Geographic Patterns in U.S. Lung Cancer Mortality and Cigarette Smoking

Abstract

Background: Despite the success of smoking cessation campaigns, lung cancer remains the leading cause of cancer death in the United States. Variations in smoking behavior and lung cancer mortality are evident by sex and region. Methods: Applying geospatial methods to lung cancer mortality data from the National Vital Statistics System and county-level estimates of smoking prevalences from the National Cancer Institute’s Small Area Estimates of Cancer-Related Measures, we evaluated patterns in lung cancer mortality rates (2005-2018) in relation to patterns in ever cigarette smoking prevalences (1997-2003). Results: Overall, ever smoking spatial patterns were generally associated with lung cancer mortality rates, which were elevated in the Appalachian region and lower in the West for both sexes. However, we also observed geographic variation in mortality rates that is not explained by smoking. Using Lee’s L statistic for assessing bivariate spatial association, we identified counties where the ever smoking prevalence was low and lung cancer rates were high. We observed a significant cluster of counties (n=25; p-values ranging from 0.001 to 0.04) with low ever smoking prevalence and high mortality rates among females around the Mississippi River region south of St. Louis, Missouri and a similar and smaller cluster among males in Western Mississippi (n=12; p-values ranging from 0.002 to 0.03) that has not been previously described. Conclusions: Our analyses identified U.S. counties where factors other than smoking may be driving lung cancer mortality Impact: These novel findings highlight areas where investigation of environmental and other risk factors for lung cancer is needed.

Cancer Epidemiology in the Northeastern United States (2013–2017)

“…Substantial proportions of the NNE population are exposed to arsenic through well water ( 78 ), as a large proportion of residents in NNE use private wells as their drinking water supply, and the high prevalence of arsenic and nitrates in the tri-state area is thought to contribute to high bladder cancer rates ( 8, 10, 81, 82 ). In addition to the burden of lung cancer due to smoking—with sex-specific differences that may drive some of the trends we report ( 77 )—it was estimated in 2003 that unmitigated radon in homes throughout the United States accounted for more than 21,100, or 13.4% of lung cancers each year ( 83 ). An estimated 1 in 15 (7%) homes in the United States exceed the EPA action level of 4pCi/L for indoor air, but the figures are much higher in VT (22%), NH (35%), and ME (37%; refs.…”

“…Compared with the United States, NNE has a relatively good record for cancer screening, overweight/obesity, exercise, and nutrition, but somewhat worse for smoking history and alcohol use. The higher incidence of lung/bronchus, esophagus, and bladder cancer could be in part attributable to this region's higher proportion of people who have ever smoked, because past smoking influences cancer risk after a corresponding latency period; it has been reported previously that rural areas have higher incidence of tobacco-related cancers than urban areas ( 88 ), and associations have been identified in this area between county-level ever smoking and lung cancer mortality ( 77 ) in women. Although NNE has a higher prevalence of heavy drinking than the United States, this is not consistently reflected in all of the alcohol-related cancers ( 89 ); NNE has higher incidence than the United States of breast, esophageal, and oral cavity/pharyngeal cancers, but lower or comparable incidence of colorectal, liver, and laryngeal cancers.…”

“…Many different cancer risk factors in this rural, tri-state environment may contribute to some of these patterns of incidence and mortality, including smoking ( 77 ), arsenic in well water ( 78 ), radon in air ( 79 ), and pollution; both NH and VT have more than three times the number of NPL sites (past, current, and proposed) per square mile than the United States average ( 34–36 ), as well as specific issues with contaminants such as perfluoralkyl substances ( 11, 80 ). Substantial proportions of the NNE population are exposed to arsenic through well water ( 78 ), as a large proportion of residents in NNE use private wells as their drinking water supply, and the high prevalence of arsenic and nitrates in the tri-state area is thought to contribute to high bladder cancer rates ( 8, 10, 81, 82 ).…”