Oral cancer in a tobacco-chewing US population--no apparent increased incidence or mortality

Smokeless tobacco use is an accepted risk factor for oral cancer in the United States, but the major proof of this is based largely on a single epidemiologic (case-control) comparison of women, whereas the chewing of tobacco is predominantly a habit of men. The present investigation sought to compare gender-specific oral cancer mortality and incidence rates in West Virginia, the state with the highest per capita consumption of smokeless tobacco, with rates from other states and with the US average rates. It was hypothesized that the cancer rates for West Virginia males would be significantly greater than the US average and greater than the rates for states with less smokeless tobacco consumption.

Data from the West Virginia Cancer Registry for the years 1993 through 1995 were compared with data from contemporary Surveillance and Epidemiology End Results for the US (with respect to incidence) and from the Center for Disease Control and Prevention's National Center for Health Statistics (with respect to mortality).

The average annual incidence rates (per 100,000 population) for oral/pharyngeal cancer in West Virginia males and females were 13.4 and 5.1, respectively; these compared with rates of 15.4 and 5.7 for the US. The average annual mortality rates (per 100,000 population) for the disease in West Virginia males and females were 4.2 and 1.6, respectively; these compared with 4.4 and 1.5 for the US. West Virginia oral/pharyngeal mortality rates for both genders were statistically significantly lower than US rates throughout the years 1950 through 1980. Among other potential oral cancer etiologic factors, the very low prevalence of alcohol abuse in West Virginia seemed to be relevant.

The hypothesis was not confirmed by data analysis. West Virginia is the state with the highest per capita consumption of smokeless tobacco, yet it has less oral/pharyngeal cancer than the US average. The authors strongly urge additional and improved epidemiologic evaluation of the oral cancer risk of smokeless tobacco use in US males.