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Bidi and Hookah Use Among Canadian Youth: An Examination of Data From the 2006 Canadian Youth Smoking Survey
Journal of Adolescent Health 49 (2011) 102–104
www.jahonline.org Adolescent health brief
Bidi and Hookah Use Among Canadian Youth: An Examination of Data From the 2006 Canadian Youth Smoking Survey Wing C. Chan, M.P.H.a, Scott T. Leatherdale, Ph.D.b,c,d,*, Robin Burkhalter, M.Math.c, and Rashid Ahmed, M.Sc.c a
Department of Health Studies and Gerontology, University of Waterloo, Waterloo, Ontario, Canada Department of Prevention and Cancer Control, Cancer Care Ontario, Toronto, Ontario, Canada c Propel Centre for Population Health Impact, Canadian Cancer Society and the University of Waterloo, Waterloo, Ontario, Canada d Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada b
Article history: Received May 25, 2010; Accepted November 17, 2010 Keywords: Bidi; Hookah; Prevalence; Prevention; Public health; Tobacco; Youth
A B S T R A C T
Purpose: To examine the prevalence and associated factors of bidi and hookah use among Canadian youth. Methods: Data from 41,886 grade 7 to 12 youth were used to examine factors associated with bidi and hookah use. Results: Youth who are current or former cigarette smokers, have tried marijuana or alcohol, were more likely to use bidi or hookah. Conclusions: Results suggest bidi and hookah use may be an emerging issue in tobacco control among youth. Findings also support an integrated approach where future prevention efforts should address multiple risk behaviors. 䉷 2011 Society for Adolescent Health and Medicine. All rights reserved.
Bidi (also known as beedi or beeri) is a hand-rolled, unfiltered cigarette of tobacco in tendu leaf [1], and hookah (also known as shisha, hubble-bubble, or nargile) is a water pipe that is used for smoking tobacco [2]. In Canada, both of these alternative tobacco products have become more accessible and represent affordable tobacco alternatives in a variety of flavors that appeal to youth. Recent studies have identified that the prevalence of bidi and hookah use has increased in North America, especially among youth [3,4]. This is a cause for concern as bidi and hookah contain many of the same harmful toxicants as cigarettes, such as tar, nicotine, and carbon monoxide [1,5]. Moreover, research has suggested that bidi and hookah users are at increased risk for some cancers and cardiovascular disease [1,5]. Considering that additional research on this emerging public health issue is required, the current study examined bidi and hookah use and behavior among Canadian youth.
* Address correspondence to: Scott T. Leatherdale, Ph.D., Department of Prevention and Cancer Control, Cancer Care Ontario, 620 University Avenue, Toronto, Ontario, Canada, M5G 2L7. E-mail address: [email protected] (S.T. Leatherdale).
Methods This study used nationally representative data collected from 41,886 students in grades 7–12 as part of the 2006 –2007 Canadian Youth Smoking Survey (YSS). Detailed information on the sample design, survey rates, and measures for the 2006 –2007 YSS is available on the YSS Web site (http://www.yss.uwaterloo. ca). In brief, the target population consisted of Canadian youth attending public and private elementary and secondary schools in 10 Canadian provinces. The YSS was administered to students during class time and participants were not provided compensation. Ever use of bidis or hookah was defined as those who have tried smoking bidis or using hookah to smoke tobacco. Current users of bidis or hookah were defined as those who have smoked bidis or used hookah to smoke tobacco in the last 30 days. Current smokers were defined as those who have smoked at least 100 cigarettes in his/her lifetime and have smoked in the 30 days preceding the survey. Former smokers were defined as those who smoked at least 100 cigarettes in his/her lifetime and had not smoked at all in the 30 days preceding the survey. Nonsmokers were defined as those who reported not having smoked 100 cigarettes in their lifetime and not having smoked in the 30 days
1054-139X/$ - see front matter 䉷 2011 Society for Adolescent Health and Medicine. All rights reserved. doi:10.1016/j.jadohealth.2010.11.250
W.C. Chan et al. / Journal of Adolescent Health 49 (2011) 102–104
Table 1 Descriptive analyses of bidi and hookah use among youth in grades 7–12, Canada 2006 Sample characteristic
Prevalence (%)a Ever use of Current use Ever use of Current use bidis of bidis hookah of hookah
All students Grade level 7th 8th 9th 10th 11th 12th Gender Male Female Provinceb Atlantic Canadac Quebec Ontario Prairiesd British Columbia Cigarette smoking status Nonsmoker Former smoker Current smoker Ever tried marijuana Yes No Ever tried alcohol Yes No a b
c
d e
1.7
.7
6.8
2.7
.4 .8 1.7 2.1 3.3 1.7
.3 .4 .9 .7 1.2 .5
1.0 3.2 5.0 8.6 11.8 12.1
.5 1.1 2.3 3.4 4.3 5.0
2.1 1.2
.9 .4
8.1 5.5
3.6 1.8
1.9 3.5 1.0 .8 2.4
.8 1.0 .5 .4 1.0
4.0 10.5 5.6 4.8 10.0
2.0 3.9 2.3 2.0 3.9
.8 8.9 11.0
.2 e 5.6
4.7 22.1 30.7
1.5 4.8 17.9
5.0 .2
1.8 .1
18.9 1.8
8.0 .5
2.3 .2
.8 .2
9.4 1.0
3.7 .6
Analyses were conducted by using weighted data. It is illegal to sell or give tobacco to anyone under the age of 18 in the provinces of Alberta, Manitoba, Quebec, and Saskatchewan, and under the age of 19 in the provinces of British Columbia, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, and Prince Edward Island. Atlantic Canada (New Brunswick, Prince Edward Island, Nova Scotia, Newfoundland and Labrador). Prairies (Alberta, Saskatchewan, Manitoba). Data were suppressed because of the unweighted sample size being less than 30.
103
preceding the survey. Ever use of alcohol or marijuana was defined as those who have had a drink of alcohol or tried marijuana. Descriptive analyses of bidis and hookah use were performed according to grade, sex, province, smoking status, marijuana use, and alcohol use. For the descriptive analyses, survey weights were used to adjust for nonresponse between provinces and groups, thereby minimizing any bias in the analyses caused by differential response rates across regions or groups. Four logistic regression models were used to examine factors associated with ever use of bidis (Model 1), current use of bidis (Model 2), ever use of hookah (Model 3), and current use of hookah (Model 4). The statistical package SAS 8.02 (Cary, NC) was used for all analyses. Results Descriptive analyses results are presented in Table 1. Students reported using bidi and hookah, although rates of ever and current hookah use are higher than ever or current use of bidis. Male youth and youth in higher grades were more likely to use bidi or hookah. The prevalence of hookah or bidi use was higher among youth who are current or former smokers, and youth who have ever used marijuana or alcohol. Results of the logistic regression analyses are presented in Table 2. Male youth were more likely to report ever and current use of bidis and hookah compared with female youth. Current or former smokers and youth who have tried marijuana were more likely to have ever tried bidi or hookah, and were also more likely to be current bidi or hookah users. Youth who have tried alcohol were more likely to have ever smoked a bidi or used hookah, but less likely to be current bidi users. Discussion We identified that youth who are current or former smokers were more likely to use or have used bidi or hookah compared with nonsmokers, and those who had tried marijuana were more likely to use or have used bidi or hookah. These findings are consistent with existing research [3,4]. We also identified that youth who have tried alcohol were also more likely to have tried
Table 2 Logistic regression analyses examining factors associated with bidi and hookah use among youth in grades 7–12, Canada 2006 Parameters
Sex Smoking status
Ever used marijuana Ever drank alcohol
Adjusted odds ratioa (95% CI) Coding
Model 1 ever use of bidis
Model 2 current use of bidis
Model 3 ever use of hookah
Model 4 current use of hookah
Female Male Non-smoker Former smoker Current smoker No Yes No Yes c statistic
1.0 1.7 (1.5–1.9)*** 1.0 4.9 (3.6–6.6)*** 5.1 (4.4–5.9)*** 1.0 9.0 (6.9–11.7)*** 1.0 1.7 (1.1–2.7)* .882
1.0 2.1 (1.7–2.7)*** 1.0 4.6 (2.4–8.7)* 12.4 (9.4–16.4)*** 1.0 6.2 (4.0–9.7)*** 1.0 .7 (.4–1.1)* .877
1.0 1.4 (1.3–1.5)*** 1.0 2.4 (1.9–2.9)** 3.0 (2.8–3.3)*** 1.0 5.4 (4.9–5.9)*** 1.0 2.3 (1.9–2.7)*** .868
1.0 1.9 (1.7–2.1)*** 1.0 1.4 (1.0–2.0)** 5.1 (4.6–5.8)*** 1.0 6.9 (5.7–8.3)*** 1.0 1.0 (.7–1.2)* .876
Model 1: 1 ⫽ yes (n ⫽ 964), 0 ⫽ not stated (n ⫽ 57,389). Model 2: 1 ⫽ yes (n ⫽ 380), 0 ⫽ not stated (n ⫽ 57,973). Model 3: 1 ⫽ yes (n ⫽ 3,988), 0 ⫽ not stated (n ⫽ 54,365). Model 4: 1 ⫽ yes (n ⫽ 1,595), 0 ⫽ not stated (n ⫽ 56,758). a Odds ratios adjusted for all other variables in the table and controlling for grade and province. * p ⬍ .05, ** p ⬍ .01, *** p ⬍ .001.
104
W.C. Chan et al. / Journal of Adolescent Health 49 (2011) 102–104
bidi or hookah. The comorbid use of these substances is consistent with research that has previously identified the clustering of marijuana, alcohol, and tobacco among Canadian youth [6] and further highlights the importance of implementing co-morbid substance use prevention programs in schools [7]. A common ethos in school-based prevention programming is to focus prevention activities on reducing the uptake of one substance, with the goal of reducing its prevalence of use rather than focusing on preventing substance use more globally [8]. Our data provide evidence to support the integration of school-based prevention efforts for multiple risk behaviors that are related and to commence such programs no later than elementary school, which is consistent with recommendations made by recent studies [9]. This study has several limitations common to survey research. Although the response rate was high and the data were weighted to help account for nonresponse, the findings are nevertheless subject to sample bias. In addition, the findings likely reflect some underreporting for substance use as is common in survey research [10]. The cross-sectional nature of the data does not allow for causal inferences regarding the association between bidi and hookah use and the correlates examined. Longitudinal data are required to determine the temporal sequence of the associations examined. Future research on bidi and hookah use is warranted. Developing a better understanding of the prevalence of bidi and hookah use, and factors associated with their use among youth is important because it can provide insight to guide the provision and timing of prevention interventions. Our results not only demonstrate for the first time the scope of this emerging issue within Canada, but also address gaps in current literature on the factors associated with bidi and hookah use. Acknowledgments The authors thank the Propel Centre for Population Health Impact and the Interdisciplinary Capacity Enhancement Pro-
gram at the University of Waterloo for providing support for this project. Dr Leatherdale is a Cancer Care Ontario Research Chair in Population Studies. The 2006 –2007 Youth Smoking Survey is a product of a pan-Canadian capacity building project that includes Canadian tobacco control researchers from all provinces and provides training opportunities for university students at all levels. The article has been made possible through a financial contribution from Health Canada. The views expressed herein do not necessarily represent the views of Health Canada. References [1] Rahman M, Fukui T. Bidi smoking and health. Public Health 2000;114: 123–7. [2] Dugas E, Tremblay M, Low NC, et al. Water-pipe smoking among North American youths. Pediatrics 2010;125:1184 –9. [3] Barnett TE, Curbow BA, Weitz JR, et al. Water pipe tobacco smoking among middle and high school students. Am J Public Health 2009;99: 2014 –19. [4] Delnevo CD, Pevzner ES, Hrywna M, Lewis MJ. Bidi cigarette use among young adults in 15 states. Prev Med 2004;39:207–11. [5] Eissenberg T, Shihadeh A. Waterpipe tobacco and cigarette smoking: Direct comparison of toxicant exposure. Am J Prev Med 2009;37:518 – 23. [6] Leatherdale ST, Hammond D, Ahmed R. Alcohol, marijuana, and tobacco use patterns among youth in Canada. Cancer Causes Control 2008;19: 361–9. [7] Ringwalt C, Hanley S, Vincus AA, et al. The prevalence of effective substance use prevention curricula in the nation’s high schools. J Prim Prev 2008;29: 479 – 88. [8] Poulin C, Elliott D. Alcohol, tobacco and cannabis use among Nova Scotia adolescents: Implications for prevention and harm reduction. CMAJ 1997; 156:1387–93. [9] Camenga DR, Klein JD, Roy J. The changing risk profile of the American adolescent smoker: Implications for prevention programs and tobacco interventions. J Adolesc Health 2006;39:120.e1–10. [10] Bovet P, Viswanathan B, Faeh D, Warren W. Comparison of smoking, drinking, and marijuana use between students present or absent on the day of a school-based survey. J Sch Health 2006;76:133–7.
www.jahonline.org Adolescent health brief
Bidi and Hookah Use Among Canadian Youth: An Examination of Data From the 2006 Canadian Youth Smoking Survey Wing C. Chan, M.P.H.a, Scott T. Leatherdale, Ph.D.b,c,d,*, Robin Burkhalter, M.Math.c, and Rashid Ahmed, M.Sc.c a
Department of Health Studies and Gerontology, University of Waterloo, Waterloo, Ontario, Canada Department of Prevention and Cancer Control, Cancer Care Ontario, Toronto, Ontario, Canada c Propel Centre for Population Health Impact, Canadian Cancer Society and the University of Waterloo, Waterloo, Ontario, Canada d Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada b
Article history: Received May 25, 2010; Accepted November 17, 2010 Keywords: Bidi; Hookah; Prevalence; Prevention; Public health; Tobacco; Youth
A B S T R A C T
Purpose: To examine the prevalence and associated factors of bidi and hookah use among Canadian youth. Methods: Data from 41,886 grade 7 to 12 youth were used to examine factors associated with bidi and hookah use. Results: Youth who are current or former cigarette smokers, have tried marijuana or alcohol, were more likely to use bidi or hookah. Conclusions: Results suggest bidi and hookah use may be an emerging issue in tobacco control among youth. Findings also support an integrated approach where future prevention efforts should address multiple risk behaviors. 䉷 2011 Society for Adolescent Health and Medicine. All rights reserved.
Bidi (also known as beedi or beeri) is a hand-rolled, unfiltered cigarette of tobacco in tendu leaf [1], and hookah (also known as shisha, hubble-bubble, or nargile) is a water pipe that is used for smoking tobacco [2]. In Canada, both of these alternative tobacco products have become more accessible and represent affordable tobacco alternatives in a variety of flavors that appeal to youth. Recent studies have identified that the prevalence of bidi and hookah use has increased in North America, especially among youth [3,4]. This is a cause for concern as bidi and hookah contain many of the same harmful toxicants as cigarettes, such as tar, nicotine, and carbon monoxide [1,5]. Moreover, research has suggested that bidi and hookah users are at increased risk for some cancers and cardiovascular disease [1,5]. Considering that additional research on this emerging public health issue is required, the current study examined bidi and hookah use and behavior among Canadian youth.
* Address correspondence to: Scott T. Leatherdale, Ph.D., Department of Prevention and Cancer Control, Cancer Care Ontario, 620 University Avenue, Toronto, Ontario, Canada, M5G 2L7. E-mail address: [email protected] (S.T. Leatherdale).
Methods This study used nationally representative data collected from 41,886 students in grades 7–12 as part of the 2006 –2007 Canadian Youth Smoking Survey (YSS). Detailed information on the sample design, survey rates, and measures for the 2006 –2007 YSS is available on the YSS Web site (http://www.yss.uwaterloo. ca). In brief, the target population consisted of Canadian youth attending public and private elementary and secondary schools in 10 Canadian provinces. The YSS was administered to students during class time and participants were not provided compensation. Ever use of bidis or hookah was defined as those who have tried smoking bidis or using hookah to smoke tobacco. Current users of bidis or hookah were defined as those who have smoked bidis or used hookah to smoke tobacco in the last 30 days. Current smokers were defined as those who have smoked at least 100 cigarettes in his/her lifetime and have smoked in the 30 days preceding the survey. Former smokers were defined as those who smoked at least 100 cigarettes in his/her lifetime and had not smoked at all in the 30 days preceding the survey. Nonsmokers were defined as those who reported not having smoked 100 cigarettes in their lifetime and not having smoked in the 30 days
1054-139X/$ - see front matter 䉷 2011 Society for Adolescent Health and Medicine. All rights reserved. doi:10.1016/j.jadohealth.2010.11.250
W.C. Chan et al. / Journal of Adolescent Health 49 (2011) 102–104
Table 1 Descriptive analyses of bidi and hookah use among youth in grades 7–12, Canada 2006 Sample characteristic
Prevalence (%)a Ever use of Current use Ever use of Current use bidis of bidis hookah of hookah
All students Grade level 7th 8th 9th 10th 11th 12th Gender Male Female Provinceb Atlantic Canadac Quebec Ontario Prairiesd British Columbia Cigarette smoking status Nonsmoker Former smoker Current smoker Ever tried marijuana Yes No Ever tried alcohol Yes No a b
c
d e
1.7
.7
6.8
2.7
.4 .8 1.7 2.1 3.3 1.7
.3 .4 .9 .7 1.2 .5
1.0 3.2 5.0 8.6 11.8 12.1
.5 1.1 2.3 3.4 4.3 5.0
2.1 1.2
.9 .4
8.1 5.5
3.6 1.8
1.9 3.5 1.0 .8 2.4
.8 1.0 .5 .4 1.0
4.0 10.5 5.6 4.8 10.0
2.0 3.9 2.3 2.0 3.9
.8 8.9 11.0
.2 e 5.6
4.7 22.1 30.7
1.5 4.8 17.9
5.0 .2
1.8 .1
18.9 1.8
8.0 .5
2.3 .2
.8 .2
9.4 1.0
3.7 .6
Analyses were conducted by using weighted data. It is illegal to sell or give tobacco to anyone under the age of 18 in the provinces of Alberta, Manitoba, Quebec, and Saskatchewan, and under the age of 19 in the provinces of British Columbia, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, and Prince Edward Island. Atlantic Canada (New Brunswick, Prince Edward Island, Nova Scotia, Newfoundland and Labrador). Prairies (Alberta, Saskatchewan, Manitoba). Data were suppressed because of the unweighted sample size being less than 30.
103
preceding the survey. Ever use of alcohol or marijuana was defined as those who have had a drink of alcohol or tried marijuana. Descriptive analyses of bidis and hookah use were performed according to grade, sex, province, smoking status, marijuana use, and alcohol use. For the descriptive analyses, survey weights were used to adjust for nonresponse between provinces and groups, thereby minimizing any bias in the analyses caused by differential response rates across regions or groups. Four logistic regression models were used to examine factors associated with ever use of bidis (Model 1), current use of bidis (Model 2), ever use of hookah (Model 3), and current use of hookah (Model 4). The statistical package SAS 8.02 (Cary, NC) was used for all analyses. Results Descriptive analyses results are presented in Table 1. Students reported using bidi and hookah, although rates of ever and current hookah use are higher than ever or current use of bidis. Male youth and youth in higher grades were more likely to use bidi or hookah. The prevalence of hookah or bidi use was higher among youth who are current or former smokers, and youth who have ever used marijuana or alcohol. Results of the logistic regression analyses are presented in Table 2. Male youth were more likely to report ever and current use of bidis and hookah compared with female youth. Current or former smokers and youth who have tried marijuana were more likely to have ever tried bidi or hookah, and were also more likely to be current bidi or hookah users. Youth who have tried alcohol were more likely to have ever smoked a bidi or used hookah, but less likely to be current bidi users. Discussion We identified that youth who are current or former smokers were more likely to use or have used bidi or hookah compared with nonsmokers, and those who had tried marijuana were more likely to use or have used bidi or hookah. These findings are consistent with existing research [3,4]. We also identified that youth who have tried alcohol were also more likely to have tried
Table 2 Logistic regression analyses examining factors associated with bidi and hookah use among youth in grades 7–12, Canada 2006 Parameters
Sex Smoking status
Ever used marijuana Ever drank alcohol
Adjusted odds ratioa (95% CI) Coding
Model 1 ever use of bidis
Model 2 current use of bidis
Model 3 ever use of hookah
Model 4 current use of hookah
Female Male Non-smoker Former smoker Current smoker No Yes No Yes c statistic
1.0 1.7 (1.5–1.9)*** 1.0 4.9 (3.6–6.6)*** 5.1 (4.4–5.9)*** 1.0 9.0 (6.9–11.7)*** 1.0 1.7 (1.1–2.7)* .882
1.0 2.1 (1.7–2.7)*** 1.0 4.6 (2.4–8.7)* 12.4 (9.4–16.4)*** 1.0 6.2 (4.0–9.7)*** 1.0 .7 (.4–1.1)* .877
1.0 1.4 (1.3–1.5)*** 1.0 2.4 (1.9–2.9)** 3.0 (2.8–3.3)*** 1.0 5.4 (4.9–5.9)*** 1.0 2.3 (1.9–2.7)*** .868
1.0 1.9 (1.7–2.1)*** 1.0 1.4 (1.0–2.0)** 5.1 (4.6–5.8)*** 1.0 6.9 (5.7–8.3)*** 1.0 1.0 (.7–1.2)* .876
Model 1: 1 ⫽ yes (n ⫽ 964), 0 ⫽ not stated (n ⫽ 57,389). Model 2: 1 ⫽ yes (n ⫽ 380), 0 ⫽ not stated (n ⫽ 57,973). Model 3: 1 ⫽ yes (n ⫽ 3,988), 0 ⫽ not stated (n ⫽ 54,365). Model 4: 1 ⫽ yes (n ⫽ 1,595), 0 ⫽ not stated (n ⫽ 56,758). a Odds ratios adjusted for all other variables in the table and controlling for grade and province. * p ⬍ .05, ** p ⬍ .01, *** p ⬍ .001.
104
W.C. Chan et al. / Journal of Adolescent Health 49 (2011) 102–104
bidi or hookah. The comorbid use of these substances is consistent with research that has previously identified the clustering of marijuana, alcohol, and tobacco among Canadian youth [6] and further highlights the importance of implementing co-morbid substance use prevention programs in schools [7]. A common ethos in school-based prevention programming is to focus prevention activities on reducing the uptake of one substance, with the goal of reducing its prevalence of use rather than focusing on preventing substance use more globally [8]. Our data provide evidence to support the integration of school-based prevention efforts for multiple risk behaviors that are related and to commence such programs no later than elementary school, which is consistent with recommendations made by recent studies [9]. This study has several limitations common to survey research. Although the response rate was high and the data were weighted to help account for nonresponse, the findings are nevertheless subject to sample bias. In addition, the findings likely reflect some underreporting for substance use as is common in survey research [10]. The cross-sectional nature of the data does not allow for causal inferences regarding the association between bidi and hookah use and the correlates examined. Longitudinal data are required to determine the temporal sequence of the associations examined. Future research on bidi and hookah use is warranted. Developing a better understanding of the prevalence of bidi and hookah use, and factors associated with their use among youth is important because it can provide insight to guide the provision and timing of prevention interventions. Our results not only demonstrate for the first time the scope of this emerging issue within Canada, but also address gaps in current literature on the factors associated with bidi and hookah use. Acknowledgments The authors thank the Propel Centre for Population Health Impact and the Interdisciplinary Capacity Enhancement Pro-
gram at the University of Waterloo for providing support for this project. Dr Leatherdale is a Cancer Care Ontario Research Chair in Population Studies. The 2006 –2007 Youth Smoking Survey is a product of a pan-Canadian capacity building project that includes Canadian tobacco control researchers from all provinces and provides training opportunities for university students at all levels. The article has been made possible through a financial contribution from Health Canada. The views expressed herein do not necessarily represent the views of Health Canada. References [1] Rahman M, Fukui T. Bidi smoking and health. Public Health 2000;114: 123–7. [2] Dugas E, Tremblay M, Low NC, et al. Water-pipe smoking among North American youths. Pediatrics 2010;125:1184 –9. [3] Barnett TE, Curbow BA, Weitz JR, et al. Water pipe tobacco smoking among middle and high school students. Am J Public Health 2009;99: 2014 –19. [4] Delnevo CD, Pevzner ES, Hrywna M, Lewis MJ. Bidi cigarette use among young adults in 15 states. Prev Med 2004;39:207–11. [5] Eissenberg T, Shihadeh A. Waterpipe tobacco and cigarette smoking: Direct comparison of toxicant exposure. Am J Prev Med 2009;37:518 – 23. [6] Leatherdale ST, Hammond D, Ahmed R. Alcohol, marijuana, and tobacco use patterns among youth in Canada. Cancer Causes Control 2008;19: 361–9. [7] Ringwalt C, Hanley S, Vincus AA, et al. The prevalence of effective substance use prevention curricula in the nation’s high schools. J Prim Prev 2008;29: 479 – 88. [8] Poulin C, Elliott D. Alcohol, tobacco and cannabis use among Nova Scotia adolescents: Implications for prevention and harm reduction. CMAJ 1997; 156:1387–93. [9] Camenga DR, Klein JD, Roy J. The changing risk profile of the American adolescent smoker: Implications for prevention programs and tobacco interventions. J Adolesc Health 2006;39:120.e1–10. [10] Bovet P, Viswanathan B, Faeh D, Warren W. Comparison of smoking, drinking, and marijuana use between students present or absent on the day of a school-based survey. J Sch Health 2006;76:133–7.