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Biomedical subjects

R Dewar

Publications and source records attributed to R Dewar.

48 records · Page 3Linked to original sources
PubMed1985

Factors influencing the survival of patients with cancer of the stomach.

During the period 1969 through 1973, 332 male and 135 female patients diagnosed with stomach cancer were registered with the Cross Cancer Institute in Edmonton, Alberta. These patients were followed up to December 31, 1981. Therefore, we were able to observe eight year survival times for all patients. Rates for one to eight years of survival were calculated using the Kaplan-Meier method. The results showed poor survival experience for male and female patients, similar to survival reported in other countries. Stomach cancer in Alberta belongs to the ten most common cancers and a search for factors influencing survival is therefore important. A large number of environmental factors and factors pertaining to the patients' lifestyle, as well as clinical factors related to stage of disease and treatment were examined using Cox's proportional hazard model. Surgical treatment and the presence of metastases were found to be important determinants of survival for both sexes. In males, increased age and British ethnicity were associated with poor survival prospects. Relative hazards of dying are presented for various combinations of factors.

Adult↗
PubMed1984

Nickel and cancer associations from a multicancer occupation exposure case-referent study: preliminary findings.

Since 1979 our group has been engaged in a case-referent study of 12 tumour types (oesophagus, stomach, colon, rectum, liver, pancreas, lung, melanoma of skin, prostate, bladder, kidney, lymphoid tissue) and occupational exposure. The study covers the entire Montreal population of males aged 35-70; cases are ascertained in all major hospitals. The interview concerns various sociodemographic variables and a detailed job history. Each job history is evaluated by a team of chemists who infer for each job what the possible physical and chemical exposures were. The list of exposures thus inferred is added to the subject's data file. Each site and each exposure noted in any patient's history are statistically evaluated for possible association. Until June 1982, 1 343 cancer cases and 144 general population subjects had been thus interviewed. For the present purpose, all 1 487 files were reviewed to assign exposure to nickel, and nickel exposure was attributed to 79 subjects. Mantel-Haenszel analyses were carried out comparing each site with a referent group consisting of all other interviewees (other sites and healthy controls). Only the nickel-lung association turned out to be remarkable, with an odds ratio of 3.1, 95% confidence limits 1.9-5.0, and some indication of dose-response effect. The risk was particularly high among stainless-steel welders, though other nickel-exposed workers were also at risk. These findings probably reflect a real risk; however, we cannot be certain that nickel is responsible. Exposure to chromium compounds was so highly correlated with nickel that the observed nickel association may simply have reflected a confounding effect of chromium. Confounding with other occupational exposures is also possible.

Adult↗
PubMed1982

Factors influencing the survival of patients with cancer of the prostate.

During the period 1969 through 1973, 777 new cases of cancer of the prostate in northern Alberta men were registered with the Alberta Cancer Registry. The overall survival rate after 5 years was 41.2%. As expected, the rates were higher for those aged less than 65 years than for those who were older at the time of diagnosis and higher for those without metastases than for those with metastases at that time. Urban residents had a higher survival rate than rural residents (45.3% v. 38.0%), and the survival ratio of the former, 1.31, was significant. Information on occupation, smoking and the interval between appearance of the first symptom and diagnosis was not always available. However, the differentials observed suggest that those in a professional occupation and nonsmokers live longer after the diagnosis of cancer of the prostate but that the interval before diagnosis does not affect the length of survival.

Aged↗
PubMed1980

Maternal post-delivery weight in the assessment of obesity.

Maternal weight recorded on the day after delivery correlated significantly with maternal skinfold thickness measured at multiple sites. Skinfold thickness probably reflects total body fat stores. It is suggested that the relationship between maternal weight and fetal birth weight may be mediated by the amount of maternal fat available to meet the energy requirements of the growing fetus.

Body Weight↗
PubMed1978

Size, technology, complexity, and structural differentiation: toward a theoretical synthesis.

This paper proposes a theoretical synthesis of the concepts of organizational size, technology, complexity, and structural differentiation. It suggests and finds that the most important determinant of differentiation in the division of labor is the scope of an organization's task, a technological dimension, and not organizational size. Neither horizontal nor vertical differentiation is thought to be determined by size while the scope of the task is proposed as a determinant of horizontal differentiation. The findings, however, support only the inference of a moderate causal connection between either size or task scope and either form of differentiation. Throughout the analysis and discussion the contrast between causal inference based on associations of levels and change rates is discussed. When dealing with the organizational processes addressed in this paper, both associations must be examined to adequately portray the complexity of the causal processes inferred.

Models, Theoretical↗
PubMedDate not supplied

Statistical methods for relating several exposure factors to several diseases in case-heterogeneity studies.

Statistical methods for characterizing risks are now well-developed, although little attention has focussed on the problem of risk identification, as in the surveillance of adverse drug reactions or occupational cancers. In this paper we consider the analysis of studies in which one ascertains and compares cases of several disease groups in terms of exposure histories. We address the problem of adjusting each risk for the confounding effects of all the other risks in the data. Data analysis consists of multidimensional contingency tables or polychotomous logistic regression. The latter approach focuses attention on the exposure-disease relations of primary interest rather than on those among the exposure factors and higher-order interactions, and applies easily to many exposure variables and to continuous exposure variables. We describe a stepwise approach to selecting effects for inclusion in the model. Application to preliminary data from a study aimed at identification of hitherto unsuspected occupational carcinogens illustrates the general approach.

Biometry↗
PubMedDate not supplied

Incidence of cancer in Sydney and Cape Breton County, Nova Scotia 1979-1997.

The primary purpose of this study was to assess whether Sydney, Industrial Cape Breton County excluding Sydney (ICBxS) and Cape Breton County (CBCo) residents were at increased risk for cancer compared to Nova Scotia (NS) residents over five-year periods during 1979 through 1997. Gender-stratified, age-standardized cancer incidence rates were calculated following the direct method. All-cause rates were higher for female and male residents of Sydney, ICBxS and CBCo compared to NS based upon both municipality and postal code methods of residence classification. A sensitivity analysis of residential coding yielded a high degree of consistency for all geographies except Sydney, limiting comparisons of Sydney rates with other local geographies except where consistencies were observed. The results of this ecological study support the need for further analysis of factors contributing to the increased risk for cancer in CBCo.

Age Distribution↗