New Haven, Conn.--New research from the Yale School of Public Health reveals that differences in smoking habits between African Americans and whites may lead to a disparity in screening for lung cancer.

The paper was published online March 15 in Nicotine & Tobacco Research.

Cigarette smoking, the leading cause of preventable death in the United States, has been widely studied, yet most studies have focused on how the habit affects the population as a whole. Attention to smoking patterns within specific racial and ethnic groups has been limited.

For the study, Theodore Holford, the Susan Dwight Bliss Professor of Public Health (biostatistics), and colleagues used data from the National Health Interview Surveys, conducted from 1965 to 2012, to pinpoint differences in tobacco-smoking habits between African Americans and white smokers. The researchers analyzed the changes in smoking behavior that occurred after the publication of the landmark U.S. Surgeon General's Report on Smoking and Health in 1964, which was the first federal report to link smoking with adverse health effects and spurred a nationwide effort to curb tobacco use.

"Racial differences in smoking initiation, cessation, and intensity give rise to substantial differences in risk for tobacco-related diseases," said Holford, who is also a member of Yale Cancer Center's Cancer Prevention and Control Program. "Further research is needed to quantify these effects for specific diseases, but this study shows that commonly used measures may give rise to disparities in access to lifesaving interventions."

Holford found that while African Americans are less likely than whites to start smoking in their late teen years -- when most smoking habits start -- they are also less likely than whites to quit as they get older. In addition, African Americans who smoke report using fewer cigarettes per day.

These differences result in important and somewhat contradictory differences in lifetime exposure, note the researchers. While white smokers tend to begin when they are younger, African Americans tend to continue smoking into their later years, resulting in longer average duration of exposure when the effects of tobacco-related disease become more apparent.

Yet lower smoking intensity gives rise to African Americans having fewer average "pack-years" -- calculated by multiplying the number of packs smoked per day by years of smoking -- which is a criterion used to determine eligibility for lung cancer screening. By this criterion, fewer at-risk African Americans are eligible for screening. This is problematic, said the researchers, because their risk of death from tobacco-related diseases is as high or higher than that of their white counterparts.

The results of this study, Holford said, will be useful in better understanding racial disparities in several tobacco-related diseases, which in addition to lung cancer, include heart disease and chronic obstructive pulmonary disease.

The results also underscore the need to consider variations in smoking habits among racial groups in developing healthcare policy, in particular lung cancer screening eligibility, said the researchers. Current guidelines that make no distinction among different subsets of the population may not be the most effective use of efforts to control death from tobacco-related diseases like lung cancer, Holford said, noting that additional studies are needed to determine whether a sufficient number of African Americans are screened under current guidelines or if changes to current policy are necessary.

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Holford co-authored the paper with researchers from Cancer Control Department of Oncology at Georgetown University, and the Department of Epidemiology at the University of Michigan School of Public Health.