PubMed Health⌕ Search

Biomedical subjects

G J Macfarlane

Publications and source records attributed to G J Macfarlane.

96 records · Page 6Linked to original sources

Analysis of quantitative data by quantiles in epidemiologic studies: classification according to cases, noncases, or all subjects?

Quantitative exposure data in epidemiologic studies are frequently analyzed by ordered categories. Categorization by quantiles can be based on the distribution of (1) cases, (2) noncases, and (3) all subjects. The advantages of the three schemes in determining quantiles were compared. They were found to give the same power regarding a test for trend over a wide range of study situations. Considerations on the representativeness and the ease of the analysis implementation could dictate the choice of the categorization scheme.

Case-Control Studies↗

Epidemiology of mouth cancer in 1989: a review.

The oral cavity and pharynx combined is the sixth commonest site of cancer in both sexes. In many countries the mortality rate is increasing among younger men born since approximately 1910-1920. A causal role in the aetiology of mouth cancer has been established for tobacco use, both smoking and chewing, separately and in conjunction with betel-quid chewing; with alcohol consumption and, less certainly, with other factors such as poor oral hygiene, nutritional factors and certain occupational exposures. In Western countries, there is convincing evidence that a large attributable risk can be ascribed to the joint habits of cigarette smoking and alcohol consumption. In Asian societies, a high attributable risk can be ascribed to cigarette smoking and betel chewing. Mouth cancer is at the same time an important form of cancer, and one for which practical prospects for prevention already exist. Against this background of a continually increasing trend among younger persons, it seems essential to engage upon programmes of prevention, including increasing awareness for early detection, against mouth cancer at the present time.

Areca↗

Epidemiology of pancreas cancer (1988).

This article reviews the epidemiology of cancer of the pancreas, both descriptive and analytical, at all times cognizant of the problems of misdiagnosis, particularly underdiagnosis, of this lethal disease that continue to hinder epidemiological studies. Pancreas cancer is consistently reported to occur more frequently in men than in women, in blacks than in whites, and in urban rather than rural population groups. In some countries, the mortality rates continue to rise, whereas in others, declining levels of disease can be seen among members of younger birth cohorts. Although some of these patterns can be explained by variation in pancreas cancer risk factors, many cannot. Analytical studies consistently demonstrate that cigarette smoking increases the risk of cancer of the pancreas, and this appears, at the present time, to be the only clearly demonstrated risk factor for pancreatic cancer. Although the association with disease risk and coffee consumption, alcohol consumption, occupational exposures, diabetes, pancreatitis, and other factors requires clarification, it appears likely that the most fruitful research area in the coming years may involve exploration of pancreatic cancer risk and nutritional practices.

Adult↗

Risk factors and prognosis in primary biliary cirrhosis.

The relationship between survival and 25 clinical and histologic variables was studied in 195 patients (171 women, 24 men) who satisfied stringent criteria for the diagnosis of primary biliary cirrhosis. The mean duration of follow-up was 6 yr (range 0-17). One hundred and sixteen patients died, 84% as the result of liver disease and 16% from nonhepatic causes. Using the Kaplan-Meier estimate, we calculated the mortality from liver disease to be 40% after 5 yr and 60% after 10 yr. Ascites, serum bilirubin level, variceal hemorrhage, and age were identified as independent clinical risk factors, and extent of hepatic fibrosis, bilirubinostasis, and Mallory's hyalin were identified as independent histologic risk factors correlating with reduced survival.

Adult↗