Despite advances in knowledge concerning risk factor reduction and improvements in early detection and treatment for several cancers, socioeconomic inequalities in cancer mortality persist, and in some instances, such inequalities (including those for screenable cancers) may even be widening. Socioeconomic differences in cancer mortality may reflect differences in lifestyle factors such as smoking, diet, obesity, and physical activity and differences in environmental pollutants and contaminants as well as differences in preventive health care practices and access to and use of medical care. A full understanding of the extent and causes of such social inequalities is crucial to the development and implementation of a comprehensive and effective national strategy for cancer control and prevention and improved survival and quality of life for cancer patients.The national vital statistics mortality data, compiled and maintained by the National Center for Health Statistics (NCHS), are based on information from death certificates of every death occurring in the United States each year, and are the only source for computing annual cancer mortality statistics for the entire nation and for all states and counties. To compute death certificate-based cancer mortality rates, age-sex-race- and geographic area-specific population denominator data representing the population at risk are drawn from another source the decennial census and intercensal population estimates maintained by the U.S. Bureau of the Census. Because of inconsistencies in the reporting of social and demographic characteristics in the two data systems, the estimates of mortality rates by such variables as race/ethnicity, education, marital status, educational attainment, and occupation may be biased. Moreover, there are only limited number of social and demographic characteristics available on the death certificate, which include age, sex, race/ethnicity, marital status, and place of birth and residence, educational attainment, usual occupation and industry. Data on ethnicity, educational attainment, and occupation remain rather suspect, and information on income, a key indicator of the individual socioeconomic position, is not collected on the death certificate. Data on health status, co-morbidity, as well as health-risk behaviors such as smoking for individual decedents are also absent. Consequently, socioeconomic analyses of cancer mortality generally rely on aggregate ecological data where area-specific cancer mortality rates are modeled as a function of census-based aggregate socioeconomic and demographic characteristics for the corresponding geographic areas.
