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Biomedical subjects

G Steineck

Publications and source records attributed to G Steineck.

At least 91 records · Page 5Linked to original sources
PubMed1992

A definition of bias founded on the concept of the study base.

We propose a definition of bias founded on the concept of the study base. The definition is unrelated to the study design, thereby permitting a clear comparison of validity among different study types. Also, it facilitates assessment of bias because it allows bias to be subdivided under mutually exclusive categories. In relation to the study base, the epidemiologic study can be viewed as involving three distinct steps. First, the person-time (study base) is specified for the study. Second, the investigators collect data on disease events and person-time among the exposed and unexposed from the study base. Third, they calculate an estimate of the effect of the exposure using the data. Categories pertaining to each of these three steps will create mutually exclusive categories of bias. We suggest the following terminology: the first step generates confounding, the second results in misclassification and misrepresentation, and the third produces analysis deviation. The total bias is the sum of the confounding, misclassification, misrepresentation, and analysis deviation. We illustrate our proposed epidemiologic theory with examples from various biological settings.

Bias↗
PubMed1992

Aspects of patient care. Interviews with relapse-free testicular cancer patients in Stockholm.

Thirty-nine relapse-free testicular cancer patients were interviewed 1-6 years after completion of chemotherapy, in connection with a study of conditioned nausea. Some structured questions about experiences of diagnosis and treatment were included, but this report also summarizes spontaneously given information. The patients' first contact with a treatment setting appears to be an important determinant of the overall treatment experience. If resources are limited, they are used effectively if concentrated during the initial contact with the patient. Support from relatives and friends was reported as good for 90% of the men during treatment. Thirty-two distressing factors during the treatment period were mentioned; the most severe were nausea and vomiting. Other high-ranking factors were "being restricted for the infusion" and "the smell of food." There is a need for flexibility in ways to prepare and serve food on the ward. Some men argued for more information concerning the disease and chemotherapy; others said they received too much information. Several men suggested that a debriefing talk with the physician and someone from the staff should be arranged 6 months to 1 year after completion of treatment.

Adult↗
PubMed1991

Meat, cooking methods and colorectal cancer: a case-referent study in Stockholm.

The associations between methods of cooking meats and colorectal cancer were examined in a population-based case-referent study performed in Stockholm in 1986-1988. The study included 559 cases and 505 referents. Total meat intake, frequent consumption of brown gravy, and a preference for a heavily browned meat surface each independently increased the risk for colorectal cancer. The relative risks (RR) were higher for rectal than for colon cancer, and for boiled meat (RR colon = 1.7, RR rectum = 2.7) than for meat fried with a medium or lightly browned surface (RR colon = 0.8, RR rectum = 1.1), but the highest risks were for meat fried with a heavily browned surface (RR colon = 2.8, RR rectum = 6.0). The analyses were adjusted for year of birth, gender and fat intake. Further adjustments for total energy, dietary fiber intake, body mass and physical activity had little or no influence on the results. The findings suggest that, in addition to frequent meat intake, a heavily browned meat surface formed when frying meat at high temperatures is important in the etiology of colorectal cancer.

Animals↗
PubMed1991

'Local recurrence' and 'disease-free survival'. Doubtful parameters when comparing non-randomized studies of prostate cancer.

We reviewed recent literature on studies with external radiation of prostatectomy for localized prostate cancer considering the definitions of 'local recurrence' and 'disease-free survival' and the reporting of patients lost to follow-up. Among studies evaluating external radiation, 5/71 (29%) mention that prostate biopsy is used for some patients in determining local recurrence, versus 6/11 (55%) for prostatectomy. Several studies, 15/28 (54%), present figures for disease-free survival without giving a definition of the parameter. In the majority of the reports no comments are made relative to patients lost to follow-up. Three authors consider patients lost to follow-up as dead with disease. Considerations regarding 'local recurrence' and 'disease-free survival' warrant caution in the interpretation of data based on such parameters. In a comparison of non-randomized studies of localized prostate cancer, cancer-specific survival with prostate cancer death defined as 'death wtih diagnosed distant metastases' may be a robust parameter.

Clinical Trials as Topic↗
PubMed1990

Physical activity and colon cancer: a case-referent study in Stockholm.

A population-based case-referent study on physical activity (during working and recreational hours) and colon cancer was performed in Stockholm in 1986-1988. The study included 1,081 subjects. Low physical activity was associated with an excess risk of colon (but not rectum) cancer for both men and women, showing a dose-response relationship with decreasing levels of physical activity. The effect was seen in the left colon (relative risk = 3.2, 95% confidence interval = 1.5-7.0) rather than in the right colon (relative risk = 1.1, 0.5-2.5). These results persisted after adjustment for year of birth, gender, body mass, intake of total energy, protein, total fat, dietary fibre, and browned meat surface.

Adenocarcinoma↗
PubMed1990

Diet, body mass and colorectal cancer: a case-referent study in Stockholm.

A population-based case-referent study on diet (total energy, protein, fat, dietary fiber), body mass and colorectal cancer was performed in Stockholm in 1986-1988. The study included 1,081 subjects. The relative risks (RR, with a 95% confidence interval, highest versus lowest quintile) for colon cancer were as follows: total energy (1.7, 1.0-3.0), protein (2.4, 1.5-4.0), total fat (2.2, 1.3-3.6), dietary fiber for men (0.5, 0.2-1.1), dietary fiber for women (1.2, 0.7-2.3) and body mass (2.0, 1.3-3.1). The relative risks for rectal cancer were: total energy (2.4, 1.2-4.7), protein (3.6, 2.0-6.4), total fat (2.5, 1.4-4.6), dietary fiber (0.5, 0.3-0.9), body mass for men (1.7, 0.7-4.0), and body mass for women (1.0, 0.5-1.9). Adjustment for physical activity, body mass (in the diet analysis), the above-mentioned dietary factors (in the body mass analysis), and browned meat surface had little or no influence on the results.

Adult↗
PubMed1990

Vitamin A supplements, fried foods, fat and urothelial cancer. A case-referent study in Stockholm in 1985-87.

In a population-based case-referent study of urothelial cancer in Stockholm during 1985-87, information was obtained from 78% of 418 identified cases and 77% of 511 selected referents. The relative risk (with 95% confidence interval) for intake of vitamin A supplements was 0.5 (0.2-1.0), with a dose-response relationship with increasing frequency of consumption. Increased risks of urothelial cancer were seen for several fried foods, for example fried meat [relative risk 1.4 (1.0-1.8) for weekly intake] and fried potatoes [relative risk 1.6 (1.1-2.6) for weekly intake]. Subjects with a high intake of fried foods, as defined by a collapsed variable, had a relative risk of 2.4 (1.4-4.2). A dose-response relationship was also seen with an increasing average daily intake of fat [relative risk 1.7 (1.0-2.8) in the highest quintile], but adjusting for fried foods decreased the relative risk, and it is uncertain whether the adjustment allowed for residual confounding. No association was noted for meat other than fried, but the analysis was based on small numbers.

Carcinoma, Squamous Cell↗
PubMed1990

Increased risk of urothelial cancer in Stockholm during 1985-87 after exposure to benzene and exhausts.

In a population-based case-referent study of urothelial cancer in Stockholm during 1985-87, information was obtained from 80% of 320 identified male cases and 79% of 363 selected male referents. Industrial exposures were assessed for each subject by an industrial hygienist on the basis of questionnaire data. Exposure to benzene (any annual dose) gave a relative risk (with 95% confidence interval) of 2.0 (1.0-3.8). The highest risk was seen for a high annual dose. Subjects exposed to both diesel and petrol exhausts (moderate/high annual dose) had a relative risk of 7.1 (0.9-58.8). However, adjusting for benzene changed the relative risk to 5.1 (0.6-43.6). It might be rewarding to consider whether benzene from petrol confounds the associations previously suggested between exhausts and urothelial cancer. Exposure to polychlorinated biphenyls (PCB) gave a relative risk of 3.3 (0.6-18.4).

Benzene↗
PubMed1990

Urothelial cancer and some industry-related chemicals: an evaluation of the epidemiologic literature.

In a previous cohort study by our group, certain industry-related chemicals were judged as warranting further attention as possible urothelial carcinogens. In this paper, the epidemiologic literature of cancer of the lower urinary tract is evaluated for these substances. We would like to add combustion gases/soot from coal to the substances considered as increasing the risk of urothelial cancer. It is, however, uncertain whether this risk is due to contaminants of aromatic amines in tar volatiles or whether it depends on other agents, such as nitroarenes or polycyclic aromatic hydrocarbons. Furthermore, we find some support for the hypothesis that exposure to chlorinated aliphatic hydrocarbons increases the risk of urothelial cancer. For creosote, cutting fluids and cutting oils, hair dyes, and polychlorinated biphenyls, data are scarce. Available data do not support the hypothesis that asbestos is associated with urothelial cancer. "Publication bias," such that only limited information was available, was judged to be a potential problem in the review for many, but not all, of the substances investigated.

Case-Control Studies↗
PubMed1990

Colorectal cancer in Sweden. A descriptive epidemiologic study.

In a register-based 19-year follow-up we studied the incidence rate of colorectal cancer in the Swedish 1960 census population. A total of 53,377 cases were identified: 28,003 men and 25,374 women. A U-shaped distribution of tumors in the large bowel was observed, with a minimum in the descending colon. Other findings were 1) An incidence gap between elderly men and women increasing with age and with distal direction in the large bowel; 2) An increase in the incidence of colorectal cancer with population density; 3) A higher incidence of colorectal cancer in the southwestern region than in the northern region and 4) A lower incidence of colon cancer among blue than among white collar workers and a lower incidence of colorectal cancer among never married men than among other men.

Adult↗
PubMed1990

Recombinant leukocyte interferon alpha-2a and medroxyprogesterone in advanced renal cell carcinoma. A randomized trial.

In a randomized study of advanced renal cell carcinoma 60 patients were allocated to treatment with either recombinant interferon alpha-2a or medroxyprogesterone acetate. Correlation between the dose of interferon alpha-2a and plasma-concentration indicated linear kinetics. Survival was similar in the two treatment groups. Only one complete and one partial response were seen in the interferon group and only one complete response in the medroxyprogesterone group, indicating a low therapeutic potential of both interferon and medroxyprogesterone. Interferon influenced the serum liver enzyme levels; increased transaminases were seen in 17 patients treated with interferon but in only four patients in the medroxyprogesterone group. Two patients had very high serum liver-enzyme levels concomitant with intolerable tiredness, in both patients the symptoms disappeared and the enzymes normalized after discontinuation of the interferon treatment. Antibodies to interferon developed frequently in patients receiving high dose oligomeric interferon therapy but rarely in patients receiving low dose monomeric interferon treatment.

Adult↗
PubMed1989

Industry-related urothelial carcinogens: application of a job-exposure matrix to census data.

A job-exposure matrix has been developed linking the work tasks in the Swedish National Census of population 1960 to exposure to 50 single agents or groups of substances. All 1,905,660 men, aged 20-64 years in 1960, reporting themselves as gainfully employed in the Census, were observed for the occurrence of urothelial cancer 1961-1979 by linkage to the National Swedish Cancer Registry. Subjects classified as exposed to creosote had a relative risk (with 95% confidence interval) of 2.6 (1.2-5.9) for renal pelvis cancer and 1.3 (1.0-1.8) for urinary bladder cancer; subjects exposed to polychlorinated biphenyls (PCB) had a relative risk of 1.3 (1.0-1.8) for urinary bladder cancer. Adjustment was made for age, socioeconomic group, and degree of urbanization. Exposure to combustion gases from coal gave a relative risk of 1.2 (1.0-1.4) for bladder cancer. The study carries several sources of nondifferential misclassification diluting the estimates of the relative risks toward 1.0. The limitations of exposure classification by job-exposure matrices are discussed.

Adult↗
PubMed1988

Cancer in the respiratory organs of Swedish farmers.

In a cohort of 254,417 male Swedish farmers (4,330,717 person-years) the incidence of cancer of the respiratory organs was compared to a reference cohort of 1,725,845 men (30,131,664 person-years) employed in other economic activities than agriculture or forestry. In the study cohort 1450 cases of cancer in the respiratory organs were found in 1961 to 1979 resulting in an estimated relative risk (RR) of 0.38 (95% confidence interval [CI]: 0.36-0.40). For cancer of trachea, bronchus and lung, the decreased risk was equal for adenocarcinoma and squamous cell carcinoma. No time related trend in RR for any of the histologic subtypes could be seen. However, for squamous cell carcinoma in nose and nasal sinuses RR has increased from 0.42 (95% CI: 0.20-0.80) in 1961 to 1966 to 2.06 (95% CI: 1.22-3.50) in 1974 to 1979.

Adenocarcinoma↗
PubMed1988

Diet, tobacco and urothelial cancer. A 14-year follow-up of 16,477 subjects.

Urothelial cancer has been linked with tobacco, phenacetin-containing analgesics and some industrially-related carcinogens. Carotene has been suggested as reducing the risk of urothelial cancer but there is not much information on the relation between diet and the incidence of human urothelial cancer. Furthermore, the magnitude of the risk of urothelial cancer for pipe smokers remains unclear. In a 14-year follow-up of 16,477 Swedish twins the rate ratio of urothelial cancer (with 95% confidence interval) for subjects with a moderate/high intake of pork and beef respectively was 1.6 (1.0-2.7) and 1.6 (1.0-2.6). Meat consumption is widespread in Western populations. If the finding is supported by further data, a possible etiologic factor associated with the consumption of beef and pork would account for a substantial proportion of the cases of urothelial cancer. The rate ratio for men smoking a pipe/cigars, but not cigarettes, was 3.3 (95% confidence interval 1.5-7.4).

Cohort Studies↗