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Biomedical subjects

O Axelson

Publications and source records attributed to O Axelson.

At least 127 records · Page 7Linked to original sources
PubMed1987

Pesticides and cancer risks in agriculture.

The work environment in agriculture is complex, with many potentially hazardous exposures, but the overall mortality from cancer and other causes is rather low among farmers. However, several studies have consistently indicated an excess of certain cancer forms. Lymphomas, leukemias, multiple myeloma and also malignancies of connective tissue attract special interest, as being possibly associated with the use of pesticides. Phenoxy acid herbicides may play an etiological role, especially for non-Hodgkin's lymphoma, whereas the findings are more ambiguous for Hodgkin's disease and soft-tissue sarcoma, perhaps indicating an interaction with co-factors. The issue has been controversial for many years, however, and one of its aspects involves the use of phenoxy acids in the Vietnam war. Furthermore, DDT has been associated with lung cancer in mixed exposure situations, and with chronic lymphatic leukemia. Arsenical pesticides may have caused skin cancer in vine-growers. Further studies, especially of specific user groups and producers, may avoid the complex exposure situation in agriculture.

Agricultural Workers' Diseases↗
PubMed1987

Mortality and cancer incidence among workers in an abrasive manufacturing industry.

Earlier epidemiological studies have shown that exposure to aluminium oxide and silicon carbide might carry with it an increased risk of lymphomas, stomach cancer, and non-malignant respiratory disease. To elucidate further this possible hazard, the cancer morbidity and the total mortality pattern was studied among 521 men manufacturing abrasive materials who had been exposed to aluminium oxide, silicon carbide, and formaldehyde. Total dust levels were in the range of 0.1-1.0 mg/m3. The cohort was followed up from 1958 until December 1983. No significant increase was found in total mortality, cancer mortality, or incidence of non-malignant respiratory diseases.

Aluminum Oxide↗
PubMed1987

Mortality in the Swedish glassworks industry.

An earlier, relatively small case-referent study has shown an increased risk for glassworks employees to die from stomach cancer, lung cancer, and cardiovascular disorders. This observation suggested an extended study virtually covering the entire glass-producing industry of Sweden. This new study confirmed the earlier results and, furthermore, an excess risk for colon cancer was also identified. No deviation was found in the cancer mortality pattern for all men in the glass-producing area compared to the whole of Sweden. The grouping of glassworks employees according to type of metal consumption at the glassworks showed the excess risks of stomach cancer, colon cancer, and cardiovascular deaths to relate to glassworks with a high consumption of lead, arsenic, antimony, and manganese. However, the strong correlation of these various metal exposures did not permit any successful separation of the effects of the different metals. For cardiovascular mortality, as for cancer, the glassblowers especially suffered from increased risk. Their exposure might, to a great extent, be oral, involving the glassblower's pipe as a "vector" for the exposure to various metals.

Aged↗
PubMed1986

Silica, silicosis and lung cancer among ceramic workers: a case-referent study.

A case-referent study has been carried out regarding a possible connection between silica exposure and lung cancer (ICD 162) in Central Italy, where the pottery industry has a long tradition. Silicosis among 72 cases of lung cancer and among 314 referents, all deceased, was ascertained through checking the individual files of compensated cases of silicosis. Questionnaires on past employments and smoking habits were blindly administered to the next-of-kin of the deceased subjects. Controlling for age, period of death, and smoking, workers in the ceramic industry were found to have a higher lung cancer risk than workers in other occupations free from silica exposure (Mantel-Haenszel rate ratio = 2.0; 95% confidence interval (CI) = 1.1-3.5). This increased risk was mainly due to a rate ratio of 3.9 (95% CI = 1.8-8.3) for silicotic individuals, while for nonsilicotic ceramic workers it was only 1.4 (95% CI = 0.7-2.8). The result of this study seems to suggest that lung cancer might be merely indirectly associated with exposure to silica through the silicotic process, although the dose may differ for silicotic and nonsilicotic individuals.

Ceramics↗
PubMed1986

Cancer mortality among leather tanners.

Workers were studied at a tannery that operated from 1873 to 1960, once one of the biggest in Scandinavia. The results show a slight numerical increase of deaths from cancer of the stomach and a significant, threefold excess mortality from cancer of the pancreas. Even in view of critical questions about validity it seems likely that this excess might be related to exposure to chemicals in tannery work.

Aged↗
PubMed1986

A review of porphyria and cancer and the missing link with human exposure to hexachlorobenzene.

A literature review shows that porphyria cutanea tarda (PCT), and possibly acute intermittent porphyria also, tend to occur more often than expected among cases of primary liver cancer, especially when cirrhosis is present. Lymphomas and PCT may be related also, although this is less well documented. Furthermore, there is an interesting report on a case of PCT, sarcoma and probable exposure to 2,3,7,8-tetrachlorodibenzo-para-dioxin. Exposure to hexachlorobenzene (HCB) as a cause of cancer in humans does not seem to have been reported, however, but exposure to this compound and other chlorinated aromatics should be included in future observations of PCT and cancer. The possibilities for good epidemiological studies of HCB exposure in relation to cancer and other effects seem to be limited although some guidelines can be given.

Chlorobenzenes↗
PubMed1985

Mortality pattern in a glass producing area in SE Sweden.

Because of discharges, mainly of lead, from glassworks in an otherwise rural and unpolluted area in southeast Sweden the population became concerned about the potential risks of cancer and an epidemiological study was requested. The total and the specific cancer mortality in the three parishes around the glassworks were found to be approximately normal, both by comparison with national death rates and the death rates of another, similarly rural, area. More interesting results, however, were obtained in several case-referent studies also undertaken to study mortality from specific cancer sites and cardiovascular disease with regard to employment in the glassworks. A significant excess of deaths from stomach cancer, especially in glassblowers, lung cancer, and cardiovascular disease was observed among the glassworkers. Occupational exposures in the glassworks, especially to arsenic, may be of aetiological importance.

Cardiovascular Diseases↗
PubMed1985

Dealing with the exposure variable in occupational and environmental epidemiology.

Whereas the outcome variable in epidemiologic research is usually well-defined, the exposure is more diffuse, complex and variable, involving components of both intensity and duration. Usually, the time integral of the intensity has been used as a measure of exposure, e.g. working level months, fibre-years, etc. Toxicological models have suggested, however, that greater importance should be accorded to early exposure in cancer epidemiology, while the recent exposure may be more important as regards the development of some other types of disorders. A simplified approach in cancer epidemiology would be to consider the exposure within a time-window or otherwise allow for induction-latency time. For the practical assessment of exposure, so-called job exposure matrices might be of value, especially if recall bias is suspected, but on the other hand, there is rather little objective indication in the literature that serious recall bias is a major problem in case-referent studies.

Dose-Response Relationship, Drug↗
PubMed1985

The case-referent study--some comments on its structure, merits and limitations.

Case-referent (case-control) studies have become increasingly important in occupational health epidemiology. The concept of study base [Miettinen, Scand J Work Environ Health 8 (1982):suppl 1, 7-14] as referring to the health experience of the study population over time, and a clear recognition of open and closed populations, ie, with or without turnover, make the structure of the case-referent study clearer. The referents should represent the study base in terms of exposure and nonexposure and even with regard to other determinants of the disease under study. Case-referent studies refer to open populations unless nested in cohorts. Matching in cohort studies is straight-forward and creates a symmetrical situation among the exposed and unexposed with regard to the matching factor, but this symmetry is not achieved in case-referent studies, in which matching tends to distort the representativeness of the referents with regard to the study base. This circumstance suggests that matching on determinants of the disease should be maintained in the analysis. However, since the referents are a sample of the base, there might be confounding in the data, which does not exist in the base and vice versa, ie, full control of confounding in case-referent studies is not achievable either through matching or through any other procedure, but a large sample of referents would more properly reflect the distribution of confounders in the base. Using hospital referents, one has to consider possible relations between the referent diseases and the exposure under study, and therefore evaluation of multiple exposures may even require different sets of hospital referents.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiologic Methods↗
PubMed1984

Clinical studies of psychoorganic syndromes among workers with exposure to solvents.

Exposure to organic solvents is common in industry. In Sweden, patients being evaluated for suspected solvent-related diseases now constitute the largest group of patients seen at many clinics of occupational medicine, largely replacing classical occupational disorders. The findings in 128 consecutive patients with solvent exposure have been reviewed for the period 1978-1981. The duration of exposure was 9 years or more for those with a diagnosis of psychoorganic syndrome (POS). "Incipient" POS was seen after a minimum exposure of 3 years duration. Patients with POS also had an increased frequency of polyneuropathy in comparison to those without any signs of POS. It was not possible to link these abnormalities with particular solvent exposure. Clinical chemistry tests were normal except for liver function tests in a few patients.

Adult↗
PubMed1984

Risk factors of coronary heart disease among personnel in a bus company.

A cohort of all the men employed in a bus company was undertaken to elucidate possible adverse health effects of diesel exhaust exposure. The results showed that the most heavily exposed group (bus garage workers) had a fourfold increase in risk of dying from cardiovascular disease, even after correction for smoking, and allowing for at least 10 years of exposure and 15 years or more of induction-latency time. The findings are in accordance with the hypothesis of a possible connection between exposure to carbon monoxide and cardiovascular disease.

Carbon Monoxide Poisoning↗
PubMed1984

Room for a role for radon in lung cancer causation?

Reduced ventilation due to energy saving has focussed interest on a potential lung cancer risk from increased indoor concentrations of alpha-emitting radon and radon daughters, escaping from building materials and from the ground. Some preliminary studies now also indicate a hazard to be present as related to radon daughter exposure in homes. However, the indoor radon daughter levels have probably been continuously increasing for half a century, especially in colder climates, due to the introduction of central heating instead of stoves and open fire places, reducing thermal ventilation. Furthermore, in our time, many people have got additional exposure through extended indoor work time instead of earlier outdoor activities in farming etc. The steeply increasing lung cancer rates over the past decades as well as the various oddities affecting the relationship between smoking and lung cancer, e.g. the urban-rural difference in lung cancer risk, also after standardization for smoking, the influence of immigration on lung cancer morbidity as well as the varying rates over the world and other observations, would obtain simple explanations by taking radon daughter exposure into account in addition to smoking. Then, also some curious and hitherto unexplained "inverse" relationships between lung cancer and inhalation of cigarette smoke or bronchitis in air-polluted areas, respectively, would become understandable.

Animals↗
PubMed1984

Radon in homes--a possible cause of lung cancer.

An earlier case-referent study [Scand j work environ & health 5 (1979) 10-15] has indicated a possible relationship between lung cancer and exposure to radon and radon daughters in dwellings. Indoor radon concentrations seem to depend on both building material and leakage of radon from the ground. This new study, in a rural area, is a further attempt to elucidate the etiology of lung cancer, taking into consideration type of house and ground conditions, as well as smoking habits. Although the choice of a rural study population helped to eliminate various confounding exposures in the urban environment, it limited the size of the study because of the rareness of lung cancer in rural populations. Long-term residents, 30 years or more in the same houses, were studied, and again an association was found between lung cancer and estimated exposure to radon and radon daughters in homes. The data also seem to indicate the possibility of a multiplicative effect between smoking and exposure to radon and radon daughters in homes, but there was also some confounding between these factors in the data.

Adult↗
PubMed1984

Mortality from cardio-cerebrovascular diseases among dynamite workers--an extended case-referent study.

Increased mortality from cardio-cerebrovascular diseases among male dynamite workers was reported in 1977 and was supported two years later by findings in a small cohort study from another Swedish dynamite population. The excess risk was confined to those with long-term employment. The original case-referent study comprised the years between 1955-1975 and the register of deaths and burials in the parish around the dynamite factory was used as the source of subjects. The same register has now been used for the time period 1976-1980. We have used identical requirements for this extension as in the original study, i.e., confined to men with more than one year of employment and aged 36-70. Cases were those who died from ischaemic heart diseases and cerebrovascular diseases according to WHO classification rules and referents those who died from all other diseases remaining after the primary exclusions. 102 men had died in the parish during the extension period. 15 were excluded. There were 36 deaths from heart diseases, 12 from cerebrovascular diseases and 39 referent diagnoses. Six of the "heart-cases", three of the "c-v-cases" and six of the referents were exposed. The Mantel-Haenszel estimation of the risk ratio for cerebrovascular diseases during the period 1955-80 is 2.9 (95% confidence interval 0.9-6.4) and 2.7 for cardio-vascular diseases (1.4-5.4). Among 25 men exposed more than 20 years only one died from anything else but a cardio-cerebrovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

On the problem of controlling confounding in case-referent studies.

Individuals in various exposure categories constitute an epidemiological study population and its health experience over time can be taken as the base of the study, which is either open with a turnover of individuals (deaths, migrations etc) or closed, when encompassing only originally defined individuals. In cohort studies all individuals are known in terms of membership and exposure, whereas case-referent (case-control) studies utilize a sample from the base, the referents, for information about the exposed and non-exposed domains of the base, and the referents are a sort of relative denominators for the cases. An association in the base between the exposure and another determinant of the disease means confounding and can be fully accounted for in the cohort approach, but not in the case-referent study as relying on a sample of the base. The reason is that the occurrence of the confounder among the referents is influenced by random variation in the sampling procedure and the referents may therefore not always reflect the true situation with regard to confounding in the base. Computer simulations of the acquisition process of referents illustrate that neither a confounded nor a non-confounded base might always be properly reflected in case-referent data. However, the variation of the confounding rate ratio (the crude rate ratio/SMR) might not be expected to vary by more than about a factor of two. Particularly in nested case-referent studies, a relatively large number of referents helps stabilize the random variation, but only the cohort approach provides full control of confounding, a fact, that becomes the more important, the smaller the effect under study.(ABSTRACT TRUNCATED AT 250 WORDS)

Computers↗