Table 1.

Multinomial logistic regression of past-year simultaneous alcohol and marijuana (SAM) use, alcohol-only, marijuana-only, and non-simultaneous alcohol and marijuana use among 12th graders from 2000-2020

	Past-year simultaneous use Vs. no use	Past-year alcohol-only Vs. no use	Past-year marijuana-only Vs. no use	Past-year alcohol and marijuana use but not simultaneously Vs. no use
	aOR [95% CI]	aOR [95% CI]	aOR [95% CI]	aOR [95% CI]
Survey year (ref=2000-2005)
2006-2009	0.83 [0.73, 0.95]	0.94 [0.84, 1.05]	1.08 [0.79, 1.49]	0.88 [0.76, 1.02]
2010-2014	0.78 [0.70, 0.88]	0.71 [0.65, 0.78]	1.56 [1.18, 2.06]	0.91 [0.80, 1.02]
2015-2020	0.58 [0.51, 0.66]	0.54 [0.49, 0.60]	2.66 [2.04, 3.47]	0.85 [0.75, 0.96]
Sex (ref=male)
Female	0.82 [0.77, 0.88]	1.12 [1.06, 1.19]	0.85 [0.71, 1.01]	1.07 [0.99, 1.16]
Parental education (ref=finished college or more)
Some high school or lower	0.98 [0.86, 1.13]	0.95 [0.85, 1.07]	1.18 [0.83, 1.66]	1.05 [0.90, 1.23]
Finished high school or some college	1.12 [1.04, 1.21]	1.04 [0.98, 1.11]	1.22 [0.99, 1.49]	1.17 [1.07, 1.23]
Race/ethnicity (ref=white)
Black	0.50 [0.44, 0.56]	0.61 [0.55, 0.67]	1.95 [1.52, 2.50]	0.80 [0.70, 0.90]
Other	0.72 [0.65, 0.78]	0.85 [0.79, 0.92]	1.54 [1.23, 1.94]	0.93 [0.84, 1.03]

Note: aOR=Adjusted odds ratio. Alcohol-only is defined as past-year alcohol use and no report of past-year marijuana or simultaneous use. Marijuana-only is defined as past-year marijuana use and no report of past-year alcohol or simultaneous use.

Model adjusts for survey year, sex, parental education, race/ethnicity, and also adjusted for survey mode (not shown)