579414 research-article2015
HEBXXX10.1177/1090198115579414Health Education & BehaviorBlackstone and Herrmann
Brief Report
Relationships Between Illicit Drug Use and Body Mass Index Among Adolescents
Health Education & Behavior 1–4 © 2015 Society for Public Health Education Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1090198115579414 heb.sagepub.com
Sarah R. Blackstone, MPH1, and Lynn K. Herrmann, PhD, MPH1
Abstract Prior research has established associations between body mass index (BMI) and use of alcohol, tobacco, and marijuana. However, little research has been done investigating the relationship between other common illicit drugs and BMI trends. The present study investigated whether adolescents who reported using illicit drugs showed differences in BMI compared to peers who reported no drug use. There was a positive relationship between drug use and BMI as well as the number of drugs used and BMI. The results suggested that the positive relationship between the use of illicit drugs and BMI is largely due to smoking. Further research needs to ascertain whether smoking, illicit drug use, or both are among the first of many unhealthy behaviors that can subsequently lead to greater gains in BMI. Implications for health educators are discussed. Keywords adolescent health, health behavior, obesity, substance use
Adolescent risk behaviors are those that contribute to leading causes of morbidity and mortality in youth and adults. The Youth Risk Behavior Surveillance System defines six categories of risk behaviors: (a) behaviors that contribute to unintentional injuries and violence, (b) tobacco use, (c) alcohol and other drug use, (d) sexual behaviors that contribute to unintended pregnancy and sexually transmitted infections, (e) unhealthy dietary behaviors, and (f) physical inactivity (Eaton et al., 2012). Of these risk behaviors, poor diet, physical inactivity, alcohol, and tobacco use are thought to be associated with higher body mass index (BMI) trajectory across lifespan (Huang, Lanza, Wright-Volel, & Anglin, 2013; Pasch, Nelson, Lytle, Moe, & Perry, 2008). BMI, a measure of body fat based on height and weight, is used to screen for weight categories that are associated with health problems. Since BMI is related to chronic diseases later in life, it is important to begin monitoring at a young age, as its trajectory can be influenced by behaviors developed earlier in life (Centers for Disease Control and Prevention, 2014). According to one study, as many as 39% of high school seniors reported drinking alcohol and smoking tobacco in the past 30 days (Johnston, O’Malley, Miech, Bachman, & Schulenberg, 2013). Previous research has provided conflicting information regarding the associations between these behaviors and weight. For instance, Huang et al. (2013) found that consumption of alcoholic beverages at age 14 was lower among those who were chronically obese as adults, and that those on the chronically obese trajectory were at an increased risk for tobacco use (e.g., cigarette smoking,
chewing tobacco) with age. Obesity in adolescence has also been shown to relate to increased tobacco use as adults. Pasch et al. (2008) investigated associations between use of alcohol, cigarettes, marijuana, and inhalants (referred to as Alcohol, Tobacco, and Other Drug [ATOD] use) in middle school students. In contrast to Huang et al. (2013), Pasch et al. (2008) found that binge drinking and ATOD use were positively associated with BMI. Longitudinal associations in the same study showed that greater use of ATOD at the beginning of seventh grade was associated with a higher BMI at the end of eighth grade. However, BMI at the beginning of seventh grade did not predict the adoption of risk or protective behaviors with regard to alcohol and tobacco at the end of students’ eighth grade year. Illicit drugs encompass a wide range of substances (e.g., cocaine, methamphetamine, ecstasy, etc.) and are used by approximately 25% of 12th-grade students (Johnston et al., 2013). In the present study, illicit substances refer to substances outside of tobacco, alcohol, and marijuana, which are used to recreationally alter one’s state of mind. Illicit substances are under international control but consumed illegally (National Institute on Drug Abuse, 2012). Despite the 1
Northern Illinois University, DeKalb, IL, USA
Corresponding Author: Sarah R. Blackstone, Northern Illinois University, College of Health and Human Sciences, Public Health and Health Education Programs, 209L Wirtz Hall, DeKalb, IL 60115, USA. Email: [email protected]
2 array of studies examining the association between BMI and substance use, defined in this article as the use of any psychologically or physiologically altering substance used for recreation (including alcohol, tobacco, or illicit drugs), the current research, to date, has primarily focused on alcohol and tobacco. Few studies have investigated other illicit drugs’ relationships with BMI. Liu et al. (2010) discovered that among Taiwanese adolescents, there was no association between illicit drug use and BMI, while there were relationships between smoking, alcohol use, and BMI. Denoth, Siciliano, Iozzo, Fortunato, and Molinaro (2011) expanded on prior research and found higher usage of cannabis, cocaine, and dieting drugs in overweight adolescents. Because of the high prevalence of illicit drug use (e.g., narcotics, amphetamines, opiates, and other prescription drugs) in the United States, the lack of research examining the associations between these drugs and BMI creates a gap in the literature. The purpose of the present study is to address this gap by examining the relationship between illicit drug use and BMI in a nationally representative sample of adolescents. These results provide preliminary data in this area, as well as support the need for future research expanding investigations of substance use and BMI to include illicit drugs beyond alcohol and tobacco. Ultimately, this could affect health education programs for youth.
Method Data from the 2009-2010 Health Behavior in School AgedChildren Series were analyzed for the present study (Iannotti, 2013). The Health Behavior in School-Aged Children series is a collection of independent surveys of school-age children. These surveys are intended to monitor risk behaviors and attitudes in adolescents and provide relevant information regarding health attitudes and behaviors in adolescents. This study employed data solely from the United States, which are available for public access. Illicit drug use was measured by dichotomizing responses regarding frequency of use (e.g., “In the past 12 months how often have you used cocaine?”). The illicit drugs measured included ecstasy, amphetamines, opiates, prescription medications, inhalants, lysergic acid diethylamide, and anabolic steroids. The total number of drugs taken in the past year was computed by summing the number of drugs to which participants responded they had used. Only students in 10th grade (N = 1,907) were asked about illicit drug use. Associations between drug use and BMI were determined using linear regression. Alcohol use was measured by asking, “Do you drink alcohol presently?” Tobacco use was measured with the question, “Have you ever smoked tobacco?” Marijuana use was measured by asking, “Have you ever used marijuana?” Lifetime measures of alcohol and illicit drug use were not available, thus requiring measures from different time frames to be used. Students in Grades 6 to 10 were asked the previous questions regarding alcohol, tobacco, and marijuana. All responses were dichotomized.
Health Education & Behavior BMI was computed based on self-report height and weight, which has been shown as an acceptable measure in previous studies (Goodman, Hinden, & Khandelwal, 2000) and was treated as a linear response variable. Adjusted BMI weight categories were computed using the Centers for Disease Control and Prevention growth chart (Kuczmarski et al., 2002). Adjustment for gender, age, and race was done in this analysis.
Results A total of 10,925 students in Grades 6 to 10 participated, of which 51.4% were male and 48.6% were female, 18.3% were at risk of being overweight according to adjusted BMI, and 13.8% were overweight. The percentage of students consuming alcohol in the past 30 days was 25.1%. Illicit drug use in the past 12 months was 14.8% of the 1,907 10th graders asked, and the percentages of students who had smoked tobacco or marijuana at least once in their lifetime were 15.9% and 14.3%, respectively (see Table 1). Tobacco use and linear BMI were positively associated; those who used tobacco had higher BMI (p < .001), even after adjustment for demographics (e.g., gender, age, grade, race). After adjustment for demographics, alcohol consumption was not significantly associated with BMI. Overall, students who did not report using any illicit drug in the past 12 months had lower BMI than those who did (p < .05). The association between illicit drug use and BMI was not evident after adjustment for alcohol and tobacco use. Furthermore, we used statistical interaction to test whether the association between drug use and BMI differed in those who did and did not use tobacco and found no evidence that this was the case (p > .05). The number of drugs taken in the past 12 months was positively associated with BMI, even after adjustment for alcohol, tobacco, marijuana use (p < .05), and demographics. When each of the illicit drugs measured were tested as part of the equation, there were no significant relationships with BMI, which is possibly due to a limited sample of students who reported using each respective drug (see Table 2).
Discussion Despite the literature on BMI and substance use, there are limited data regarding the use of illicit drugs and the relationships with BMI in adolescents, thus creating a void in the literature. Though the results of the current study do not offer conclusive evidence, the data indicate a relationship between illicit drug use and BMI, which suggests the need for further investigation in this area. The number of illicit drugs used showed positive associations with BMI after adjustment for alcohol, tobacco, and demographic factors. Unadjusted associations between using illicit drugs and BMI were significant, though this effect disappeared after adjusting for tobacco and alcohol use. Because of the high correlations between smoking and drug use seen in bivariate analyses,
3
Blackstone and Herrmann Table 1. Descriptive Statistics. Variable Gender Male Female Grade 6th 7th 8th 9th 10th Race Black White Asian American Indian Pacific Islander 2+ Races Hispanic Adjusted body mass index Underweight Normal weight At risk of overweight Overweight Used tobacco Yes No Used marijuana Yes No Used alcohol Yes No Used drugs (10th grade) Yes No Illicit drugs (10th grade only) Ecstasy Amphetamines Opiates Prescription medicine Inhalants Lysergic acid diethylamide Steroids
n
Proportion
Table 2. Effects of Drug Use on Body Mass Index From Multiple Linear Regression. Overall drug use
Yes Yes Yes Yes Yes Yes Yes
5,629 5,293
51.4 48.6
2,050 2,421 2,475 2,072 1,907
18.8 22.2 22.7 18.5 17.8
2,090 5,698 455 210 105 794 2,312
17.9 48.8 3.9 1.8 0.9 6.8 19.8
394 5,839 1,680 1,276
4.3 63.6 18.3 13.8
1,679 8,731
15.9 84.1
1,488 8,881
14.3 85.7
7,770 3,343
74.9 25.1
258 1,489
14.8 85.2
57 28 11 76 43 17 8
3 1.5 0.6 4 2.3 0.9 0.4
educators may have success in targeting both illicit drug and smoking prevention simultaneously. Both may be important in obesity-prevention programs for youth as well. Though these results are not unexpected, this study is one of few specifically examining the broad range of “other drugs” and their relationship with BMI. These data are consistent with other studies, suggesting that tobacco use is associated with a risk of higher BMI trajectories in adolescents and adults (Barry & Petry, 2009; Huang et al., 2013; Pasch et al., 2008). Pasch et al. (2008)
Used drugs (yes/no) Alcohol Marijuana Tobacco Number of drugs Number of drugs taken Alcohol Tobacco Marijuana
B −.326a −.085a .288a −1.20*** B .350* −.768a −1.11a −.332a
a Reference = yes. *p < .05. ***p < .001.
posited that using tobacco in adolescence is a risk factor for developing unhealthy habits in adulthood, among which could be included those habits or behaviors affecting overweight and obesity. Results of their longitudinal study showed that it was not obese adolescents who were more prone to engage in risk behaviors (e.g., ATOD use), but that students already engaging in risk behaviors experienced greater gains in BMI. Due to the high prevalence of obesity in the United States, identifying early risk factors plays an important role in prevention initiatives. The fact that smoking was a confounding variable in the relationship between illicit drug use and BMI suggests that further research is needed to determine the interactions and temporal pathways between drug use, smoking, and BMI trajectory. Smoking, however, did not act as a confounding variable in the relationship between the number of illicit drugs used and BMI. There are limitations to this study. First, the cross-sectional design prohibits us from making any causal inferences about the time sequences regarding illicit drug use, tobacco use, and BMI. Second, we cannot determine whether relationships exist between individual illicit drugs and BMI due to limited sample size. More research with samples providing better statistical power needs to be conducted to better draw conclusions. Despite these limitations, this study, to our knowledge, is one of the first along with Denoth et al. (2011) to investigate this relationship. This study provides evidence of a positive association between the number of illicit drugs used and BMI, which suggests that illicit drugs should be further investigated in relation to BMI. Especially given the established trend between adolescent tobacco use and subsequent obesity, and the confounding effects of tobacco use in this study, it is important to determine whether using illicit drugs, smoking, or both in adolescence has a relationship with the development of health behaviors related to weight gain. By providing evidence of a relationship between illicit substances and BMI, this study offers deeper insight for
4 health educators regarding risk factors for obesity. It could be that illicit drug use is among the first of several unhealthy behaviors that adolescents, particularly smokers, engage in before adopting habits putting them at risk for obesity. If this is the case, overall healthy lifestyle choices should be emphasized in drug education in addition to avoiding drug using behavior, especially since adolescence is such a critical period of development. Past research has indicated that peer influence plays a critical role in the initiation of smoking behaviors (Kobus, 2003). Interventions based on Social Network Theory or the Theory of Planned Behavior may equip educators to address the peer and social influences that play a role in developing smoking and other drug-related behaviors. Broadly, better understanding the relationship between substance use and BMI can help educators and practitioners more quickly identify those at a high risk of adopting future unhealthy behaviors that could lead to obesity and associated chronic illness. Acknowledgments These data were obtained from the Inter-university Consortium for Political and Social Research, part of the Institute for Social Research at the University of Michigan. The Health Behavior in School Aged Children Series is sponsored by the National Institute of Child Health and Human Development.
Declaration of Conflicting Interests The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The authors received no financial support for the research, authorship, and/or publication of this article.
References Barry, D., & Petry, N. M. (2009). Associations between body mass index and substance use disorders differ by gender: Results from the national epidemiologic survey on alcohol and related conditions. Addictive Behaviors, 34, 51-60. doi:10.1016/j.addbeh.2008.08.008 Centers for Disease Control and Prevention. (2014). Body mass index. Retrieved from http://www.cdc.gov/healthyweight/ assessing/bmi/Index.html
Health Education & Behavior Denoth, F., Siciliano, V., Iozzo, P., Fortunato, L., & Molinaro, S. (2011). The association between overweight and illegal drug consumption in adolescents: Is there an underlying influence of the sociocultural environment? PLoS One, 6(11), e27358. doi:10.1371/journal.pone.0027358 Eaton, D. K., Kann, L., Kinchen, S., Shanklin, S., Flint, K. H., Hawkins, J., . . .Wechsler, H. (2012). Youth risk behavior surveillance—United States, 2011. Morbidity and Mortality Weekly Report. Surveillance Summaries (Washington, D.C.: 2002), 61(4), 1-162. Goodman, E., Hinden, B. R., & Khandelwal, S. (2000). Accuracy of teen and parental reports of obesity and body mass index. Pediatrics, 106(1 Pt 1), 52-58. Huang, D. Y. C., Lanza, H. I., Wright-Volel, K., & Anglin, M. D. (2013). Developmental trajectories of childhood obesity and risk behaviors in adolescence. Journal of Adolescence, 36, 139-148. doi:10.1016/j.adolescence.2012.10.005 Iannotti, R. J. (2013). Health Behavior in School-Aged Children (HBSC), 2009-2010: Version 1. Retrieved from https://www. icpsr.umich.edu/icpsrweb/NAHDAP/studies/34792?paging. startRow=1&q=%22mental+health%22&dataFormat%5B0% 5D=SDA&dataFormat%5B1%5D=R Johnston, L. D., O’Malley, P. M., Miech, R. A., Bachman, J. G., & Schulenberg, G. E. (2013). Monitoring the future—National results on drug use: 2013 Overview: Key findings on adolescent drug use. Retrieved from http://www.monitoringthefuture.org/pubs/monographs/mtf-overview2013.pdf Kobus, K. (2003). Peers and adolescent smoking. Addiction, 98(Suppl. 1), 37-55. Kuczmarski, R. J., Ogden, C. L., Guo, S. S., Grummer-Strawn, L. M., Flegal, K. M., Mei, Z., . . .Johnson, C. L. (2002). 2000 CDC growth charts for the United States: Methods and development. Vital Health Statistics, 11(246), 2002. Retrieved from http://www.cdc.gov/nchs/data/series/sr_11/sr11_246.pdf Liu, T. L., Yen, J. Y., Ko, C. H., Huang, M. F., Wang, P. W., Yeh, Y. C., & Yen, C. F. (2010). Associations between substance use and body mass index: Moderating effects of sociodemographic characteristics among Taiwanese adolescents. Kaohsiung Journal of Medical Sciences, 26, 281-289. doi:10.1016/S1607-551X(10)70041-3 National Institute on Drug Abuse. (2012). Drug facts: Inhalants. Retrieved from http://www.drugabuse.gov/publications/drugfacts/inhalants Pasch, K. E., Nelson, M. C., Lytle, L. A., Moe, S. G., & Perry, C. L. (2008). Adoption of risk-related factors through early adolescence: Associations with weight status and implications for causal mechanisms. Journal of Adolescent Health, 43, 387393. doi:10.1016/j.jadohealth.2008.02.009
HEBXXX10.1177/1090198115579414Health Education & BehaviorBlackstone and Herrmann
Brief Report
Relationships Between Illicit Drug Use and Body Mass Index Among Adolescents
Health Education & Behavior 1–4 © 2015 Society for Public Health Education Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1090198115579414 heb.sagepub.com
Sarah R. Blackstone, MPH1, and Lynn K. Herrmann, PhD, MPH1
Abstract Prior research has established associations between body mass index (BMI) and use of alcohol, tobacco, and marijuana. However, little research has been done investigating the relationship between other common illicit drugs and BMI trends. The present study investigated whether adolescents who reported using illicit drugs showed differences in BMI compared to peers who reported no drug use. There was a positive relationship between drug use and BMI as well as the number of drugs used and BMI. The results suggested that the positive relationship between the use of illicit drugs and BMI is largely due to smoking. Further research needs to ascertain whether smoking, illicit drug use, or both are among the first of many unhealthy behaviors that can subsequently lead to greater gains in BMI. Implications for health educators are discussed. Keywords adolescent health, health behavior, obesity, substance use
Adolescent risk behaviors are those that contribute to leading causes of morbidity and mortality in youth and adults. The Youth Risk Behavior Surveillance System defines six categories of risk behaviors: (a) behaviors that contribute to unintentional injuries and violence, (b) tobacco use, (c) alcohol and other drug use, (d) sexual behaviors that contribute to unintended pregnancy and sexually transmitted infections, (e) unhealthy dietary behaviors, and (f) physical inactivity (Eaton et al., 2012). Of these risk behaviors, poor diet, physical inactivity, alcohol, and tobacco use are thought to be associated with higher body mass index (BMI) trajectory across lifespan (Huang, Lanza, Wright-Volel, & Anglin, 2013; Pasch, Nelson, Lytle, Moe, & Perry, 2008). BMI, a measure of body fat based on height and weight, is used to screen for weight categories that are associated with health problems. Since BMI is related to chronic diseases later in life, it is important to begin monitoring at a young age, as its trajectory can be influenced by behaviors developed earlier in life (Centers for Disease Control and Prevention, 2014). According to one study, as many as 39% of high school seniors reported drinking alcohol and smoking tobacco in the past 30 days (Johnston, O’Malley, Miech, Bachman, & Schulenberg, 2013). Previous research has provided conflicting information regarding the associations between these behaviors and weight. For instance, Huang et al. (2013) found that consumption of alcoholic beverages at age 14 was lower among those who were chronically obese as adults, and that those on the chronically obese trajectory were at an increased risk for tobacco use (e.g., cigarette smoking,
chewing tobacco) with age. Obesity in adolescence has also been shown to relate to increased tobacco use as adults. Pasch et al. (2008) investigated associations between use of alcohol, cigarettes, marijuana, and inhalants (referred to as Alcohol, Tobacco, and Other Drug [ATOD] use) in middle school students. In contrast to Huang et al. (2013), Pasch et al. (2008) found that binge drinking and ATOD use were positively associated with BMI. Longitudinal associations in the same study showed that greater use of ATOD at the beginning of seventh grade was associated with a higher BMI at the end of eighth grade. However, BMI at the beginning of seventh grade did not predict the adoption of risk or protective behaviors with regard to alcohol and tobacco at the end of students’ eighth grade year. Illicit drugs encompass a wide range of substances (e.g., cocaine, methamphetamine, ecstasy, etc.) and are used by approximately 25% of 12th-grade students (Johnston et al., 2013). In the present study, illicit substances refer to substances outside of tobacco, alcohol, and marijuana, which are used to recreationally alter one’s state of mind. Illicit substances are under international control but consumed illegally (National Institute on Drug Abuse, 2012). Despite the 1
Northern Illinois University, DeKalb, IL, USA
Corresponding Author: Sarah R. Blackstone, Northern Illinois University, College of Health and Human Sciences, Public Health and Health Education Programs, 209L Wirtz Hall, DeKalb, IL 60115, USA. Email: [email protected]
2 array of studies examining the association between BMI and substance use, defined in this article as the use of any psychologically or physiologically altering substance used for recreation (including alcohol, tobacco, or illicit drugs), the current research, to date, has primarily focused on alcohol and tobacco. Few studies have investigated other illicit drugs’ relationships with BMI. Liu et al. (2010) discovered that among Taiwanese adolescents, there was no association between illicit drug use and BMI, while there were relationships between smoking, alcohol use, and BMI. Denoth, Siciliano, Iozzo, Fortunato, and Molinaro (2011) expanded on prior research and found higher usage of cannabis, cocaine, and dieting drugs in overweight adolescents. Because of the high prevalence of illicit drug use (e.g., narcotics, amphetamines, opiates, and other prescription drugs) in the United States, the lack of research examining the associations between these drugs and BMI creates a gap in the literature. The purpose of the present study is to address this gap by examining the relationship between illicit drug use and BMI in a nationally representative sample of adolescents. These results provide preliminary data in this area, as well as support the need for future research expanding investigations of substance use and BMI to include illicit drugs beyond alcohol and tobacco. Ultimately, this could affect health education programs for youth.
Method Data from the 2009-2010 Health Behavior in School AgedChildren Series were analyzed for the present study (Iannotti, 2013). The Health Behavior in School-Aged Children series is a collection of independent surveys of school-age children. These surveys are intended to monitor risk behaviors and attitudes in adolescents and provide relevant information regarding health attitudes and behaviors in adolescents. This study employed data solely from the United States, which are available for public access. Illicit drug use was measured by dichotomizing responses regarding frequency of use (e.g., “In the past 12 months how often have you used cocaine?”). The illicit drugs measured included ecstasy, amphetamines, opiates, prescription medications, inhalants, lysergic acid diethylamide, and anabolic steroids. The total number of drugs taken in the past year was computed by summing the number of drugs to which participants responded they had used. Only students in 10th grade (N = 1,907) were asked about illicit drug use. Associations between drug use and BMI were determined using linear regression. Alcohol use was measured by asking, “Do you drink alcohol presently?” Tobacco use was measured with the question, “Have you ever smoked tobacco?” Marijuana use was measured by asking, “Have you ever used marijuana?” Lifetime measures of alcohol and illicit drug use were not available, thus requiring measures from different time frames to be used. Students in Grades 6 to 10 were asked the previous questions regarding alcohol, tobacco, and marijuana. All responses were dichotomized.
Health Education & Behavior BMI was computed based on self-report height and weight, which has been shown as an acceptable measure in previous studies (Goodman, Hinden, & Khandelwal, 2000) and was treated as a linear response variable. Adjusted BMI weight categories were computed using the Centers for Disease Control and Prevention growth chart (Kuczmarski et al., 2002). Adjustment for gender, age, and race was done in this analysis.
Results A total of 10,925 students in Grades 6 to 10 participated, of which 51.4% were male and 48.6% were female, 18.3% were at risk of being overweight according to adjusted BMI, and 13.8% were overweight. The percentage of students consuming alcohol in the past 30 days was 25.1%. Illicit drug use in the past 12 months was 14.8% of the 1,907 10th graders asked, and the percentages of students who had smoked tobacco or marijuana at least once in their lifetime were 15.9% and 14.3%, respectively (see Table 1). Tobacco use and linear BMI were positively associated; those who used tobacco had higher BMI (p < .001), even after adjustment for demographics (e.g., gender, age, grade, race). After adjustment for demographics, alcohol consumption was not significantly associated with BMI. Overall, students who did not report using any illicit drug in the past 12 months had lower BMI than those who did (p < .05). The association between illicit drug use and BMI was not evident after adjustment for alcohol and tobacco use. Furthermore, we used statistical interaction to test whether the association between drug use and BMI differed in those who did and did not use tobacco and found no evidence that this was the case (p > .05). The number of drugs taken in the past 12 months was positively associated with BMI, even after adjustment for alcohol, tobacco, marijuana use (p < .05), and demographics. When each of the illicit drugs measured were tested as part of the equation, there were no significant relationships with BMI, which is possibly due to a limited sample of students who reported using each respective drug (see Table 2).
Discussion Despite the literature on BMI and substance use, there are limited data regarding the use of illicit drugs and the relationships with BMI in adolescents, thus creating a void in the literature. Though the results of the current study do not offer conclusive evidence, the data indicate a relationship between illicit drug use and BMI, which suggests the need for further investigation in this area. The number of illicit drugs used showed positive associations with BMI after adjustment for alcohol, tobacco, and demographic factors. Unadjusted associations between using illicit drugs and BMI were significant, though this effect disappeared after adjusting for tobacco and alcohol use. Because of the high correlations between smoking and drug use seen in bivariate analyses,
3
Blackstone and Herrmann Table 1. Descriptive Statistics. Variable Gender Male Female Grade 6th 7th 8th 9th 10th Race Black White Asian American Indian Pacific Islander 2+ Races Hispanic Adjusted body mass index Underweight Normal weight At risk of overweight Overweight Used tobacco Yes No Used marijuana Yes No Used alcohol Yes No Used drugs (10th grade) Yes No Illicit drugs (10th grade only) Ecstasy Amphetamines Opiates Prescription medicine Inhalants Lysergic acid diethylamide Steroids
n
Proportion
Table 2. Effects of Drug Use on Body Mass Index From Multiple Linear Regression. Overall drug use
Yes Yes Yes Yes Yes Yes Yes
5,629 5,293
51.4 48.6
2,050 2,421 2,475 2,072 1,907
18.8 22.2 22.7 18.5 17.8
2,090 5,698 455 210 105 794 2,312
17.9 48.8 3.9 1.8 0.9 6.8 19.8
394 5,839 1,680 1,276
4.3 63.6 18.3 13.8
1,679 8,731
15.9 84.1
1,488 8,881
14.3 85.7
7,770 3,343
74.9 25.1
258 1,489
14.8 85.2
57 28 11 76 43 17 8
3 1.5 0.6 4 2.3 0.9 0.4
educators may have success in targeting both illicit drug and smoking prevention simultaneously. Both may be important in obesity-prevention programs for youth as well. Though these results are not unexpected, this study is one of few specifically examining the broad range of “other drugs” and their relationship with BMI. These data are consistent with other studies, suggesting that tobacco use is associated with a risk of higher BMI trajectories in adolescents and adults (Barry & Petry, 2009; Huang et al., 2013; Pasch et al., 2008). Pasch et al. (2008)
Used drugs (yes/no) Alcohol Marijuana Tobacco Number of drugs Number of drugs taken Alcohol Tobacco Marijuana
B −.326a −.085a .288a −1.20*** B .350* −.768a −1.11a −.332a
a Reference = yes. *p < .05. ***p < .001.
posited that using tobacco in adolescence is a risk factor for developing unhealthy habits in adulthood, among which could be included those habits or behaviors affecting overweight and obesity. Results of their longitudinal study showed that it was not obese adolescents who were more prone to engage in risk behaviors (e.g., ATOD use), but that students already engaging in risk behaviors experienced greater gains in BMI. Due to the high prevalence of obesity in the United States, identifying early risk factors plays an important role in prevention initiatives. The fact that smoking was a confounding variable in the relationship between illicit drug use and BMI suggests that further research is needed to determine the interactions and temporal pathways between drug use, smoking, and BMI trajectory. Smoking, however, did not act as a confounding variable in the relationship between the number of illicit drugs used and BMI. There are limitations to this study. First, the cross-sectional design prohibits us from making any causal inferences about the time sequences regarding illicit drug use, tobacco use, and BMI. Second, we cannot determine whether relationships exist between individual illicit drugs and BMI due to limited sample size. More research with samples providing better statistical power needs to be conducted to better draw conclusions. Despite these limitations, this study, to our knowledge, is one of the first along with Denoth et al. (2011) to investigate this relationship. This study provides evidence of a positive association between the number of illicit drugs used and BMI, which suggests that illicit drugs should be further investigated in relation to BMI. Especially given the established trend between adolescent tobacco use and subsequent obesity, and the confounding effects of tobacco use in this study, it is important to determine whether using illicit drugs, smoking, or both in adolescence has a relationship with the development of health behaviors related to weight gain. By providing evidence of a relationship between illicit substances and BMI, this study offers deeper insight for
4 health educators regarding risk factors for obesity. It could be that illicit drug use is among the first of several unhealthy behaviors that adolescents, particularly smokers, engage in before adopting habits putting them at risk for obesity. If this is the case, overall healthy lifestyle choices should be emphasized in drug education in addition to avoiding drug using behavior, especially since adolescence is such a critical period of development. Past research has indicated that peer influence plays a critical role in the initiation of smoking behaviors (Kobus, 2003). Interventions based on Social Network Theory or the Theory of Planned Behavior may equip educators to address the peer and social influences that play a role in developing smoking and other drug-related behaviors. Broadly, better understanding the relationship between substance use and BMI can help educators and practitioners more quickly identify those at a high risk of adopting future unhealthy behaviors that could lead to obesity and associated chronic illness. Acknowledgments These data were obtained from the Inter-university Consortium for Political and Social Research, part of the Institute for Social Research at the University of Michigan. The Health Behavior in School Aged Children Series is sponsored by the National Institute of Child Health and Human Development.
Declaration of Conflicting Interests The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The authors received no financial support for the research, authorship, and/or publication of this article.
References Barry, D., & Petry, N. M. (2009). Associations between body mass index and substance use disorders differ by gender: Results from the national epidemiologic survey on alcohol and related conditions. Addictive Behaviors, 34, 51-60. doi:10.1016/j.addbeh.2008.08.008 Centers for Disease Control and Prevention. (2014). Body mass index. Retrieved from http://www.cdc.gov/healthyweight/ assessing/bmi/Index.html
Health Education & Behavior Denoth, F., Siciliano, V., Iozzo, P., Fortunato, L., & Molinaro, S. (2011). The association between overweight and illegal drug consumption in adolescents: Is there an underlying influence of the sociocultural environment? PLoS One, 6(11), e27358. doi:10.1371/journal.pone.0027358 Eaton, D. K., Kann, L., Kinchen, S., Shanklin, S., Flint, K. H., Hawkins, J., . . .Wechsler, H. (2012). Youth risk behavior surveillance—United States, 2011. Morbidity and Mortality Weekly Report. Surveillance Summaries (Washington, D.C.: 2002), 61(4), 1-162. Goodman, E., Hinden, B. R., & Khandelwal, S. (2000). Accuracy of teen and parental reports of obesity and body mass index. Pediatrics, 106(1 Pt 1), 52-58. Huang, D. Y. C., Lanza, H. I., Wright-Volel, K., & Anglin, M. D. (2013). Developmental trajectories of childhood obesity and risk behaviors in adolescence. Journal of Adolescence, 36, 139-148. doi:10.1016/j.adolescence.2012.10.005 Iannotti, R. J. (2013). Health Behavior in School-Aged Children (HBSC), 2009-2010: Version 1. Retrieved from https://www. icpsr.umich.edu/icpsrweb/NAHDAP/studies/34792?paging. startRow=1&q=%22mental+health%22&dataFormat%5B0% 5D=SDA&dataFormat%5B1%5D=R Johnston, L. D., O’Malley, P. M., Miech, R. A., Bachman, J. G., & Schulenberg, G. E. (2013). Monitoring the future—National results on drug use: 2013 Overview: Key findings on adolescent drug use. Retrieved from http://www.monitoringthefuture.org/pubs/monographs/mtf-overview2013.pdf Kobus, K. (2003). Peers and adolescent smoking. Addiction, 98(Suppl. 1), 37-55. Kuczmarski, R. J., Ogden, C. L., Guo, S. S., Grummer-Strawn, L. M., Flegal, K. M., Mei, Z., . . .Johnson, C. L. (2002). 2000 CDC growth charts for the United States: Methods and development. Vital Health Statistics, 11(246), 2002. Retrieved from http://www.cdc.gov/nchs/data/series/sr_11/sr11_246.pdf Liu, T. L., Yen, J. Y., Ko, C. H., Huang, M. F., Wang, P. W., Yeh, Y. C., & Yen, C. F. (2010). Associations between substance use and body mass index: Moderating effects of sociodemographic characteristics among Taiwanese adolescents. Kaohsiung Journal of Medical Sciences, 26, 281-289. doi:10.1016/S1607-551X(10)70041-3 National Institute on Drug Abuse. (2012). Drug facts: Inhalants. Retrieved from http://www.drugabuse.gov/publications/drugfacts/inhalants Pasch, K. E., Nelson, M. C., Lytle, L. A., Moe, S. G., & Perry, C. L. (2008). Adoption of risk-related factors through early adolescence: Associations with weight status and implications for causal mechanisms. Journal of Adolescent Health, 43, 387393. doi:10.1016/j.jadohealth.2008.02.009
