Under the influence: examination of prevalence and correlates of alcohol and marijuana consumption in relation to youth driving and passenger behaviours in Canada. A cross-sectional study

Leia M. Minaker; Aaron Bonham; Tara Elton-Marshall; Cesar Leos-Toro; T. Cameron Wild; David Hammond

doi:10.9778/cmajo.20160168

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Tables

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Table 1: Characteristics of grade 9-12 students who participated in the 2014-2015 Canadian Student Tobacco, Alcohol and Drugs Survey

Characteristic	Sample size	Weighted %*(99% CI)
Canada (total)	24 650
Sex
Female	12 514	48.6 (48.6-48.6)
Male	12 136	51.4 (51.4-51.5)
Grade
9	7200	25.2 (25.2-25.2)
10	6986	25.3 (25.2-5.3)
11	6193	25.5 (25.5-25.5)
12	4271	24.0 (24.0-24.1)
Ethnicity
White	16 970	60.9 (52.3-69.4)
Black	859	4.7 (3.0-6.3)
Asian	3597	22.7 (14.6-30.9)
Latin American	434	2.3 (1.2-3.3)
Aboriginal	1684	4.7 (3.0-6.3)
Other	955	4.8 (3.5-6.0)
Missing values	151
Province
British Columbia	3862	12.9 (12.6-13.3)
Alberta	3957	10.8 (10.5-11.1)
Saskatchewan	1895	3.2 (3.1-3.3)
Manitoba	1863	4.0 (3.9-4.1)
Ontario	3657	46.3 (45.1-47.6)
Quebec	2608	15.9 (15.5-16.3)
Nova Scotia	2778	2.7 (2.6-2.7)
Prince Edward Island	1446	0.5 (0.5-0.5)
Newfoundland and Labrador	2458	1.4 (1.3-1.4)
School socioeconomic status
Low median	12 066	44.9 (28.6-61.1)
High median	12 584	55.1 (38.9-71.4)
Urban
Yes	15 801	79.5 (68.1-90.9)
No	8849	20.5 (9.1-31.9)*
Ever binge drink
Does not drink	8316	38.8 (34.4-43.2)
Drinks but no binging	4052	18.1 (16.2-20.1)
Binge drinks	10 955	43.1 (39.6-46.5)
Missing values	1327

Note: CI = confidence interval.

*Presented as a proportion of complete data (i.e., does not include missing values).

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Table 2: Weighted prevalence and logistic regression analysis* of variables related to the odds of driving within an hour of drinking at least 1 drink among 10 411 grade 11-12 students

Variable	In last 30 d		Ever
Variable	Weighted prevalence (95% CI), %	Odds ratio (99% CI)	Weighted prevalence (95% CI), %	Odds ratio (99% CI)
Canada (total)	3.5 (2.8-4.2)		9.1 (7.9-10.3)
Sex
Female	2.7 (1.8-3.5)	0.516 (0.264-1.011)	6.8 (5.3-8.2)	0.477 (0.290-0.786)
Male	4.3 (3.2-5.4)	Reference	11.4 (9.4-13.4)	Reference
Grade
11	2.9 (2.2-3.6)	Reference	7.1 (6.1-8.1)	Reference
12	4.2 (3.2-5. 1)	1.406 (0.883-2.240)	11.3 (9.2-13.4)	1.642 (1.115-2.417)
Ethnicity
White	3.7 (2.7-4.6)	Reference	10.4 (8.5-12.3)	Reference
Black	†	2.645 (0.730-9.584)	7.1(2.6-11.5)‡	1.096 (0.409-2.940)
Asian	1.6 (0.7-2.5)‡	1.000 (0.417-2.399)	4.4(2.8-5.9)‡	0.850 (0.440-1.643)
Latin American	†	5.238 (0.278-98.553)	16.7(6.5-27.0)‡	2.658 (0.405-17.433)
Aboriginal	5.8 (2.6-9.1)‡	1.441 (0.518-4.007)	14.7 (9.5-19.9)‡	1.031 (0.529-2.008)
Other	†	2.433 (0.743-7.968)	10.3(4.7-15.3)‡	1.694 (0.549-5.234)
Province
British Columbia	4.5 (3.1-6.0)	1.583 (0.681-3.677)	12.4 (9.4-15.4)	2.065 (1.125-3.791)
Alberta	3.4 (2.2-4.5)‡	1.339 (0.558-3.214)	9.5 (7.2-11.8)	1.699 (1.033-2.795)
Saskatchewan	9.8 (4.9-14.8)‡	3.679 (1.472-9.194)	18.5 (11.4-25.6)‡	2.926 (1.510-5.670)
Manitoba	2.4 (1.5-3.4)‡	0.630 (0.254-1.564)	11.1(5.8-16.4)‡	1.474 (0.625-3.477)
Ontario	2.3 (1.5-3.3)‡	Reference	6.3 (4.4-8.2)	Reference
Quebec	†	1.007 (0.367-2.764)	9.0 (7.0-11.0)	1.213 (0.656-2.243)
Nova Scotia	4.0 (2.3-5.6)‡	1.109 (0.433-2.839)	10.0 (7.9-12.1)	1.299 (0.796-2.120)
Prince Edward Island	3.8 (2.7-4.9)	1.174 (0.562-2.458)	11.7 (8.3-15.0)	1.462 (0.799-2.674)
Newfoundland and Labrador	5.5 (4.4-6.5)	1.716 (0.827-3.563)	13.9(9.2-18.6)‡	1.828 (1.042-3.208)
School socioeconomic status
Low median	3.6 (2.6-4.6)	Reference	10.5(8.0-13.0)	Reference
High median	3.5 (2.5-4.4)	1.219 (0.605-2.457)	8.0 (6.7-9.4)	0.889 (0.518-1.526)
Urban
Yes	2.6 (1.9-3.3)	Reference	7.2 (5.9-8.5)	Reference
No	7.6 (5.9-9.4)	2.326 (1.312-4.125)	17.6 (13.7-21.4)	1.712 (1.163-2.520)
Drinking behaviour
Does not drink	†	Reference	†	Reference
Drinks but no binging	0.7 (0.4-1.0)‡	1.113 (0.146-8.470)	2.9 (1.6-4.2)‡	2.391 (0.527-10.839)
Binge drinks	5.9 (4.9-7.0)	8.559 (1.188-61.655)	15.1 (13.0-17.1)	12.725 (3.284-49.308)

Note: CI = confidence interval.

*All logistic regressions were conducted with the use of a complete-case methods approach, so the results presented here are among all cases with complete data.

†High sampling variability/insufficient sample size; data suppressed.

‡Moderate sampling variability; interpret with caution.

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Table 3: Weighted prevalence and logistic regression analysis* of variables related to the odds of driving within 2 hours of using marijuana among 10 411 grade 11-12 students

Variable	In last 30 d		Ever
Variable	Weighted prevalence (95% CI), %	Odds ratio (99% CI)	Weighted prevalence (95% CI), %	Odds ratio (99% CI)
Canada (total)	4.7 (3.9-5.5)		9.4 (8.3-10.4)
Sex
Female	3.2 (2.1-4.3)†	0.448 (0.240-0.834)	7.1 (5.6-8.6)	0.517 (0.333-0.805)
Male	6.1 (4.9-7.3)	Reference	11.5 (10.0-13.0)	Reference
Grade
11	3.6 (2.8-4.3)	Reference	7.2 (6.1-8.4)	Reference
12	6.0 (4.5-7.4)	1.533 (0.959-2.452)	11.6 (9.8-13.5)	1.584 (1.072-2.339)
Ethnicity
White	4.7 (3.7-5.8)	Reference	10.2 (8.9-11.4)	Reference
Black	‡	2.610 (0.823-8.274)	8.4 (3.5-13.3)†	1.337 (0.465-3.842)
Asian	2.3 (1.0-3.6)†	0.982 (0.438-2.198)	4.0 (2.6-5.4)†	0.733 (0.393-1.369)
Latin American	‡	4.189 (0.273-64.273)	‡	3.698 (0.722-18.934)
Aboriginal	13.2 (9.1-17.2)	2.529 (1.244-5.143)	23.0 (16.9-29.2)	2.005 (1.140-3.526)
Other	‡	1.126 (0.308-4.114)	10.0 (4.4-15.5)†	1.692 (0.690-4.146)
Province
British Columbia	6.9 (4.8-9.0)‡	1.849 (0.676-5.062)	12.5 (8.6-16.4)	1.757 (0.815-3.787)
Alberta	3.5 (2.0-5.0)‡	0.992 (0.400-2.459)	8.0 (6.2-9.8)	1.241 (0.782-1.970)
Saskatchewan	10.5 (6.0-14.9)‡	2.428 (1.135-5.194)	20.0 (11.7-28.3)‡	2.665 (1.519-4.677)
Manitoba	4.8 (3.0-6.7)‡	1.050 (0.435-2.534)	14.1 (8.3-20.0)‡	1.757 (0.832-3.710)
Ontario	3.5 (2.1-4.9)‡	Reference	7.2 (5.8-8.6)	Reference
Quebec	3.5 (2.2-4.7)‡	0.850 (0.348-2.075)	6.9 (4.7-9.0)	0.773 (0.450-1.327)
Nova Scotia	7.6 (6.5-8.6)	1.842 (1.092-3.107)	15.2 (13.0-17.3)	1.867 (1.329-2.621)
Prince Edward Island	10.9 (9.1-12.6)	2.892 (1.478-5.656)	16.3 (14.0-18.6)	1.993 (1.375-2.888)
Newfoundland and Labrador	10.1 (8.1-12.2)	2.723 (1.476-5.023)	18.9 (16.6-21.3)	2.394 (1.582-3.625)
School socioeconomic status
Low median	5.0 (3.4-6.6)	Reference	10.3 (8.2-12.4)	Reference
High median	4.4 (3.4-5.4)	0.989 (0.479-2.043)	8.6 (7.3-9.9)	1.037 (0.619-1.738)
Urban
Yes	4.2 (3.3-5.1)	Reference	8.2 (7.0-9.4)	Reference
No	6.8 (4.0-9.6)‡	1.029 (0.537-1.974)	14.5 (11.5-17.4)	1.228 (0.891-1.693)
Drinking behaviour
Does not drink	†	Reference	†	Reference
Drinks but no binging	0.7 (0.4-1.0)‡	0.879 (0.175-4.428)	1.5 (0.8-2.2)‡	1.089 (0.366-3.244)
Binge drinks	8.0 (6.7-9.2)	10.128 (2.283-44.940)	16.0 (14.4-17.6)	12.934 (4.360-38.366)

Note: CI = confidence interval.

*All logistic regressions were conducted with the use of a complete-case methods approach, so the results presented here are among all cases with complete data.

†Moderate sampling variability; interpret with caution.

‡High sampling variability/insufficient sample size; data suppressed.

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Table 4: Logistic regression analysis* of variables related to the odds of riding with a driver who had had at least 1 drink within the previous hour among 22 684 grade 9-12 students

Variable	In last 30 d		Ever
Variable	Weighted prevalence (95% CI), %	Odds ratio (99% CI)	Weighted prevalence (95% CI), %	Odds ratio (99% CI)
Canada (total)	11.0 (10.2-11.9)		34.6 (32.4-36.9)
Sex
Female	12.2 (10.9-13.6)	1.233 (0.990-1.536)	38.2 (35.5-41.0)	1.337 (1.159-1.543)
Male	9.9 (8.9-10.9)	Reference	31.2 (29.1-33.3)	Reference
Grade
9	9.1 (7.6-10.6)	Reference	29.8 (27.1-32.5)	Reference
10	11.1 (9.9-12.2)	0.952 (0.698-1.301)	34.5 (31.9-37.2)	1.006 (0.847-1.196)
11	12.4 (11.1-13.7)	0.995 (0.737-1.344)	36.9 (34.7-39.1)	1.045 (0.869-1.257)
12	11.6 (9.7-13.5)	0.879 (0.652-1.186)	37.3 (32.9-41.7)	1.008 (0.809-1.255)
Ethnicity
White	13.4 (12.2-14.6)	Reference	39.6 (36.8-42.5)	Reference
Black	7.9 (4.3-11.5)†	0.806 (0.428-1.519)	24.4 (16.6-32.2)	0.691 (0.441-1.084)
Asian	5.5 (4.6-6.5)	0.682 (0.492-0.946)	22.4 (20.5-24.3)	0.798 (0.626-1.017)
Latin American	7.7 (4.8-10.7)†	0.604 (0.342-1.066)	39.7 (32.4-47.0)	1.112 (0.697-1.774)
Aboriginal	12.4 (9.8-15.0)	0.860 (0.564-1.312)	42.7 (37.6-47.8)	1.014 (0.740-1.389)
Other	11.0 (8.1-13.9)	1.051 (0.662-1.667)	30.1 (22.3-37.9)	0.874 (0.568-1.344)
Province
British Columbia	11.4 (8.8-13.9)	1.237 (0.860-1.780)	34.9 (28.7-41.1)	1.059 (0.773-1.452)
Alberta	9.9 (7.6-12.1)	1.200 (0.808-1.781)	31.3 (28.7-33.8)	1.009 (0.740-1.376)
Saskatchewan	14.7 (11.3-18.1)	1.444 (1.029-2.026)	38.7 (29.1-48.2)	1.070 (0.702-1.630)
Manitoba	9.1 (7.0-11.1)	0.888 (0.578-1.366)	30.5 (24.4-36.6)	0.790 (0.516-1.210)
Ontario	9.1 (7.8-10.3)	Reference	30.9 (26.7-35.1)	Reference
Quebec	15.4 (12.4-18.5)	1.309 (0.881-1.946)	43.8 (40.0-47.5)	1.204 (0.855-1.694)
Nova Scotia	9.2 (7.8-10.7)	0.807 (0.615-1.060)	30.6 (27.8-33.3)	0.799 (0.588-1.087)
Prince Edward Island	10.6 (9.0-12.2)	0.939 (0.646-1.365)	34.8 (31.9-37.8)	0.895 (0.648-1.236)
Newfoundland and Labrador	10.0 (8.3-11.7)	0.864 (0.684-1.090)	31.4 (26.2-36.7)	0.789 (0.579-1.076)
School socioeconomic status
Low median	12.2 (10.9-13.6)	Reference	40.0 (37.0-43.0)	Reference
High median	10.1 (8.8-11.4)	0.997 (0.807-1.231)	30.3 (27.1-33.4)	0.789 (0.620-1.004)
Urban
Yes	9.6 (8.6-10.7)	Reference	30.7 (28.3-33.3)	Reference
No	16.4 (14.1-18.6)	1.094 (0.841-1.425)	49.5 (46.2-52.8)	1.394 (1.128-1.723)
Drinking behaviour
Does not drink	3.5 (2.8-4.1)	Reference	17.0 (14.8-19.2)	Reference
Drinks but no binging	8.5 (6.8-9.5)	2.259 (1.432-3.561)	32.9 (29.1-36.8)	2.072 (1.600-2.685)
Binge drinks	18.5 (17.1-20.0)	5.425 (3.681-7.995)	49.8 (47.1-52.6)	3.893 (3.138-4.829)

Note: CI = confidence interval.

*All logistic regressions were conducted with the use of a complete-case methods approach, so the results presented here are among all cases with complete data.

†Moderate sampling variability; interpret with caution.

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Table 5: Logistic regression analysis* of variables related to the odds of riding with a driver who had used marijuana within 2 hours of driving among 22 504 grade 9-12 students

Variable	In last 30 d		Ever
Variable	Weighted prevalence (95% CI), %	Odds ratio (99% CI)	Weighted prevalence (95% CI), %	Odds ratio (99% CI)
Canada (total)	9.0 (7.9-10.1)		19.8 (18.0-21.6)
Sex
Female	8.9 (7.7-10.2)	0.892 (0.627-1.269)	19.9 (18.0-21.8)	0.909 (0.705-1.171)
Male	9.1 (7.6-10.7)	Reference	19.6 (17.4-21.8)	Reference
Grade
9	4.0 (2.9-5.0)	Reference	9.1 (6.9-11.3)	Reference
10	6.4 (5.3-7.5)	1.325 (0.946-1.856)	15.5 (13.0-18.0)	1.338 (0.942-1.900)
11	10.6 (9.2-11.9)	1.872 (1.196-2.929)	22.5 (20.5-24.4)	1.893 (1.310-2.735)
12	15.4 (11.8-19.1)	2.546 (1.452-4.463)	32.4 (27.4-37.4)	2.947 (1.873-4.638)
Ethnicity
White	10.3 (8.6-11.9)	Reference	22.9 (20.0-25.8)	Reference
Black	8.2 (4.4-12.1)†	1.278 (0.605-2.702)	17.0 (11.7-22.2)	1.097 (0.599-2.011)
Asian	4.3 (3.1-5.5)	0.730 (0.499-1.069)	8.3 (7.0-9.5)	0.540 (0.338-0.863)
Latin American	6.6 (3.5-9.8)†	0.817 (0.336-1.987)	23.9 (17.5-30.3)	1.397 (0.625-3.124)
Aboriginal	20.1 (16.5-23.7)	2.068 (1.453-2.942)	38.8 (33.0-44.6)	1.938 (1.364-2.755)
Other	7.3 (4.1-10.4)†	0.986 (0.441-2.206)	17.5 (11.6-23.5)†	1.055 (0.518-2.150)
Province
British Columbia	12.8 (9.7-15.9)	1.807 (1.054-3.098)	24.9 (19.6-30.3)	1.722 (1.119-2.650)
Alberta	8.1 (6.6-9.6)	1.204 (0.760-1.907)	18.5 (16.9-20.1)	1.336 (0.946-1.885)
Saskatchewan	14.3 (8.6-20.0)†	1.452 (0.876-2.407)	27.1 (15.9-38.4)†	1.319 (0.755-2.305)
Manitoba	10.0 (7.2-12.9)	1.015 (0.587-1.755)	22.5 (16.7-28.2)	1.139 (0.644-2.013)
Ontario	7.8 (5.7-9.8)	Reference	17.2 (14.2-20.1)	Reference
Quebec	6.7 (4.5-9.0)†	0.824 (0.503-1.351)	17.9 (12.5-23.4)†	0.942 (0.546-1.625)
Nova Scotia	13.8 (11.9-15.7)	1.612 (1.008-2.576)	27.8 (25.4-30.3)	1.706 (1.142-2.548)
Prince Edward Island	15.3 (13.6-17.1)	1.863 (1.192-2.912)	29.2 (26.9-31.6)	1.743 (1.181-2.571)
Newfoundland and Labrador	15.9 (12.6-19.3)	1.945 (1.104-3.427)	31.3 (28.1-34.5)	1.942 (1.265-2.980)
School socioeconomic status
Low median	10.1 (8.0-12.2)	Reference	22.9 (19.2-26.6)	Reference
High median	8.2 (6.7-9.6)	1.038 (0.561-1.918)	17.2 (14.9-19.5)	0.948 (0.611-1.472)
Urban
Yes	8.5 (7.2-9.8)	Reference	18.2 (16.1-20.4)	Reference
No	11.1 (8.7-13.5)	0.854 (0.607-1.202)	25.5 (21.9-29.2)	0.888 (0.635-1.244)
Drinking behaviour
Does not drink	1.2 (0.8-1.7)†	Reference	3.2 (2.6-3.8)	Reference
Drinks but no binging	3.3 (2.5-4.0)	2.320 (1.451-3.710)	9.4 (8.1-10.7)	2.608 (1.945-3.497)
Binge drinks	18.1 (16.1-20.1)	14.173 (8.335-24.099)	37.5 (34.5-40.5)	13.693 (10.300-18.203)

Note: CI = confidence interval.

*All logistic regressions were conducted with the use of a complete-case methods approach, so the results presented here are among all cases with complete data.

†Moderate sampling variability; interpret with caution.