Tobacco dependence in light smokers

I wish to commend Reitzel et al. (2009) for their excellent study concerning low-level smoking among Spanish-speaking Latino smokers but would like to challenge their interpretation of the data. The authors compared low-level smokers (1–5 cigarettes/day) with light smokers (6–10 cigarettes/day) and heavy smokers (>10 cigarettes/day). They found (a) that low-level smokers had measurable dependence on all 13 subscales of the Wisconsin Inventory of Smoking Dependence Motives; (b) that “smoking level was strongly associated with craving, F(2, 221) = 6.19, p = .0024, but not with other withdrawal symptoms”; (c) that three quarters of the low-level smokers relapsed during a smoking cessation trial; and (d) that the relapse rate among low-level smokers was statistically indistinguishable from that for the heaviest smokers. Quizzically, they conclude that these data support the contentions that individuals who smoke fewer than 5 cigarettes/day do not smoke “in response to physiological withdrawal symptoms,” do not experience nicotine withdrawal, and have little to no dependence. As I see it, the data show the opposite: Low-level smokers had all manner of dependence symptoms and, with the exception of craving, experienced withdrawal equivalent to heavy smokers. How can one conclude that low-level smokers have no dependence when three quarters of them could not maintain abstinence for 12 weeks under a professional treatment program? To the contrary, the Reitzel et al. (2009) article is consistent with more than a dozen recent studies that clearly demonstrate that low-level smokers experience nicotine withdrawal and all other aspects of nicotine dependence (Caraballo, Novak, & Asman, 2009; Dierker et al., 2007; Kandel, Hu, Grieisler, & Schaffran, 2007; O’Loughlin et al., 2003; Savageau, Mowery, & DiFranza, 2009; Scragg, Wellman, Laugesen, & DiFranza, 2008).