Table 1.

Various definitions of light smokers (generally categorized by number of cigarettes smoked per day; CPD)

	Light smoker		Very light smoker		Low-rate, low-level, low-rate daily, low-level daily smoker		Chippera
Maximum number of CPD	Definition	Study	Definition	Study	Definition	Study	Definition	Study
4, 5, or 6			<5	Shiffman et al. (1992)	<5	Zhu et al. (2003)	<5	Presson et al. (2002)
	1–4	Bjartveit & Tverdal (2005)	1–4	Rosengren et al. (1992)
	≤6	Janson (1999)	≤5 or <6	Hajek et al. (1995), Shiffman (1989)	≤5	Kenford et al. (2005), Owen et al. (1995)	≤5	Brauer et al. (1996), Gilpin et al. (1997), Wellman et al. (2006)
							Average ≤5	Shiffman (1989), Shiffman et al. (1990, 1992), Shiffman, Kassel, et al. (1994), Shiffman, Paty, et al. (1994)
					1–5	Etter (2004)	Average 1–5	Kassel et al. (1994), Sayette et al. (2001)
9 or 10	<10	Okuyemi et al. (2001)
	1–9	Biener & Albers (2004), USDHHS (1989)
	≤10 or <11	Costello et al. (2007), Okuyemi, harris, et al. (2002)			≤10	Arcavi et al. (1994)
	1–10	Choi et al. (2004), Okuyemi, richter, et al. (2002, 2004)
14 or 15	<15	CDC (1994), Falba et al. (2004), Hatsukami et al. (2006)a, Wilson et al. (1999)			<15	Hatsukami et al. (2006)a
	1–14	Borland et al. (1990), Godtfredsen et al. (2005, 2006)
	≤15	Killen et al. (1988), Shiffman (2005)
	5–14	Rosengren et al. (1992)
20	≤20	Cohen et al. (1989)			1–20	Mucha et al. (2006)
	10–20	Shiffman (1989)
					Nondaily, no more than 1 pack/week	Dierker et al. (2007)
Other	1–39 cigarettes/week	Dwyer et al. (1988)
					Average ≤5 CPD	Hyland et al. (2005)
					Group averaged <10 CPD	Zvolensky et al. (2007)
	≤3–5 g tobacco/day	Prescott et al. (2002)
	Never regularly, none in past 30 days	Stanton et al. (2007)
	Considered self a light smoker	Morley et al. (2006)a
	No definition: mapped trajectory	White et al. (2002, 2004)

Note. CDC = Centers for Disease Control and Prevention; USDHHS = U.S. Department of Health and Human Services. Although most definitions of a social smoker base the definition solely on the situations in which the person smokes, one study defined a social smoker as someone who smoked ≤5 CPD for at least 2 years, never exceeding that consumption for more than a few months (Wellman et al., 2006).

^aIncluded other elements in the definition beyond number of cigarettes smoked per day.