Tobacco specific nitrosamines and potential reduced exposure products for smokers: a preliminary evaluation of Advance(TM)

The causal relation between tobacco smoking and a variety of cancers (for example, lung, larynx, pancreas, bladder, etc) is well documented ¹ and is attributable to the many carcinogens that smokers inhale, including tobacco specific nitrosamines (TSNs). ² The best method for smokers to avoid these tobacco delivered carcinogens is to quit smoking. However, most smokers find quitting difficult because they are dependent upon cigarette delivered nicotine. ³ As an alternative, the tobacco industry markets potential reduced exposure products (PREPs) that purport to reduce smokers' tobacco delivered carcinogen exposure (for example, RJ Reynolds' Eclipse^(TM) , Brown and Williamson's Advance(TM)). ^{4, 5} Careful evaluation of these and other PREPs is essential, ^{5, 6} given that previous industry sponsored PREPs (that is, low yield cigarettes) reduced neither smokers' exposure to tobacco delivered toxicants nor tobacco associated mortality. ⁷

PREP evaluation will likely be complex, involving the combined efforts of basic, epidemiological, and clinical researchers. Basic research studies can reveal carcinogen concentrations within tobacco and/or tobacco smoke, though they do not model the variability of human smoking behaviour. ^{7, 8} Epidemiological studies can reveal the extent to which PREPs increase or decrease the risks of tobacco use, ⁷ though data can take years to accumulate. Short term clinical studies are efficient and valuable, and can reveal PREP effects on tobacco use parameters (for example, puff volume or number), withdrawal symptomatology, and exposure to carbon monoxide (CO) and nicotine. ^{4, 5} However, some biomarkers for tobacco carcinogen exposure have long half lives, ⁹ requiring longer term clinical studies to assess PREP induced changes in carcinogen exposure. ^{4- 6}

Advance(TM) is a PREP marketed as a means to reduce exposure to tobacco toxicants, including TSNs. ¹⁰ According to the manufacturer, "a patented tobacco curing process significantly inhibits the formation of tobacco-specific nitrosamines" in the tobacco used to make this PREP. ¹⁰ No epidemiological data are available regarding Advance(TM). In a short term clinical study, Advance(TM) produced equivalent withdrawal suppression and tachycardia, 11% lower CO, and a 25% increase in plasma nicotine, relative to own brand cigarettes. ⁴ TSN exposure was not examined, because smokers only used Advance(TM) in a single, 2.5 hour session. Longer evaluations will be required to characterise PREP induced changes in TSN exposure. For example,...