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Biomedical subjects

O Axelson

Publications and source records attributed to O Axelson.

At least 73 records · Page 4Linked to original sources
PubMed1994

Comparison of information sources for case-referent data.

OBJECTIVES: Exposure assessment and the ascertainment of cases are topics of main concern in epidemiologic research. To investigate validity aspects of this kind practically, a comparative evaluation was performed of information sources for case-referent data. METHODS: Cases of Hodgkin's disease and non-Hodgkin's lymphoma diagnosed in 1975-1984 were collected from the Regional Cancer Register in Linköping. The study population was restricted to men 20-80 years of age at diagnosis. Living cases included in a previous case-referent study and the complementary cases from the register were compared with regard to the exposures indicated by job title and industrial branch, as given in the National Population Census in 1975. Furthermore, questionnaire-based exposure information from the case-referent study was compared with exposures derived from census information. RESULTS: Only 21% of all of the cases in the study base had been included in the questionnaire-based case-referent study. No major differences in the distribution of exposure were found for the two case series, except that fewer subjects were economically inactive in the previous case-referent study. No clear relations appeared between survival and particular exposures. Risk estimates derived from the present cancer register study were compared with corresponding estimates from the previous case-referent study. With restriction to only economically active cases, the risk estimates approached those of the case-referent study. CONCLUSIONS: This comparison showed that incomplete ascertainment of cases in a case-referent study was not an important source of bias, at least not in relation to what could be achieved by more complete case ascertainment through register linkage.

Adult↗
PubMed1994

Some recent developments in occupational epidemiology.

Occupational epidemiology has grown rapidly since the late 1970s. Case-referent studies have become popular, but more recent development relates to analyses of cohort data. Length of follow-up and employment status can now be adjusted for in such analyses. Attention should also be given to "time windows" of relevant exposure, not only in cancer studies. In cross-sectional studies of common diseases, the prevalence rate ratio should be used rather than the currently popular but unintelligible odds ratio as obtained by logistic regression. Exposure assessment should involve measures that would best reveal an existing risk and dose-response relationships. New achievements in molecular biology are currently influencing the development in occupational epidemiology. Not only DNA (or protein) adducts as markers of exposure or early effect, but also the possibilities to use data on metabolic polymorphism to identify genetically susceptible individuals attract interest. Activated oncogenes and inactivated tumor suppressor gene are useful for subspecifying various cancer types so as to obtain more sensitive studies.

Biomarkers↗
PubMed1994

Updated and expanded Swedish cohort study on trichloroethylene and cancer risk.

There is limited evidence for mutagenicity and carcinogenicity of trichloroethylene (TRI) in experimental test systems. Whether TRI is a human carcinogen is unclear, however. This paper presents an update and extension of a previously reported cohort of workers exposed to TRI, in total 1670 persons. Among men (n = 1421), the overall standardized mortality ratio (SMR) and cancer morbidity ratio (SIR) were close to the expected, with SMR, 0.97; 95% confidence interval (CI), 0.86 to 1.10; and SIR, 0.96; 95% CI, 0.80 to 1.16, respectively. The cancer mortality was significantly lower than expected (SMR, 0.65; 95% CI, 0.47 to 0.89), whereas an increased mortality from circulatory disorders (cardiovascular, cerebrovascular) was of borderline significance (SMR, 1.17; 95% CI, 1.00 to 1.37). No significant increase of cancer of any specific site was observed, except for a doubled incidence of nonmelanocytic skin cancer without correlation with the exposure categories. In the small female subcohort (n = 249), a nonsignificant increase of cancer and circulatory deaths was observed (SMR, 1.53 and 2.02, respectively). For both genders, however, excess risks were largely confined to groups of workers with lower exposure levels or short duration of exposure or both. It is concluded that this study provides no evidence that TRI is a human carcinogen, ie, when the exposure is as low as for this study population.

Adult↗
PubMed1993

Do occupational factors influence the risk of colon and rectal cancer in different ways?

BACKGROUND: Occupational exposures and physical activity have been considered as risk factors for the development of colorectal cancer. METHODS: A case-control study on working conditions and the risk of colon and rectal cancer was performed in southeastern Sweden during 1984-86. Involved were 177 patients, 98 with colon cancer and 79 with rectal cancer, and two groups of control subjects, 371 hospital control subjects and 430 population control subjects. RESULTS: A significantly decreased risk of left-sided colon cancer was observed in persons involved in more than 20 years of physically active work and a significantly decreased risk of rectal cancer in persons involved in more than 20 years of sedentary work. A tendency toward increased risk was seen for colon cancer in male railroad workers and in male gas station workers. A reduced risk of rectal cancer was found for drivers, textile workers, and administration workers, whereas an increased risk of rectal cancer appeared among paper workers and assistant nurses. A low risk of both colon and rectal cancer was found among construction workers and forestry workers. Exposure to asbestos carried a slightly increased risk of colon cancer, whereas exposure to solvents slightly decreased the risk of rectal cancer. CONCLUSION: This study confirms earlier findings that physical activity decreases the risk for left-sided colon cancer, but also suggests that occupational factors influence the risk of colon and rectal cancer in different ways.

Adenocarcinoma↗
PubMed1993

Determinants of papillary cancer of the thyroid.

Determinants of papillary thyroid cancer were evaluated in a questionnaire-based case-control study from southeastern Sweden. A total of 104 cases, diagnosed from 1977 to 1987, and 387 randomly selected controls were included in the analyses. Female subjects with papillary cancer reported a work history as dentists/dental assistants, telephone operators, teachers, and day nursery personnel, and an occupational contact with chemicals and video display terminals more often than did controls. The 11 male cases more often reported working as mechanics and metal workers and having occupational contact with solvents. Other factors associated with increased risk for female papillary cancer were having private well water at the birth address; leisure time exposure to combustion smoke; low intake of cruciferous vegetables and seafood; and a family history of goiter, heart disease, biliary disorder, or female genital cancer. Diagnostic radiographic examinations, especially to the head, neck, or upper back/chest area, or repeated dental examinations, were also found to be associated with this form of cancer. With regard to the possible influence from hormonal factors among women less than age 50 years at time of diagnosis, an increased risk was found for a pregnancy soon after puberty. Tendencies toward a decreasing risk with increasing age at first pregnancy as well as an increasing risk with increasing number of pregnancies were found as well. Multiparity seemed to potentiate the effect from prior radiographic examinations.

Adult↗
PubMed1993

Some occupational exposures as risk factors for malignant lymphomas.

BACKGROUND: Malignant lymphomas (Hodgkin disease [HD] and non-Hodgkin lymphoma [NHL]) have been subject to several epidemiologic studies and found to be associated with various environmental exposures, especially solvents, wood, and phenoxy herbicides. METHODS: Various determinants for HD and NHL were evaluated in a case-referent study encompassing 31 cases of HD, 93 cases of NHL, and 204 referents, all alive. Information on these determinants, mainly occupational exposures, was obtained by mailed questionnaires. RESULTS: Crude odds ratios were increased for various occupational exposures, i.e., exposures to solvents, pesticides, metal fumes, welding, and fresh wood, and nursing. Further analyses based on logistic regression indicated exposure to phenoxy herbicides and fresh wood among sawmill workers, lumberjacks, and paper pulp workers to be significant risk factors for HD. Welding, working as a lumberjack, nursing, and ex-smoking were associated with a significantly increased risk for NHL. Radiographic examinations were negatively associated with HD, as was office work for NHL. CONCLUSIONS: The results were mainly in agreement with the findings of earlier studies, but diverging associations also appeared.

Adult↗
PubMed1993

Radon as a risk factor for extra-pulmonary tumours.

Exposure to radon in uranium and other mines is a well recognised risk factor for lung cancer. There is also increasing evidence of a risk of lung cancer from indoor radon. An excess of stomach cancer has been observed in some mining populations but the role of radon is unclear. A few correlation studies and a case-control study have indicated that exposure to indoor radon could be of some importance as a cause of other tumours, especially acute myeloid leukaemia, melanoma and kidney cancer. Also prostate cancer and some other cancer types have correlated with estimated radon exposure but the relatively few studies are not quite consistent with each other. Nevertheless, the various observations of extra-pulmonary tumours associated with radon exposure may warrant further studies, especially with regard to childhood exposure and cancers.

Air Pollution, Indoor↗
PubMed1993

Indirect estimates of lung cancer death rates in Italy not attributable to active smoking.

We used a model, originally applied in the context of occupational cohort studies to evaluate confounding from smoking, to estimate lung cancer death rates in the Italian population not attributable to active smoking (background rates). Relevant parameters were the percentages of current and former smokers in the population, as derived from national interview surveys, and rate ratios for lung cancer and smoking. We studied differences over time (1956-1958 to 1987-1989) and place (urban/rural) in the background lung cancer death rates while allowing for changes in the average daily amount of tobacco consumption and in duration of smoking. We applied two functions proposed by Whittemore to obtain rate ratios for smokers: one assumes a linear relation between cumulative number of cigarettes smoked and lung cancer death rates; the other is closer to the multistage carcinogenesis theory. All our calculations indicate that the estimated background rates increased in Italy from the period 1956-1958 to the period 1987-1989; the increase was stronger in males than in females. In 1980-1982, higher background rates were observed in heavily urbanized areas than in rural areas. The results did not change when we considered cohort effects in smoking prevalence and when the key parameters were perturbed in a sensitivity analysis. It appears that factors other than smoking play an important role in causing lung cancer in Italy.

Adult↗
PubMed1993

Multiple sclerosis and exposure to solvents, ionizing radiation and animals.

Earlier studies have indicated an association between multiple sclerosis and environmental factors, especially occupational exposure to solvents. The present study examined such relationships further. From medical files of hospitals in Kalmar and Jönköping, 91 cases of multiple sclerosis, diagnosed in 1983-1988, were identified from population registers corresponding to the catchment areas of the hospitals, and 348 referents were randomly drawn. The cases and referents answered a questionnaire concerning occupational exposure and animal contacts. The men had significantly elevated risks, determined from logistic odds ratios, for solvent exposure, occupational contact with dogs or cats, and leisure-time contact with caged birds. X-ray treatment and previous diseases were risk indicators among the women. For the men and women together, solvent exposure, radiological work, and previous diseases were associated with clearly elevated risks. Although the study concerned rather few subjects, the findings indicate that several exogenous factors might contribute to the development of multiple sclerosis.

Adult↗
PubMed1993

Increased urinary excretion of the oxidative DNA adduct, 8-hydroxydeoxyguanosine, as a possible early indicator of occupational cancer hazards in the asbestos, rubber, and azo-dye industries.

Oxidative damage to DNA has been suggested to contribute to a number of diseases including cancer. In order to study the relationship between oxidative damage to DNA and occupational exposures, urinary excretion of the oxidative DNA adduct, 8-hydroxydeoxyguanosine (8-OHdG), was determined in asbestos workers, rubber workers, azo-dye workers and controls. Levels of 8-OHdG in urinary samples were quantified by automated coupled-column high-performance liquid chromatography with electrochemical detection (HPLC-EC). The registered 8-OHdG levels were 1.40 +/- 0.56 mumol/mol creatinine in asbestos workers, 1.48 +/- 0.57 in rubber workers, 1.92 +/- 0.85 in azo-dye workers and 1.07 +/- 0.41 in controls (means +/- SD). Thus, 8-OHdG levels appeared to be significantly higher (p < 0.05) in each of the exposed groups than in the control group. Regression analysis revealed no important association between 8-OHdG excretion, age and smoking. These findings suggest that occupational exposures may contribute to an increased oxidative damage to human DNA and point to the possible use of urinary 8-OHdG assays in biomonitoring of biological effects of chemicals in selected industrial workplaces.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1993

Epidemiologic studies of occupational cancer as related to complex mixtures of trace elements in the art glass industry.

In the art glass industry workers run increased risks of dying from several types of cancer, cardiovascular diseases, and cerebrovascular diseases. This paper considers the diseases of glass workers in relation to exposure to particular elements, a high degree of correlation being found for some of them. Case-referent evaluations showed an association between stomach cancer and exposure to a mixture of elements, namely, arsenic, copper, nickel, and manganese, and to some extent also to lead and chromium. For colon cancer, a clearly increasing trend in risk was seen with increasing use of antimony, and to some extent also with increasing use of lead, the two elements being strongly correlated. For lung cancer no obvious correlation with any metal could be found. In addition, the risk for death from cardiovascular disease was fairly evenly distributed, although slightly more related to increasing consumption of the strongly correlated metals nickel and copper.

Glass↗
PubMed1992

Cereal fiber, calcium, and colorectal cancer.

Food intake during the preceding 15 years was evaluated in detail in 41 patients treated for colorectal cancer and an equal number of matched control subjects by means of a dietary history technique that permitted quantitation of nutrients. Dietary habits of the control group could be compared against two larger groups of 371 hospital control and 430 population control subjects. Patients with cancer, who were interviewed after complete recovery from surgery, consumed more fat, protein, and carbohydrates, and thus more energy, than control subjects although these differences were not statistically significant. Per unit energy, the habitual diet of patients with cancer contained less cereal fiber (P less than 0.001), less riboflavin (P less than 0.05), less calcium (P less than 0.05), and less phosphorus (P less than 0.05) than the diet of the control subjects. A high intake of either cereal fiber, total fiber, calcium, and phosphorus in relation to energy intake was found to be associated with a reduced risk ratio of colorectal cancer. For colon cancer separately, a high intake of calcium and cereal fiber was associated with a reduced risk ratio. For rectal cancer, a high intake of total fiber and cereal fiber was associated with a reduced risk ratio. High alcohol consumption correlated with an increased risk ratio. These data are compatible with previous Scandinavian studies relating food consumption to the incidence and mortality of colorectal cancer.

Aged↗