Deane W. Merrill

Distance and risk measures for the analysis of spatial data: a study of childhood cancers.

Three statistical approaches, used to detect spatial clusters of disease associated with a point source exposure, are applied to childhood cancer data for the city of San Francisco (1973-88). The distributions of incident cases of leukemia (51 cases), brain cancer (35 cases), and lymphatic cancer (37 cases) among individuals less than 21 years of age are described using three measures of clustering: distance on a geopolitical map, distance on a density equalized transformed map, and relative risk. The point source of exposure investigated is a large microwave tower located southwest of the center of the city (Sutro Tower). The three analytic approaches indicate that the patterns of the major childhood cancers are essentially random with respect to the point source. These results and a statistical model for spatial clustering are used to explore distance and risk measures in the analysis of spatial data. Both types of measures of spatial clustering are shown to perform similarly when a specific area of exposure can be defined.

Transformations of Maps to Investigate Clusters of Disease

An approach is presented to display and analyze epidemiologic data using population density equalized maps (cartograms). The algorithm for generating these maps is discussed. A specific method for statistically analyzing plotted data is given, followed by an application of maps and analysis to 73 sets of age-, race-, sex-, and site-specific cancer incidence data. The data were obtained from the Surveillance, Epidemiology and End Results project for San Francisco City/County (1978-1981) and combined with 1980 U.S. Census data.

A study of multiple causes of death in California: 1955 and 1980

Multiple cause of death patterns in California for 1980 were compared to a similar study of deaths conducted in 1955. Primary underlying causes of death changed, mainly reflecting the emergence of respiratory cancer as a major cause of death in 1980. The number of causes reported per death increased from 1955 to 1980, in all age and sex groups. Diseases of the arteries and pneumonia, which are among the most common underlying causes of death, appeared more often on death certificates in both 1955 and 1980 as contributing causes than as underlying the death. Diabetes was studied in detail in the 1955 report, and comparisons were made in 1980 to show increases in the proportions of deaths with this disease and corresponding increases in its prevalence among the living population from the National Health Survey. Multiple cause of death data can provide further information on the prevalence of a fatal disease in a population and its relative role in contributing to mortality, and can also provide new information on diseases that contribute to deaths, which was not previously available in population-based studies of single cause of death.