Can We Trust National Smoking Prevalence Figures? Discrepancies Between Biochemically Assessed and Self-Reported Smoking Rates in Three Countries
- 1Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, London, United Kingdom and 2Cancer Epidemiology and Prevention Division, The Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
- Requests for reprints:
Robert West, Epidemiology and Public Health, University College London, Torrington Place, London, United Kingdom. Phone: 44-2076796633. E-mail: robert.west{at}ucl.ac.uk
Abstract
Background: National smoking prevalence estimates are the primary basis for assessing progress in tobacco control across the world. They are based on surveys of self-reported cigarette smoking. It has been assumed that this is sufficiently accurate for policy purposes, but this assumption has not been adequately tested.
Methods: We report data from the 2003 Health Survey for England, the U.S. National Health and Nutrition Examination Survey for 2001-2002, and the 2004 national smoking behaviors survey in Poland as examples of countries at different stages in the “tobacco epidemic.” Self-reported cigarette and total tobacco smoking prevalence were assessed by means of the standard questions used in each country. In subsamples, specimens were collected for analysis of cotinine (saliva, N = 1,613 in England; serum, N = 4,687 in the United States; and saliva, N = 388 in Poland) providing an objective means of determining active smoking. A cut point of 15 ng/mL was used to discriminate active smoking from passive smoke exposure.
Results: Self-reported cigarette smoking prevalence using the standard methods underestimated true tobacco smoking prevalence by an estimated 2.8% in England, 0.6% in the United States, and 4.4% in Poland. Cotinine concentrations in those misclassified as nonsmokers were indicative of high levels of smoke intake.
Interpretation: Underestimation of smoking prevalence was minimal in the United States but significant in England and Poland. A review of methodologies for assessing tobacco smoking prevalence worldwide is urgently needed. (Cancer Epidemiol Biomarkers Prev 2007;16(4):820–2)
Footnotes
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↵3 Full details of the methodology are available online at www.archive2.official-documents.co.uk/document/deps/doh/survey03/hse03.htmin.
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↵4 Unpublished data from the Institute of Market Research.
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Grant support: Cancer Research United Kingdom. The Polish contribution was supported by the Closing the Gap Project, funded by the European Union Directorate for Health and Consumer Protection (Action 2003121).
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The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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Note: Robert West devised the study, contributed to the statistical analysis, and led the process of drafting the manuscript. Witold Zatonski helped devise the study, led the team collecting the Polish data, and contributed to the drafting of the manuscript. Krzysztof Przewozniak supervised the Polish data collection and helped with the statistical analysis and with the drafting of the manuscript. Martin Jarvis helped devise the study and contributed to the statistical analysis and the drafting of the manuscript.
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Conflicts of interest: Robert West has undertaken research and consultancy for companies that develop and manufacture smoking cessation medications. He also has a share of a patent on a novel nicotine inhalation device. Witold Zatonski and Krzysztof Przewozniak have no conflicts of interest. Martin Jarvis has undertaken research and consultancy for companies that develop and manufacture smoking cessation medications.
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Disclaimer: Health Survey for England data were made available through the United Kingdom Data Archive. Public release data files for the National Health and Nutrition Examination Survey were made available through the U.S. National Center for Health Statistics.
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- Accepted January 18, 2007.
- Received August 10, 2006.
- Revision received December 14, 2006.
