Nicotine & Tobacco Research, Volume 16, Number 6 (June 2014) 709–716
Original Investigation
Sustained Waterpipe Use Among Young Adults Erika N. Dugas MSc1, Erin K. O’Loughlin MA1,2, Nancy C. Low MD, MSc3, Robert J. Wellman PhD4, Jennifer L. O’Loughlin PhD1,5,6 1Centre de Recherche du Centre Hospitalier de l’Université de Montréal; Montreal, Québec, Canada; 2Department of Exercise Science, Concordia University, Montreal, Québec, Canada; 3Department of Psychiatry, McGill University, Montreal, Québec, Canada; 4Department of Family Medicine and Community Health, University of Massachusetts Medical School, Worcester, MA; 5Department of Social and Preventive Medicine, University of Montréal, Montreal, Québec, Canada; 6Institut National de Santé Publique du Québec, Montreal, Québec, Canada
Corresponding Author: Jennifer O’Loughlin, PhD, CRCHUM, 850 Saint-Denis, S02-370, Montreal, Québec, H2X 0A9, Canada. Telephone: 514-890-8000, ext. 15858; Fax: 514-412-7137; E-mail: [email protected] Received July 3, 2013; accepted November 26, 2013
Introduction: Waterpipe smoking is increasingly popular among North American youth. However, the extent to which waterpipe use is sustained over time is not known. The objective of this study was to describe the frequency and the predictors of sustained waterpipe use over 4 years among young adults. Methods: Data were available in a prospective cohort investigation of 1,293 seventh-grade students recruited in a convenience sample of 10 secondary schools in Montreal, Canada, in 1999. Data on past-year waterpipe use were collected from 777 participants when they were age 20 years on average (in 2007–2008) and again when they were age 24 years (in 2011–2012) in mailed self-report questionnaires. Twenty potential predictors of sustained waterpipe use were tested, each in a separate multivariable logistic regression model. Results: About 51% of 182 waterpipe users at age 20 reported waterpipe use 4 years later. Most sustained users (88%) smoked a waterpipe less than once a month. Parental smoking, being currently employed, less frequent cigarette smoking, and more frequent marijuana use were associated with sustained waterpipe use. Conclusions: Half of the young adults who used waterpipe during young adulthood reported use 4 years later. Young adults who sustain waterpipe use appear to do so as an activity undertaken occasionally to socialize with others.
Introduction Waterpipe tobacco smoking, also known as hookah, shisha, goza, narghile, and hubble bubble (Maziak, Ward, Afifi Soweid, & Eissenberg, 2004), may represent the next global tobacco epidemic (Maziak, 2011). In 2012, the Canadian Tobacco Use Monitoring Survey (CTUMS) reported that 13% and 28% of adolescents and young adults, respectively, had used waterpipe—more than a twofold increase over the 6% and 11% reported in 2006 (Statistics Canada, 2012). Similarly, between 2009 and 2010 the lifetime prevalence of waterpipe use increased from 29% to 45% in female college students in the United States (Fielder, Carey, & Carey, 2012a). Low cost, easy access, the appeal of the social interaction associated with waterpipe use, and the perception that addictiveness and health risks are low likely underpin this growing popularity (Dugas, Tremblay, Low, Cournoyer, & O’Loughlin, 2010). Waterpipe is often perceived as “healthier” than cigarette smoking (Sutfin et al., 2011). However, waterpipe sessions typically last about 1 h and involve approximately 180 puffs with average puff volumes exceeding 500 ml, thereby exposing
waterpipe users to relatively large amounts of smoke (Cobb, Ward, Maziak, Shihadeh, & Eissenberg, 2010). Similar to cigarette smoke, waterpipe smoke contains substances that are harmful to health including carbon monoxide, carcinogens, and nicotine (Cobb, Shihadeh, Weaver, & Eissenberg, 2011; Shihadeh et al., 2012). Indeed, waterpipe smoking is associated with lung cancer, respiratory illness, low birth weight, and periodontal disease (Akl et al., 2010). Even if they contain no or low quantities of nicotine, waterpipe products labeled “tobacco-free” are a concern since they can contain substantial quantities of other toxic constituents such as polycyclic aromatic hydrocarbons and volatile aldehydes (Shihadeh et al., 2012). Further, secondhand waterpipe smoke may be hazardous due to the fine particulate matter present in the smoke (Cobb et al., 2010) which gradually builds up in the air reaching high levels that are comparable to those attained, although more rapidly, by cigarette smoking (Maziak, Rastam, Ibrahim, Ward, & Eissenberg, 2008). Because most studies on waterpipe to date are cross-sectional, the extent to which waterpipe use is sustained over time is not known. In the only longitudinal study reported to
doi:10.1093/ntr/ntt215 Advance Access publication December 30, 2013 © The Author 2013. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: [email protected].
709
Downloaded from http://ntr.oxfordjournals.org/ at University of Connecticut on May 10, 2015
Abstract
Sustained waterpipe use date, Fielder, Carey, and Carey (2012b) found that impulsivity, social comparison orientation (i.e., the extent to which a person compares himself to others), and marijuana use were associated with frequency of waterpipe use over 1 year in female college students in the United States. Overall therefore, little is known about whether waterpipe smokers sustain this behavior over time such that there is long-term exposure to the risks associated with waterpipe use. In addition, data on the patterns of use among sustained users are needed to better understand exposure. The objectives of this study were: (a) to describe the frequency and predictors of sustained waterpipe use over 4 years in young adults; and (b) to describe patterns of waterpipe use among sustained users.
Methods
Study Variables Frequency of past-year waterpipe use was measured in both 2007–2008 and 2011–2012 by: “In the past 12 months, how often did you use a waterpipe (hubble bubble, nargilé, shisha)?” Response choices included: never; less than once a month; 1–3 times per month; 1–6 times per week; and every day. Participants were identified as sustained users if they reported past-year waterpipe use in both surveys. Because the frequency of waterpipe use was low, participants were grouped according to whether or not they had used waterpipe in the past year for multivariable analyses. Lifetime waterpipe use (yes/no) was assessed in 2011–2012 by “Have you ever in your life used a waterpipe (hubble bubble, nargilé, shisha)?” Among lifetime users, age of waterpipe use onset, and other waterpipe-related behaviors were collected from lifetime users in 2011–2012 only. Waterpipe session duration was measured by: “When you use a waterpipe, how long does each waterpipe session usually last?” Response choices included less than 1, 1–2, or >2 h. Frequency of use in different settings was measured by: “How often do you use a waterpipe…” (a) alone; (b) in your home; (c) at a café or restaurant; (d) at a friend’s house; and (e) sharing the waterpipe hose with other people (never, rarely, sometimes, often).
710
Data Analysis A subset of participants (n = 182) who reported using waterpipe in 2007–2008 and who had data available in 2011–2012 was retained. After descriptive and univariate analyses, multivariable logistic regression models were conducted to test each potential predictor in a separate model with its own distinct set of covariates (i.e., each model addressed a specific hypothesis and consisted of an analysis within which only two tests were performed [univariate and multivariate]) (Bender & Lange, 2001). Potential confounders of the association under investigation in each model were identified in a correlation matrix, as those variables that were correlated with the potential predictor of interest at r ≥ .20. However, since age and sex have consistently been associated with waterpipe use in both Canada (Dugas et al., 2010; Czoli, Leatherdale, & Rynard, 2013) and the United States (Barnett, Curbow, Weitz, Johnson, & Smith-Simone, 2009; Smith-Simone, Curbow, & Stillman, 2008b; Ward et al., 2007; Jamil et al., 2010; Jarrett et al., 2012; Sterling & Mermelstein, 2011), all multivariable models were adjusted for sex and age regardless of their correlation with the potential predictor of interest. We used generalized estimating equations models (GEE) with an exchangeable correlation structure to take any correlation induced by sampling by school into account. All analyses were conducted using SPSS software, Version 16.0 (SPSS Inc., Chicago, IL) and STATA, version 12 (StataCorp. 2011. Stata Statistical Software: Release 12. College Station, TX: StataCorp LP.).
Results Of 878 NDIT participants with waterpipe data in 2007–2008 (68% of 1,293 participants at cohort inception), 792 (90%) completed questionnaires in 2011–2012. Fifteen participants had missing data on past-year waterpipe use in 2011–2012 so that the analytic sample included 777 participants. With
Downloaded from http://ntr.oxfordjournals.org/ at University of Connecticut on May 10, 2015
Data were drawn from the Nicotine Dependence in Teens (NDIT) Study, a prospective cohort investigation of 1,293 seventh-grade recruited in a convenience sample of 10 secondary schools in Montreal, Canada in 1999 (O’Loughlin, Karp, Koulis, Paradis, & Difranza, 2009). Self-report questionnaires were administered at school every 3 months during the 5 years of secondary school from grades 7 to 11, for a total of 20 survey cycles during secondary school. The present analysis uses data collected in mailed self-report questionnaires completed in 2007–2008 and 2011–2012 (survey cycles 21 and 22, respectively) when participants were age 20 and 24 years on average, respectively. Survey cycle 21 covered a median of 3.1 years post high school, and survey cycle 22 covered an additional 3.1 years after Survey 21. Parents/guardians provided written informed consent at baseline, and participants (who had attained legal age) provided consent in the post-high school survey cycles. The study was approved by the McGill University Institutional Review Board and the Ethics Research Committee of the Centre de Recherche du Centre Hospitalier de l’Université de Montréal.
Where participants obtained the (tobacco) product used in the waterpipe was measured by: “Do you buy tobacco for the waterpipe…” (a) on the internet; (b) in a tobacco shop; (c) at a convenience store; and (d) other (never, rarely, sometimes, often). Perception of harmfulness and addictiveness of waterpipe smoke compared to cigarette smoke (strongly agree, agree, disagree, strongly disagree) were also measured in 2011–2012 by: “Compared to smoking cigarettes, smoking a waterpipe is…” (a) less harmful and (b) less addictive. Potential predictors of sustained waterpipe use were selected based on factors associated with waterpipe use in existing studies on youth waterpipe smoking (Dugas et al., 2010; Eissenberg, Ward, Smith-Simone, & Maziak, 2008; Fielder et al., 2012b; Jamil, Elsouhag, Hiller, Arnetz, & Arnetz, 2010; Jarrett, Blosnich, Tworek, & Horn, 2012; Primack, Land, Fan, Kim, & Rosen, 2013; Primack, Walsh, Bryce, & Eissenberg, 2009; Primack et al., 2008; Smith et al., 2011; Smith-Simone, Maziak, Ward, & Eissenberg, 2008a; Sterling & Mermelstein, 2011; Sutfin et al., 2011; Ward et al., 2007). Potential predictors included sociodemographic, lifestyle, and health-related characteristics. Supplementary Appendix I describes these variables in detail including the specific measurement items, response choices, and how response choices were coded for analysis.
Nicotine & Tobacco Research
Discussion In 2011–2012, more than half of NDIT participants reported lifetime waterpipe use. This is more than double the prevalence reported for 20- to 24-year-olds in CTUMS in 2011 (Statistics Canada, 2011), but consistent with other recent reports (Fielder et al., 2012a; Sterling & Mermelstein, 2011; Sutfin et al., 2011). In this current analysis, half (51%) of those who reported use in 2007–2008 reported use four years later. This proportion is similar to or lower than that for other substances used during the same time period: 77% of NDIT participants who smoked cigarettes in 2007–2008 reported cigarette smoking in 2011– 2012; 76% sustained marijuana use, 56% sustained illicit drug use, 52% sustained use of tobacco products other than cigarettes; and 85% sustained binge drinking. Among ever users, 15% initiated waterpipe use before age 16, 29% initiated between age 16 and 17, 41% initiated between age 18 and 20 and 15% initiated after age 20. Therefore, 56% of youth who initiated waterpipe did so after high school and almost half initiated during the period just after high school, which may represent a critical window of opportunity for prevention. Although few studies to date investigate waterpipe-specific dependence measures, several reports argue that the presence of nicotine in waterpipe smoke elevates the risk of dependence (Cobb et al., 2011; Fagerström, & Eissenberg, 2012). Other cite symptoms reported by waterpipe users as evidence of possible nicotine dependence, including the similarity in subjective responses (i.e., pleasant, satisfying, tastes good) between waterpipe and cigarette smoking (Cobb et al., 2011), the presence of withdrawal symptoms in abstinent daily waterpipe users (Fagerström, & Eissenberg, 2012; Ward et al., 2007), the presence of cravings among regular waterpipe users (Jackson, & Aveyard, 2008) and the fact that waterpipe users make unsuccessful quit attempts (Ward et al., 2005). While waterpipe smoking may increase the risk of nicotine dependence, most sustained users in NDIT smoked waterpipe less than once a month, suggesting either that dependence is not an issue, or, if it is an issue, very infrequent use is enough to minimize cravings and withdrawal symptoms. Alternatively, many waterpipe users also smoked cigarettes and marijuana (possibly mixed with tobacco) which may reduce the need for nicotine consumed from waterpipe.
Table 1. Comparison of Selected Characteristics and Waterpipe Use Frequency in 2007–2008 of Study Participants With and Without Follow-Up Data in 2011–2012; NDIT Study 2012 Participants
Age at cohort inception, mean (SD) Male (%) French speaking (%) Mother university educated (%) Canadian born (%) Frequency of waterpipe use in 2007–2008 (%) Never
Original Investigation
Sustained Waterpipe Use Among Young Adults Erika N. Dugas MSc1, Erin K. O’Loughlin MA1,2, Nancy C. Low MD, MSc3, Robert J. Wellman PhD4, Jennifer L. O’Loughlin PhD1,5,6 1Centre de Recherche du Centre Hospitalier de l’Université de Montréal; Montreal, Québec, Canada; 2Department of Exercise Science, Concordia University, Montreal, Québec, Canada; 3Department of Psychiatry, McGill University, Montreal, Québec, Canada; 4Department of Family Medicine and Community Health, University of Massachusetts Medical School, Worcester, MA; 5Department of Social and Preventive Medicine, University of Montréal, Montreal, Québec, Canada; 6Institut National de Santé Publique du Québec, Montreal, Québec, Canada
Corresponding Author: Jennifer O’Loughlin, PhD, CRCHUM, 850 Saint-Denis, S02-370, Montreal, Québec, H2X 0A9, Canada. Telephone: 514-890-8000, ext. 15858; Fax: 514-412-7137; E-mail: [email protected] Received July 3, 2013; accepted November 26, 2013
Introduction: Waterpipe smoking is increasingly popular among North American youth. However, the extent to which waterpipe use is sustained over time is not known. The objective of this study was to describe the frequency and the predictors of sustained waterpipe use over 4 years among young adults. Methods: Data were available in a prospective cohort investigation of 1,293 seventh-grade students recruited in a convenience sample of 10 secondary schools in Montreal, Canada, in 1999. Data on past-year waterpipe use were collected from 777 participants when they were age 20 years on average (in 2007–2008) and again when they were age 24 years (in 2011–2012) in mailed self-report questionnaires. Twenty potential predictors of sustained waterpipe use were tested, each in a separate multivariable logistic regression model. Results: About 51% of 182 waterpipe users at age 20 reported waterpipe use 4 years later. Most sustained users (88%) smoked a waterpipe less than once a month. Parental smoking, being currently employed, less frequent cigarette smoking, and more frequent marijuana use were associated with sustained waterpipe use. Conclusions: Half of the young adults who used waterpipe during young adulthood reported use 4 years later. Young adults who sustain waterpipe use appear to do so as an activity undertaken occasionally to socialize with others.
Introduction Waterpipe tobacco smoking, also known as hookah, shisha, goza, narghile, and hubble bubble (Maziak, Ward, Afifi Soweid, & Eissenberg, 2004), may represent the next global tobacco epidemic (Maziak, 2011). In 2012, the Canadian Tobacco Use Monitoring Survey (CTUMS) reported that 13% and 28% of adolescents and young adults, respectively, had used waterpipe—more than a twofold increase over the 6% and 11% reported in 2006 (Statistics Canada, 2012). Similarly, between 2009 and 2010 the lifetime prevalence of waterpipe use increased from 29% to 45% in female college students in the United States (Fielder, Carey, & Carey, 2012a). Low cost, easy access, the appeal of the social interaction associated with waterpipe use, and the perception that addictiveness and health risks are low likely underpin this growing popularity (Dugas, Tremblay, Low, Cournoyer, & O’Loughlin, 2010). Waterpipe is often perceived as “healthier” than cigarette smoking (Sutfin et al., 2011). However, waterpipe sessions typically last about 1 h and involve approximately 180 puffs with average puff volumes exceeding 500 ml, thereby exposing
waterpipe users to relatively large amounts of smoke (Cobb, Ward, Maziak, Shihadeh, & Eissenberg, 2010). Similar to cigarette smoke, waterpipe smoke contains substances that are harmful to health including carbon monoxide, carcinogens, and nicotine (Cobb, Shihadeh, Weaver, & Eissenberg, 2011; Shihadeh et al., 2012). Indeed, waterpipe smoking is associated with lung cancer, respiratory illness, low birth weight, and periodontal disease (Akl et al., 2010). Even if they contain no or low quantities of nicotine, waterpipe products labeled “tobacco-free” are a concern since they can contain substantial quantities of other toxic constituents such as polycyclic aromatic hydrocarbons and volatile aldehydes (Shihadeh et al., 2012). Further, secondhand waterpipe smoke may be hazardous due to the fine particulate matter present in the smoke (Cobb et al., 2010) which gradually builds up in the air reaching high levels that are comparable to those attained, although more rapidly, by cigarette smoking (Maziak, Rastam, Ibrahim, Ward, & Eissenberg, 2008). Because most studies on waterpipe to date are cross-sectional, the extent to which waterpipe use is sustained over time is not known. In the only longitudinal study reported to
doi:10.1093/ntr/ntt215 Advance Access publication December 30, 2013 © The Author 2013. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: [email protected].
709
Downloaded from http://ntr.oxfordjournals.org/ at University of Connecticut on May 10, 2015
Abstract
Sustained waterpipe use date, Fielder, Carey, and Carey (2012b) found that impulsivity, social comparison orientation (i.e., the extent to which a person compares himself to others), and marijuana use were associated with frequency of waterpipe use over 1 year in female college students in the United States. Overall therefore, little is known about whether waterpipe smokers sustain this behavior over time such that there is long-term exposure to the risks associated with waterpipe use. In addition, data on the patterns of use among sustained users are needed to better understand exposure. The objectives of this study were: (a) to describe the frequency and predictors of sustained waterpipe use over 4 years in young adults; and (b) to describe patterns of waterpipe use among sustained users.
Methods
Study Variables Frequency of past-year waterpipe use was measured in both 2007–2008 and 2011–2012 by: “In the past 12 months, how often did you use a waterpipe (hubble bubble, nargilé, shisha)?” Response choices included: never; less than once a month; 1–3 times per month; 1–6 times per week; and every day. Participants were identified as sustained users if they reported past-year waterpipe use in both surveys. Because the frequency of waterpipe use was low, participants were grouped according to whether or not they had used waterpipe in the past year for multivariable analyses. Lifetime waterpipe use (yes/no) was assessed in 2011–2012 by “Have you ever in your life used a waterpipe (hubble bubble, nargilé, shisha)?” Among lifetime users, age of waterpipe use onset, and other waterpipe-related behaviors were collected from lifetime users in 2011–2012 only. Waterpipe session duration was measured by: “When you use a waterpipe, how long does each waterpipe session usually last?” Response choices included less than 1, 1–2, or >2 h. Frequency of use in different settings was measured by: “How often do you use a waterpipe…” (a) alone; (b) in your home; (c) at a café or restaurant; (d) at a friend’s house; and (e) sharing the waterpipe hose with other people (never, rarely, sometimes, often).
710
Data Analysis A subset of participants (n = 182) who reported using waterpipe in 2007–2008 and who had data available in 2011–2012 was retained. After descriptive and univariate analyses, multivariable logistic regression models were conducted to test each potential predictor in a separate model with its own distinct set of covariates (i.e., each model addressed a specific hypothesis and consisted of an analysis within which only two tests were performed [univariate and multivariate]) (Bender & Lange, 2001). Potential confounders of the association under investigation in each model were identified in a correlation matrix, as those variables that were correlated with the potential predictor of interest at r ≥ .20. However, since age and sex have consistently been associated with waterpipe use in both Canada (Dugas et al., 2010; Czoli, Leatherdale, & Rynard, 2013) and the United States (Barnett, Curbow, Weitz, Johnson, & Smith-Simone, 2009; Smith-Simone, Curbow, & Stillman, 2008b; Ward et al., 2007; Jamil et al., 2010; Jarrett et al., 2012; Sterling & Mermelstein, 2011), all multivariable models were adjusted for sex and age regardless of their correlation with the potential predictor of interest. We used generalized estimating equations models (GEE) with an exchangeable correlation structure to take any correlation induced by sampling by school into account. All analyses were conducted using SPSS software, Version 16.0 (SPSS Inc., Chicago, IL) and STATA, version 12 (StataCorp. 2011. Stata Statistical Software: Release 12. College Station, TX: StataCorp LP.).
Results Of 878 NDIT participants with waterpipe data in 2007–2008 (68% of 1,293 participants at cohort inception), 792 (90%) completed questionnaires in 2011–2012. Fifteen participants had missing data on past-year waterpipe use in 2011–2012 so that the analytic sample included 777 participants. With
Downloaded from http://ntr.oxfordjournals.org/ at University of Connecticut on May 10, 2015
Data were drawn from the Nicotine Dependence in Teens (NDIT) Study, a prospective cohort investigation of 1,293 seventh-grade recruited in a convenience sample of 10 secondary schools in Montreal, Canada in 1999 (O’Loughlin, Karp, Koulis, Paradis, & Difranza, 2009). Self-report questionnaires were administered at school every 3 months during the 5 years of secondary school from grades 7 to 11, for a total of 20 survey cycles during secondary school. The present analysis uses data collected in mailed self-report questionnaires completed in 2007–2008 and 2011–2012 (survey cycles 21 and 22, respectively) when participants were age 20 and 24 years on average, respectively. Survey cycle 21 covered a median of 3.1 years post high school, and survey cycle 22 covered an additional 3.1 years after Survey 21. Parents/guardians provided written informed consent at baseline, and participants (who had attained legal age) provided consent in the post-high school survey cycles. The study was approved by the McGill University Institutional Review Board and the Ethics Research Committee of the Centre de Recherche du Centre Hospitalier de l’Université de Montréal.
Where participants obtained the (tobacco) product used in the waterpipe was measured by: “Do you buy tobacco for the waterpipe…” (a) on the internet; (b) in a tobacco shop; (c) at a convenience store; and (d) other (never, rarely, sometimes, often). Perception of harmfulness and addictiveness of waterpipe smoke compared to cigarette smoke (strongly agree, agree, disagree, strongly disagree) were also measured in 2011–2012 by: “Compared to smoking cigarettes, smoking a waterpipe is…” (a) less harmful and (b) less addictive. Potential predictors of sustained waterpipe use were selected based on factors associated with waterpipe use in existing studies on youth waterpipe smoking (Dugas et al., 2010; Eissenberg, Ward, Smith-Simone, & Maziak, 2008; Fielder et al., 2012b; Jamil, Elsouhag, Hiller, Arnetz, & Arnetz, 2010; Jarrett, Blosnich, Tworek, & Horn, 2012; Primack, Land, Fan, Kim, & Rosen, 2013; Primack, Walsh, Bryce, & Eissenberg, 2009; Primack et al., 2008; Smith et al., 2011; Smith-Simone, Maziak, Ward, & Eissenberg, 2008a; Sterling & Mermelstein, 2011; Sutfin et al., 2011; Ward et al., 2007). Potential predictors included sociodemographic, lifestyle, and health-related characteristics. Supplementary Appendix I describes these variables in detail including the specific measurement items, response choices, and how response choices were coded for analysis.
Nicotine & Tobacco Research
Discussion In 2011–2012, more than half of NDIT participants reported lifetime waterpipe use. This is more than double the prevalence reported for 20- to 24-year-olds in CTUMS in 2011 (Statistics Canada, 2011), but consistent with other recent reports (Fielder et al., 2012a; Sterling & Mermelstein, 2011; Sutfin et al., 2011). In this current analysis, half (51%) of those who reported use in 2007–2008 reported use four years later. This proportion is similar to or lower than that for other substances used during the same time period: 77% of NDIT participants who smoked cigarettes in 2007–2008 reported cigarette smoking in 2011– 2012; 76% sustained marijuana use, 56% sustained illicit drug use, 52% sustained use of tobacco products other than cigarettes; and 85% sustained binge drinking. Among ever users, 15% initiated waterpipe use before age 16, 29% initiated between age 16 and 17, 41% initiated between age 18 and 20 and 15% initiated after age 20. Therefore, 56% of youth who initiated waterpipe did so after high school and almost half initiated during the period just after high school, which may represent a critical window of opportunity for prevention. Although few studies to date investigate waterpipe-specific dependence measures, several reports argue that the presence of nicotine in waterpipe smoke elevates the risk of dependence (Cobb et al., 2011; Fagerström, & Eissenberg, 2012). Other cite symptoms reported by waterpipe users as evidence of possible nicotine dependence, including the similarity in subjective responses (i.e., pleasant, satisfying, tastes good) between waterpipe and cigarette smoking (Cobb et al., 2011), the presence of withdrawal symptoms in abstinent daily waterpipe users (Fagerström, & Eissenberg, 2012; Ward et al., 2007), the presence of cravings among regular waterpipe users (Jackson, & Aveyard, 2008) and the fact that waterpipe users make unsuccessful quit attempts (Ward et al., 2005). While waterpipe smoking may increase the risk of nicotine dependence, most sustained users in NDIT smoked waterpipe less than once a month, suggesting either that dependence is not an issue, or, if it is an issue, very infrequent use is enough to minimize cravings and withdrawal symptoms. Alternatively, many waterpipe users also smoked cigarettes and marijuana (possibly mixed with tobacco) which may reduce the need for nicotine consumed from waterpipe.
Table 1. Comparison of Selected Characteristics and Waterpipe Use Frequency in 2007–2008 of Study Participants With and Without Follow-Up Data in 2011–2012; NDIT Study 2012 Participants
Age at cohort inception, mean (SD) Male (%) French speaking (%) Mother university educated (%) Canadian born (%) Frequency of waterpipe use in 2007–2008 (%) Never
