Lung Cancer Incidence in Nonmetropolitan and Metropolitan Counties - United States, 2007-2016

Our plain-English summary of Lung Cancer Incidence in Nonmetropolitan and Metropolitan Counties - United States, 2007-2016, by M.E. O'Neil, S.J. Henley, E.A. Rohan, et al (MMWR. Morbidity and Mortality Weekly Report, 2019).

The study

• Authors: M.E. O'Neil, S.J. Henley, E.A. Rohan, T.D. Ellington, M.S. Gallaway
• Journal: MMWR. Morbidity and Mortality Weekly Report
• Published: 2019;68(44):993-998
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Lung and bronchus (lung) cancer is the leading cause of cancer death in the United States (1). In 2016, 148,869 lung cancer deaths were reported.* Most lung cancers can be attributed to modifiable exposures, such as tobacco use, secondhand smoke, radon, and asbestos (1). Exposure to lung cancer risk factors vary over time and by characteristics such as sex, age, and nonmetropolitan or metropolitan residence that might affect lung cancer rates (1,2). A recent report found that lung cancer incidence rates were higher and decreased more slowly in nonmetropolitan counties than in metropolitan counties (3). To examine whether lung cancer incidence trends among nonmetropolitan and metropolitan counties differed by age and sex, CDC analyzed data from U.S. Cancer Statistics during 2007-2016, the most recent years for which data are available. During the 10-year study period, lung cancer incidence rates were stable among females aged <35, 45-64, and ≥75 years in nonmetropolitan counties, were stable among females aged <35 years in metropolitan counties, and decreased in all other groups. Overall, among males, lung cancer incidence rates decreased from 99 to 82 per 100,000 in nonmetropolitan areas and from 83 to 63 in metropolitan areas; among females, lung cancer incidence rates decreased from 61 to 58 in nonmetropolitan areas and from 57 to 50 in metropolitan areas. A comprehensive approach to lung cancer prevention and control includes such population-based strategies as screening for tobacco dependence, promoting tobacco cessation, implementing comprehensive smoke-free laws, testing all homes for radon and using proven methods to lower high radon levels, and reducing exposure to lung carcinogens such as asbestos (1). Increasing the implementation of these strategies, particularly among persons living in nonmetropolitan counties, might help to reduce disparities in the decline of lung cancer incidence.

In plain English

This CDC report analyzed U.S. Cancer Statistics registry data on new lung cancer cases diagnosed from 2007 to 2016. The data covered about 97% of the U.S. population, because county data for Kansas and Minnesota were not available. The authors compared age-adjusted incidence rates in nonmetropolitan and metropolitan counties by sex and age. The report did not measure asbestos exposure. Among males, rates fell from 99 to 82 per 100,000 in nonmetropolitan counties and from 83 to 63 in metropolitan counties. Among females, rates fell from 61.2 to 57.9 in nonmetropolitan counties and from 57 to 50 in metropolitan counties. Yearly declines were larger in metropolitan areas (males 2.9%, females 1.5%) than in nonmetropolitan areas (males 2.1%, females 0.5%). Rates were stable among nonmetropolitan females aged under 35, 45 to 64, and 75 and older, and among metropolitan females under 35. The authors noted that reporting delays might underestimate incidence. They concluded that rural-urban disparities persisted, and that wider use of proven prevention strategies, particularly among women in nonmetropolitan areas, might prevent lung cancer and decrease disparities.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Analysis of national population-based cancer registry data (incidence trends, 2007 to 2016)
• Who was studied: New invasive lung cancer cases diagnosed in the United States, 2007 to 2016, from registries covering about 97% of the U.S. population. Kansas and Minnesota were excluded because county-level data were unavailable.
• Exposure: County of residence at diagnosis: nonmetropolitan (USDA rural-urban continuum codes 4 to 9) versus metropolitan (codes 1 to 3), examined by sex and age group. Asbestos exposure was not measured; it is mentioned only as a known lung cancer risk factor.
• Main results:
  • Among males, lung cancer incidence fell from 99 to 82 per 100,000 in nonmetropolitan areas and from 83 to 63 per 100,000 in metropolitan areas.
  • Among females in metropolitan areas, incidence fell from 57 to 50 per 100,000.
  • Among females in nonmetropolitan counties, the age-adjusted rate was 61.2 per 100,000 in 2007 and 57.9 per 100,000 (95% CI 57.1 to 58.8) in 2016.
  • Annual declines were larger in metropolitan areas (males minus 2.9%, females minus 1.5%) than in nonmetropolitan areas (males minus 2.1%, females minus 0.5%).
  • Rates were stable (no statistically significant change) among nonmetropolitan females aged under 35, 45 to 64, and 75 and older, and among metropolitan females under 35. Rates decreased in all other groups.
  • In 2007, the rate among nonmetropolitan males (99 per 100,000) was 60% higher than among nonmetropolitan females (61 per 100,000).
  • In 2016, among persons aged 35 to 54, rates did not differ by sex but were higher in nonmetropolitan than in metropolitan counties.
  • In 2016, rates among women aged 35 to 64 in nonmetropolitan counties were higher than among men in metropolitan counties.
  • Differences between males and females narrowed with decreasing age, but rural-urban disparities persisted.
• The authors' conclusion: The authors concluded that accelerating proven strategies to reduce exposure to lung cancer risk factors, particularly among females in nonmetropolitan areas, might prevent lung cancer and decrease disparities.
• Limitations the authors state:
  • Delays in cancer reporting might lead to underestimated incidence.
  • The results might not apply to states excluded from the analysis.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Bronchus, Incidence.

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