Pollution and Regional Variations of Lung Cancer Mortality in the United States

Authors:

Justin Moore (Presenter)
University of Alabama at Birmingham

Tomi Akinyemiju, University of Alabama at Birmingham
Henry Wang, University of Alabama at Birmingham

Public Health Statement: In the United States (U.S.), cancer is the second leading cause of death responsible for more than 550,000 deaths annually. Among specific cancers, lung cancer is the leading cause of cancer deaths for both men and women. Ambient particulate matter pollution was recently classified as a Group 1 carcinogen to human populations. To date, few studies have examined regional trends in lung cancer mortality and/or prevalence using geospatial epidemiologic methodology, and whether particulate matter exposure are higher in these areas.

Purpose: The aims of this study were to identify United States (U.S.) counties with high lung cancer mortality, and to characterize the community-level factors associated with lung cancer mortality focusing on particulate matter pollution.

Methods/Approach: We performed a descriptive analysis of lung cancer deaths in the U.S. from years 2004 through 2014. For each U.S. county we identified deaths associated with the lung and bronchus from the Compressed Mortality File (CMF) that is derived from death certificates of all U.S. citizens and classified according to the International Classification of Diseases, 10^th Version. County-level particulate matter data were obtained from CDC WONDER, years 2003–2011. We categorized counties as ‘clustered’ or ‘non-clustered’ based on having high lung cancer mortality rates using novel geospatial autocorrelation methods. We contrasted community characteristics between cluster categories. We performed logistic regression for the association between cluster category and particulate matter pollution.

Results: Among 362 counties (11.6%) categorized as clustered, the age-adjusted lung cancer mortality rate was 99.70 deaths per 100,000 (95% CI: 99.1–100.3) compared with 75.6 deaths per 100,000 (95% CI: 75.4–75.7) persons in non-clustered counties. Compared with non-clustered counties, clustered counties were more likely in southern (72.9% vs. 42.1%, p <0.01) and non-urban communities (73.2% vs. 57.4, p<0.01). Clustered counties had higher particulate matter pollution, lower education and income, higher rates of obesity and physical inactivity, less access to healthcare, and greater unemployment rates (p < 0.01). Higher particulate matter (4^th quartile vs. 1^st quartile) was associated with 2-fold greater odds of being a clustered county (adjusted OR: 2.10; 95% CI: 1.23–3.59).

Conclusions/Implications: We observed a belt of high lung mortality counties ranging from eastern Oklahoma through central Appalachia, characterized by higher pollution, a more rural population, and lower SES and access to healthcare.