Year: 2014
Type: letter
Abstract: We agree with the letter writer that tar content is an important element in lung cancer carcinogenesis and that “nicotine is addictive, but tar content is harmful” ( 1 ). However, we do not agree that “the observed association of TTFC [time to first cigarette] and lung cancer may be spurious” because there is “insufficient quantification of tar exposure by measures of smoking behavior” ( 1 ). Tar is harmful, but data on lung cancer mortality indicate that the relative and absolute risks of cigarette smoking and mortality from lung cancer are even stronger now than they were in the past, despite falling machine-measured tar yields ( 2 ). Clearly, machine-measured tar yields reflect only one aspect of cigarette carcinogenicity. For example, there is substantial evidence that cigarettes measuring as “low tar” induce compensatory behaviors that result in enhanced carcinogen delivery ( 3 ). Our report shows that TTFC contributes to lung cancer risk beyond the standard measures of duration and intensity (cigarettes per day) and cumulative exposure (pack-years) ( 4 ). Supporting our work on TTFC, previous data clearly demonstrate that TTFC is associated with cotinine ( 5 ), absorbed carcinogen dose ( 6 ) beyond cigarettes per day, depth of inhalation ( 4 ), and difficulty quitting ( 7 ); diverse and extensive lines of evidence establish that all of these aspects of cigarette smoking impact lung cancer risk. TTFC is useful because it provides additional lung cancer risk stratification beyond available smoking metrics and therefore offers a straightforward tool worthy of further evaluation. The letter writer suggests that a question on “tobacco blend” may be similarly informative ( 1 ). We welcome studies to test that speculation; however, as we mentioned, changing cigarette designs to “low tar” cigarettes did not reduce mortality from lung cancer or other diseases among smokers, perhaps hindering prevention and cessation ( 8 ). The labeling of tar content was prohibited by the Family Smoking Prevention and Tobacco Control Act passed in 2009 ( http://www.fda.gov/tobaccoproducts/guidancecomplianceregulatoryinformation/ucm214597.htm ) to avoid such a potentially misleading assumption. Since brands and constituents change over time, we are skeptical that information on “tobacco blend” would add additional information about risk. Nor would such an effort match the simplicity of administration, ease of interpretation, or magnitude of risk explained by TTFC.
DOI: 10.1093/jnci/dju350
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4245227169