Table 2.

Association of Co-Occurring Cannabis and Tobacco vs. Cannabis Only Use with Cannabis Use Disorders.

Study	Definition of Co-Occurring Use	Diagnosis	Diagnosis Lifetime or Current	Adjusted Odds Ratio
Agrawal & Lynskey, 2009	Lifetime cannabis + smoked and smokeless tobacco	Cannabis abuse/dependence	Lifetime	1.68*
Agrawal & Lynskey, 2009	Lifetime cannabis + smoked tobacco	Cannabis abuse/dependence	Lifetime	1.55*
Agrawal & Lynskey, 2009	Lifetime cannabis + smokeless tobacco	Cannabis abuse/dependence	Lifetime	1.04
Agrawal, Lynskey, Madden, 2009	Lifetime cannabis + regular cigarette	Cannabis abuse	Lifetime	2.09*
Agrawal, Lynskey, Madden, 2009	Lifetime cannabis + regular cigarette	Cannabis dependence	Lifetime	2.30
Coffey, 2003	Young adult cannabis + adolescent persistent cigarette	Cannabis dependence at age 20	Current	1.9*
Coffey, 2003	Young adult cannabis + adolescent daily cigarette	Cannabis dependence at age 20	Current	0.71
Degenhardt, 2001	Current cannabis + current tobacco	Cannabis abuse/dependence	Current	5.00*
Degenhardt, 2001	Current cannabis + former tobacco	Cannabis abuse/dependence	Current	4.65*
Patton, 2006	Young adult cannabis + adolescent daily cigarette	Cannabis dependence at age 24	Current	27*
Swift, 2008	Adolescent cannabis + persistent cigarette	Cannabis dependence at age 24	Current	5.5*
Timberlake, 2009	Current (past month) “blunt” only use	Cannabis abuse	Current (past month)	2.2*
Timberlake, 2009	Current (past month) “blunt” only use	Cannabis dependence	Current (past month)	2.4*

Note. Reference group in each comparison was cannabis only use. Except where noted, “current” refers to past 12 months.

^*p < .05