Table 2.

Correlates of exclusive versus concurrent past 30-day nicotine and cannabis use among youth aged 16–19 residing in the United States, Canada, and England

	Odds of concurrent use vs. exclusive nicotine use n=1,928	Odds of concurrent use vs. exclusive cannabis use n=1,080
	aOR (95% CI)*	aOR (95% CI)†
Age	1.10 (0.96–1.27)	1.04 (0.89–1.23)
Sex
Female	1.00 (ref)	1.00 (ref)
Male	0.90 (0.68–1.19)	1.34 (0.97–1.86)
Race-ethnicity
Non-white	1.00 (ref)	1.00 (ref)
White	0.81 (0.59–1.11)	1.49 (1.07–2.09)
Country of residence
USA	1.00 (ref)	1.00 (ref)
Canada	1.68 (1.16–2.44)	1.01 (0.70–1.46)
England	0.84 (0.60–1.17)	1.68 (1.12–2.51)
No. of computers	0.99 (0.90–1.09)	0.86 (0.78–0.95)
Depression	1.03 (0.95–1.11)	1.10 (1.01–1.19)
Anxiety	1.04 (0.96–1.12)	0.99 (0.91–1.08)
Alcohol use
Never	1.00 (ref)	1.00 (ref)
Ever	2.71 (1.73–4.26)	1.42 (0.81–2.48)
Harm perception of smoked cannabis	0.52 (0.45–0.60)	0.84 (0.70–1.02)
Past 30-day nicotine use
Exclusive single-combustible use	1.00 (ref)	---
Exclusive nicotine e-cigarette use	0.55 (0.37–0.83)	---
Dual/poly nicotine use	1.89 (1.38–2.58)	---

Bold values denote statistically significant findings (p<0.05).

^*Adjusted for age, sex, race-ethnicity, country of residence, number of computers, depression, anxiety, alcohol use, harm perceptions of smoked cannabis, & past 30-day nicotine use.

^†Adjusted for age, sex, race-ethnicity, country of residence, number of computers, depression, anxiety, alcohol use, & harm perceptions of smoked cannabis.

Age, no. of computers, depression, anxiety and harm perceptions of smoked cannabis were modeled as continuous variables.