Table 3.

Multivariable Mixed-effects Logistic Regression Modeling of Past 30-Day Waterpipe Tobacco Smoking (N=3,770)

Characteristic*	AOR	95% CI	P-value
Demographics
Gender (male vs. female)	1.55	1.24, 1.93	<0.001
Race/Ethnicity			4 df p=0.315
African-American	0.76	0.42, 1.35	0.344
Asian/Pacific Islander	1.70	0.72, 4.02	0.223
Hispanic	0.99	0.59, 1.68	0.981
Other	0.62	0.33, 1.16	0.132
WhiteRC	-	-	-
Class year			4 df p<0.001
FreshmanRC	-	-	-
Sophomore	0.71	0.52, 0.96	0.028
Junior	0.61	0.43, 0.87	0.006
Senior	0.38	0.26, 0.56	<0.001
5th yr.	0.42	0.23, 0.76	0.004
Residence location (on- vs. off-campus)	0.91	0.68, 1.22	0.536
Greek member/pledge (yes vs. no)	0.95	0.69, 1.30	0.747
Monthly spending money			5 df p=0.521
Less than $100RC	-	-	-
$100–$199	0.94	0.69, 1.26	0.661
$200–$299	1.06	0.76, 1.49	0.729
$300–$399	1.12	0.75, 1.67	0.585
$400–$499	1.38	0.81, 2.33	0.237
$500 or more	0.80	0.50, 1.28	0.349
Mother’s highest education
4 year college degree or higher	0.98	0.77, 1.26	0.894
Some college or lessRC	-	-	-
Father’s highest education
4 year college degree or higher	1.05	0.81, 1.35	0.722
Some college or lessRC	-	-	-
Health-Risk Behaviors
Cigarette smoker type			3 df p<0.001
Never smoker RC	-	-	-
Former/experimenter	1.95	1.45, 2.63	<0.001
Current nondaily	2.59	1.92, 3.49	<0.001
Current daily	2.80	1.85, 4.23	<0.001
Lifetime illegal drug use (yes vs. no)	3.13	2.14, 4.56	<0.001
Past 30-day marijuana use (yes vs. no)	4.43	3.46, 5.66	<0.001
Past 30-day drinking (yes vs. no)	2.20	1.52, 3.17	<0.001
Harm Perceptions
Waterpipe vs. cigarette			2 df p<0.001
Less harmful	2.66	2.10, 3.38	<0.001
As harmful RC	-	-	-
More harmful	1.15	0.82, 1.61	0.431
School-Level Variables
Private university (yes vs. no)	0.84	0.48, 1.47	0.537
Commercial waterpipe venue in community (yes vs. no)	1.60	1.10, 2.33	0.014

^*Also adjusted for school as a random effect; RC = reference category