference populations. Five MMA/MS welders were subjected to a further study in which the ambient intramask Mn levels and urinary Mn excretion were monitored throughout a full working week. For two welders the correlation of Mn in urine specimens voided in the afternoon was good with the before noon Mn concentrations in the hygienic measurements; for the rest the correlation was minimal. Mn in diurnal urine specimens collected in six portions showed fluctuation if specific gravity or creatinine in urine was used to standardize for the urinary flow, but it was less evident for urinary Mn excretion rate. Our results seem to indicate that the measurement of Mn in urine or blood may be used for monitoring Mn exposure in MMA/MS welders only at the group level.

Adolescent↗
PubMed1991

Relative risk of mesothelioma associated with different levels of exposure to asbestos.

The relative risk of mesothelioma associated with different levels of exposure to asbestos was evaluated. The exposure was assessed from work histories of 51 mesothelioma cases and 51 sarcoidosis referents. The lung fiber concentration of the mesothelioma patients was compared with that of two reference groups (13 random autopsy cases and 43 male lung cancer patients). When the categories definite and probable were used as an estimated probability of occupational exposure, an odds ratio of 17.7 [90% confidence interval (90% CI) 3.4-253] and 3.0 (90% CI 0.9-10.6), respectively, was obtained. A lung fiber concentration of greater than 1 million fibers/g of dry tissue as an indicator of accumulated exposure gave an odds ratio of 14.4 (90% CI 2.5-178) for the men in comparison with the autopsy cases and 3.1 (90% CI, 1.3-7.5) in comparison with the lung cancer patients. Elevated risk of mesothelioma was shown to be associated with a lung fiber concentration of greater than 1 million fibers/g of dry tissue.

Adult↗