Preliminary report of an exposure-based, case-control monitoring system for discovering occupational carcinogens.

There is no evidence concerning human carcinogenic potential of most substances to which workers are exposed. A case-control type method has been developed to discover heretofore unsuspected occupational carcinogens. Incident cases of cancer of several sites are ascertained and the subjects are interviewed to obtain detailed job histories.

Biological models and statistical interactions: an example from multistage carcinogenesis.

From the assessment of statistical interaction between risk factors it is tempting to infer the nature of the biologic interaction between the factors. However, the use of statistical analyses of epidemiologic data to infer biologic processes can be misleading. as an example, we consider the multistage model of carcinogenesis.

Equality in medical care under national health insurance in Montreal.

In November 1974, four years after national health insurance in Canada had eliminated all out-of-pocket payment for physicians' services, we surveyed 1559 households in a socially heterogeneous area of Montreal to assess social-class differences in the use of physicians' services. When reported health status as well as age and sex were taken into account, the rates of physician visits during the two-week period preceding the survey were essentially the same in the low, middle, and high economic classes, thus confirming that disparity of access had been reduced. However, relative to other groups, the poor still made considerable use of hospital clinics and emergency rooms for primary care and more of their visits entailed prescriptions and physician-initiated requests to return.

Space-time clustering of Burkitt's lymphoma in East Africa: analysis of recent data and a new look at old data.

Forty cases of Burkitts' lymphoma (BL) in North Mara, Tanzania, with onset between 1971 and 1977, were analysed for evidence of space-time clustering. Previous analyses in East Africa had produced conflicting results. The Knox method used in those analyses dichotomizes the space and time scales and does not take into account the degree of closeness.

A comparison of mail, telephone, and home interview strategies for household health surveys.

The method of data collection in household health surveys can be a major determinant of cost and data quality. A survey strategy can comprise mail, telephone, or home interview methods, individually or in combination to follow up non-respondents. The purpose of this study in Montreal was to compare cost and data quality of various strategies.