CLINICAL SCHOLARSHIP
Risk Factors for Current Smoking Among American and South Korean Adolescents, 2005–2011 Sung Suk Chung, PhD1 & Kyoung Hwa Joung, PhD, RN2 1 Professor, Department of Statistics and Institute of Applied Statistics, Chonbuk National University, Jeonju, Korea 2 Assistant Professor, Department of Nursing, Jeonju University, Jeonju, Korea
Key words Adolescents, risk factors, smoking, trends Correspondence Dr. Kyoung Hwa Joung, Assistant Professor, Department of Nursing, Jeonju University, Hyoja-dong 3-ga, Wansan-gu, Jeonju, Jeonbuk, 560–759 Korea. E-mail: [email protected], [email protected] Accepted: June 22, 2014 doi: 10.1111/jnu.12099
Abstract Purpose: Population data concerning smoking rates of adolescents and adults in the United States and Korea (South Korea) has highlighted the need for attention to this age group. This study compared the risk factors related to smoking and examined the gender differences with other risk factors in smoking among American and Korean adolescents between 2005 and 2011. Organizing Construct and Methods: Participants were students in grades 9–11 selected from nationally representative surveys conducted in 2005 and 2011. Findings: In 2011, similar risk factors for current smoking were identified in American and Korean adolescents. These included male gender, school grade, depression, experience of alcohol drinking, current use of alcohol, use of glue or other inhalants, and experience of sexual intercourse. Among Korean adolescents, weight perception and weight control were unique risk factors for current smoking. Interactions with gender and other risk factors in each nation were revealed. Conclusions: These risk factors, their change from earlier years, and gender differences should be recognized in the screening of vulnerable individuals for smoking and formulating effective intervention programs. Clinical Relevance: These results will provide information for the design and implementation of cessation programs for adolescents in these countries.
Adolescence, a critical period of physical and emotional development, is often a time of experimentation (Steinberg, 2008). However, even an experimental level of adolescent participation on smoking behavior may result in critical implications for future health (National Research Council and Institute of Medicine, 2005) and shortened life expectancy (Mokdad, Marks, Stroup, & Gerberding, 2004). In the absence of smoking cessation programs targeted at adolescents, persistent smoking in adolescence can increase the risk for nicotine dependence in adulthood (Caraballo, Novak, & Asman, 2009). Examination of adolescent smoking in the United States (US) and Korea has revealed markedly different prevalence of adolescent smoking among those who continue smoking as adults. 408
In the US, antismoking activism began in the mid1970s. In the intervening decades, increasing efforts have focused on reducing the prevalence of adolescent cigarette smoking in school and the community (U.S. Department of Health and Human Services, 2012). Until recently, these efforts had been very successful, with the overall rate of current smoking among U.S. adolescents declining by over 10% in the past decade (Centers for Disease Control and Prevention [CDC], 2012a, 2012b). Also, about 16.7% of U.S. adults smoke regularly, one of the lowest population smoking rates among the 34 member countries of the Organisation for Economic Co-operation and Development countries (OECD, 2011). However, more recently, the prevalence of adolescent smoking has not changed significantly (CDC, 2012b). Why smoking has not continued to decline has Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
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been questioned; whether U.S. adolescents with certain characteristics are more engaged in smoking behavior is an unanswered question. In Korea, passive policies including textual warning statements on cigarette packages became mandatory in the mid-1980s (Ministry of Health and Welfare, 2012). The cigarette industry in South Korea remains largely a government monopoly. More active cessation policies, including designation of nonsmoking areas in public places, have not been fully implemented, and prevention, intervention, and programs are still rudimentary for adolescents who commence smoking. Thus, the smoking rate among Korean adolescents has not declined appreciably (only 0.9% reduction) in the past 6 years (Korean Centers for Disease Control and Prevention [KCDC], 2012). About 40% of Korean males ࣙ 15 years of age reported regular smoking, the highest prevalence among OECD countries (Ministry of Health and Welfare, 2012). To examine temporal trends in cigarette smoking among adolescents, it is also important to clarify changes in characteristics, factors, or co-occurring behaviors. The critical reading of the eligible studies on smoking adolescents is discussed in this review (Table 1, available with online version of this article). Many studies have revealed common characteristics for smoking adolescents, although variation in smoking prevalence was considerable between and within nations. Except for a few large-scale studies (de Looze et al., 2012), most studies on adolescent smoking have been conducted in one nation, with some studies involving a geographically adjacent nation or the same racial background (Lee, Johnson, Rice, Warren & Chen, 2012; Peltzer, 2011). However, today’s generation of adolescents is markedly different in experience from prior generations, owing to the spread of global youth culture, industrialization, and other societal changes (National Research Council and Institute of Medicine, 2005). The health concerns of adolescents in one nation can be mirrored elsewhere. The changing prevalence of adolescent smoking in the US and Korea in the past decade has been amply described, and many studies have sought to ascertain the risk factors for cigarette smoking in adolescents. However, no study has examined whether these factors have changed with time. This study focused on understanding the changing trends of risk factors for smoking behaviors of American and Korean adolescents between 2005 and 2011. In addition, depending on the difference between females and males, smoking-related factors differ among countries with different cultural backgrounds (Ayers et al., 2010; French, Jang, Tait, & Anstey, 2013). Thus, we also examined other factors related to smoking for female and male adolescents within nations. Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
Aims of the Study The purposes of the study were to identify risk factors for current smoking among American and Korean adolescents, define changing trends of risk factors for current smoking in each nation between 2005 and 2011, and compare the risk factors and their trends for current smoking between American and Korean adolescents in 2011. In each nation, risk factors for smoking were compared between female and male adolescents.
Materials and Methods Participants A secondary analytical study was conducted with four national population samples: the 2005 and 2011 Korean Youth Risk Behavior Web-based Survey (KYRBWS) conducted by the KCDC (2012), and the 2005 and 2011 Youth Risk Behavior Surveillance System (YRBSS) conducted by the CDC (2012a). These data sets between the two nations were chosen because they were the first and latest complete nationwide surveys collected during the same years. These four epidemiologic surveys used a three-stage cluster sample design focused on priority health-related behaviors, including smoking, drinking, exercise, diet, and other risk behaviors. The data were analyzed with the provision of complete anonymity of participants. This study was reviewed and approved by the Research Ethics Committee of Chonbuk National University (JBNU 2013–03–005). Participants in the YRBSS surveys were students in grades 9–12. Participants in the KYRBWSs were students in grades 7–11 (2005) and 7–12 (2011). We selected grade 9 and 11 students of each data set to compare smoking behaviors and to ascertain associated risk factors among American and Korean students. Finally, the samples in this study were composed as follows: KYRBWS 2005 (n = 34,059, weighted n = 1,781,895), KYRBWS 2011 (n = 37,920, weighted n = 1,946,667), YRBSS 2005 (n = 10,332, weighted n = 10,842), and YRBSS 2011 (n = 11,600, weighted n = 11,848).
Measures The description of dependent variables (current smokers) and independent variables (characteristics or related factors) are presented in Table 2.
Data Analyses The four data sets were analyzed separately with weights of different values. Weights in the YRBSS at 2005 and 2011 were calculated to equal the total sample 409
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size and the proportion of each grade population estimates for each survey year. However, weights in the KYRBWS at 2005 and 2011 were calculated to equal the target population size consisting of all public and private school students in all regions, and the ratio of gender, school type, and school grades for each survey year. Chi-square (χ 2 ) tests were used to test the association between current smokers and nonsmokers by characteristics in each of the four groups. To compare characteristics of current smokers in the groups, only the weighted percentage of current smokers in each group is displayed. Binary logistic regression was conducted to ascertain risk factors associated with current smokers (referenced to nonsmokers) by using nine independent variables in each separate data set: gender, grade, depression, weight perception, weight control, experience of alcohol drinking, current alcohol use, glue or inhalant use, and experience of sexual intercourse. Odds ratios (ORs), good indicators for the strength of the relationships, and their confidence interval (CI) as a standard error for the log OR (Bland & Altman, 2000), were calculated. Significant interactions with gender and other risk factors were further explored by repeating the binary logistic regression analyses separately for girls and boys to compare the ORs obtained.
Results Between 2005 and 2011, the prevalence of current smoking among American adolescents was reduced from 21.7% to 15.8%, and that of Korean adolescents was reduced only marginally from 15.5% to 14.2% (Table 3, available with online version of this article). Table 4 (available with online version of this article) summarizes the results of the comparison of nonsmokers and current smokers in each group by characteristics. All variables except for gender among American adolescents at 2005 were significantly different (p < .05) between current smokers and nonsmokers in each of the four groups: grade, depression, weight perception, weight control, experience of alcohol drinking, current alcohol use, glue or inhalant use, and experience of sexual intercourse.
Risk Factors for Current Smokers Among American and Korean Adolescents in 2005 and 2011 ORs of risk factors for current smokers (referenced to nonsmokers) among American and Korean adolescents in 2005 and 2011 are summarized in Table 5 (available with online version of this article). The OR and CI of significant risk factors in each nation in 2011 are depicted in Figure 1 (available with online ver410
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sion of this article). The significant risk factors similarly identified in South Korea and the US included male gender, depression, preteen and teen experience of alcohol drinking, current use of alcohol, use of glue or inhalants, and preteen and teen experience of sexual intercourse.
Smoking Behavior of American Adolescents Based on the trends at that time by comparison of their ORs, risk factors in 2011 could be categorized as decreasing, elevated, and newly appearing (p < .001; Table 5, available with online version of this article). First, harmful but decreasing factors for current smoking among American adolescents were depression (OR change from 1.62 to 1.33), current alcohol use (OR change from 4.22 to 3.66), and glue or inhalant use (OR change from 2.43 to 2.37). Second, risky and elevating factors were alcohol experience at preteen years (OR change from 3.90 to 5.83) and teen years (OR change from 3.75 to 4.30), and experience of sexual intercourse at preteen years (OR change from 4.11 to 4.16) and teen years (OR change from 3.05 to 3.40). Third, two new risk factors for current smoking among American adolescents in 2011 relative to 2005 were male gender (OR, 1.34) and grade 11 (OR, 1.29).
Smoking Behavior of Korean Adolescents Risk factors for smoking could be further categorized as decreasing factors, increasing factors, and other factors by comparing their trends of OR values between 2005 and 2011 (p < .01; Table 5, available with online version of this article). First, consistent risky but decreasing factors were grade 10 (OR change from 1.19 to 1.03), current alcohol use (OR change from 6.28 to 4.52), and experience of sexual intercourse during preteen years (OR change from 3.72 to 2.77) and teen years (OR change from 6.92 to 5.05). Second, elevating risk factors were male gender (OR change from 1.77 to 2.82), depression (OR change from 1.36 to 1.56), weight control to gain weight (OR change from 1.16 to 1.47), and glue or inhalant use (OR change from 2.88 to 6.85). Third, two characteristics had different trends between 2005 and 2011. OR of weight perception as slightly underweight, which was a protective factor in 2005 (OR, 0.86) was a risk factor in 2011 (OR, 1.04). However, OR of weight perception as very overweight, which was a risk factor for current smoking in 2005 (OR, 1.08), was a protective factor in 2011 (OR, 0.91). OR concerning preteen experience with drinking alcohol was decreased but was still strongly associated with current smoking in 2011 (OR change from 4.41 to 3.36). Conversely, OR of teenage alcohol experience Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
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was increased in 2011 (OR change from 4.02 to 4.45).
Current Smoking for Girls and Boys in the US and Korea, 2011 Table 6 (available with online version of this article) summarizes the ORs for current smoking for girls and boys in America and Korea in 2011. Three risk factors (grade, depression, and sexual experience) increased the likelihood of smoking more for girls than boys in both the US (p < .01) and Korea (p < .001). Current alcohol use increased the likelihood of smoking for boys in the US. However, current alcohol use and glue or inhalant use increased the likelihood of smoking more for Korean girls than for boys. In the US, the influence of weight perception on smoking was more apparent for boys than for girls (p < .05), while in Korea, the influence of weight variables of weight perception and weight control on smoking were somewhat similar for both girls and boys (p < .01).
Discussion Despite geographic, demographic, and sociocontextual differences between the US and Korea, this study demonstrates the similarity and uniqueness of the risk factors for current smoking among American and Korean adolescents. It also shows trends in the risk factors for current smoking in both nations from 2005 and 2011.
Gender, School Grade, Depression, Experience of Alcohol Drinking, Current Alcohol Use, Glue or Inhalant Use, and Sexual Intercourse Initiation Male adolescents were more likely to smoke than females in the US and Korea in 2011. There are two different but important considerations in the understanding of the relationship between gender and cigarette smoking: beliefs about smoking by males and female social stigma. This is consistent with studies on adolescents in the US, Australia (French et al., 2013), Korea, Taiwan, and Thailand (Lee et al., 2012). In the male view, smoking encourages more friendships and increases personal attractiveness, success, intelligence, and masculine appeal (Lee et al., 2012). Among Koreans, this attitude on smoking behavior persists into adulthood; Korean male adults, whether they take up cigarette smoking or not, are very interested in social networking (Ayers et al., 2010). This emphasis on group relationships rather than the individual may hinder smoking cessation for Korean males. Secondly, the smoking rate in Korean adult women has been Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
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increasing over the past decade (Ministry of Health and Welfare, 2012). Korean American women smoke more at home than men, but likely underreported their smoking (Kim, Fang, Difranza, Ziedonis, & Ma, 2012). The fear of disclosure could be a barrier in seeking help for smoking cessation. Dino et al (2001) introduced a female-focused cessation program in which small groups of same-gender adolescents were guided by instructors or facilitators of the same gender. The intervention was more effective for female adolescents to quit smoking. Intervention programs considering gender could be useful for Korean smoking adolescents; its effect needs to be compared between boys and girls, and analyzed in a national comparative study. In addition, for both male and female American and Korean adolescents, cessation programs should assess their beliefs about smoking behaviors and their social linkage by using in-depth interviews. The present study comprised subjects in grades 9–11, with grade 11 identified as the highest grade-related risk for current smoking among American adolescents, and girls in grade 11 are more susceptible to smoking than boys in the same grade. On the other hand, among Korean adolescents, grade 10 (the first grade in Korean high school) was the most risky for current smoking in 2011, and girls in grade 10 are more susceptible to begin smoking than boys in the same grade. This result agrees with a previous report in the US (CDC, 2012b) that opportunities to experiment with smoking and adopting a regular smoking pattern increase with increasing school grade and adolescent age. The smoking prevalence among Korean adolescents markedly increases from lower to the next school type, such as from grade 7 (from elementary to middle school in Korea) and grade 10 (from middle to high school; KCDC, 2012). One reason may be the academic stress experienced by Korean adolescents (Hong, Kam, & Kim, 2013) in preparing for the competitive entrance exam for higher school. Stress and depression among Korean adolescents become markedly more prevalent in grade 10, mainly due to the entrance exam; troublesome experiences with use of alcohol, cigarettes, and other substances; and fighting (Ministry of Health and Welfare, 2012). In this context, the present results further define the target group of American and Korean adolescents for cessation efforts considering female gender in grade 11 in the US and grade 10 in Korea. Especially, in Korea, school nurses could plan cessation programs for adolescents who are preparing to enter high school by supplying information on stress-relieving behaviors and providing positive stress management training. Although the trends in each nation were somewhat different, depression was the consistent risk factor of current smoking in both the US and Korea, and depressed 411
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girls were more likely to smoke than depressed boys. This result is consistent with a previous study (Gallerani, Garber, & Martin, 2010) that reported an association of depression with substance use in girls more than in boys. Common adolescent expectations that perpetuate smoking include the belief that smoking will help in coping with stress and improve depressed mood (Vidrine, Anderson, Pollak, & Wetter, 2006). In addition, adolescents are experiencing hormonal changes, which make them more prone to depression relative to adults (National Center for Children in Poverty, 2009). About 36% of American girls and 38% of Korean girls reported depressive symptoms, which were higher rates than boys in the US (22%) and Korea (28%; CDC, 2012b; KCDC, 2012). Depressed girls are likely to try to smoke in the present or to become regular smokers (Leve, Harold, Van Ryzin, Elam, & Chamberlain, 2012). The relationships with smoking and mental health problems may provide an important clue for a cessation program. A study conducted on American adolescents (Minnix, Blalock, Marani, Prokhorov, & Cinciripini, 2011) found that a cessation program for adolescents that involved education in resisting peer pressure to smoke could mitigate the effect of depression on smoking behavior. Therefore, adolescents who are seeking help for smoking may well benefit from screening for their emotional and mental health, including depression. Additionally, the similar results obtained with adolescents in different countries in the present and previous studies support the use of cessation programs that include assertiveness training and emotional support. These efforts should be implemented first for girls who report depressive symptoms. Presently, in both nations, use of other substances, such as alcohol, glue, or inhalant, were consistent risk factors for smoking. American boys who drank alcohol were more likely to smoke than girls. In Korea, girls who drank alcohol and used glue or inhalants were more vulnerable to smoking than boys. Among American adolescents in 2011, preteen experience with alcohol was the most powerful risk factor for current smoking. On the other hand, glue or inhalant use among Korean adolescents was more strongly related to the risk of current smoking behavior. The association with smoking and alcohol are in general agreement with previous studies on smoking adolescents in the US (Sutfin et al., 2012) and Korea (Chung & Joung, 2013). Adolescents are in the transition stage of their cognitive decision-making capability (Steinberg, 2008) and so, relative to adults, they are more susceptible to societal pressure concerning smoking and other risky behaviors. Data collected from 2009–2011 among American preteens revealed marginally changed
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prevalence of experience with smoking, alcohol, and other substances (CDC, 2012b). Therefore, a cessation program for adolescents could more rationally address the use of alcohol as well as other substances. American boys who drank alcohol and Korean girls who use alcohol and other substances would be suitable target groups. Between 2005 and 2011, both American and Korean adolescents who had experience of sexual intercourse were more likely to smoke than the remainder of the sample. Sexual initiation, one of the most important events during adolescence, can be influenced by various factors, including friends, family, school, and other environmental factors. The present findings are consistent with previous studies in the US (Camenga, Klein, & Roy, 2006) that adolescents who engage in smoking and other substance use are more likely to become sexually active during adolescence. The cluster of early engagement in risk behaviors including alcohol, smoking, and sexual debut among adolescents could be an expression of problem behaviors, can be predictive of adolescent injury (de Looze et al., 2012), and has been strongly linked to attempted suicide (Camenga et al., 2006). Therefore, school staff or nurses need to know the connection among sexual contact, substance use, violence, and suicidal ideation, and recognize the need to establish programs to support these adolescents. Furthermore, our results expand the knowledge about more smoking-susceptible groups depending on gender: girls with sexual experiences were more susceptible to smoking than boys with sexual experiences between the US and Korea.
Weight Perception and Weight Control Weight perception was not a risk factor of current smoking among American adolescents overall, but interaction with weight perception on smoking was more apparent for boys than for girls by comparing gender. Korean adolescents in 2011 who perceived their body as not very overweight but slightly underweight and intended to gain weight were more likely to engage in cigarette smoking than adolescents in 2005, as revealed by comparison of gender interaction with weight control and weight perception with current smoking, which revealed similar findings for girls and boys. A review about weight issues and initiation of smoking among U.S. adolescents between 1980 and 2003 (Potter, Pederson, Chan, Aubut, & Koval, 2004) concluded that only 12 of 55 studies showed a relationship between perceived overweight and smoking. Moreover, in these 12 studies, gender patterns were inconsistent concerning the positive association between weight perception and smoking intention.
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Table 2. Study Variables Variables Dependent variables Current smokers and nonsmokers Independent variables Gender Grade
Depression Weight perception Weight control Experience of alcohol drinking
Current alcohol use
Glue or inhalant use Experience of sexual intercourse
Measurement
The definitions depended on participant responses concerning the number of days smoked during the last 30 days. Subjects who reported 1 day or more were considered as current smokers, while subjects who reported no experience at that time were considered as nonsmokers. Females and males were included. This item was divided into grades 9 –11 by recoding the school grade in Korea. Grade 3 of Korean middle school was considered grade 9, and grades 1 and 2 of Korean high school students were considered grades 10 and 11, respectively. This item was defined according to the response (yes or no) to a question concerning whether subjects felt so sad or hopeless almost daily for two consecutive weeks that usual activities were interrupted. This item was defined on the response to a question concerning self-description of weight (very underweight, slightly underweight, about the right weight, slightly overweight, and very overweight). This item was defined on the response to a question concerning the use of weight control to gain, lose, or maintain weight, or if weight was not a personal concern. This item was defined on the response to a question concerning when, if ever, subjects had initiated alcohol drinking (noninitiators, preteen initiators, and teen initiators). Subjects who reported no experience of alcohol drinking were considered as noninitiators. Preteen alcohol initiators (
Risk Factors for Current Smoking Among American and South Korean Adolescents, 2005–2011 Sung Suk Chung, PhD1 & Kyoung Hwa Joung, PhD, RN2 1 Professor, Department of Statistics and Institute of Applied Statistics, Chonbuk National University, Jeonju, Korea 2 Assistant Professor, Department of Nursing, Jeonju University, Jeonju, Korea
Key words Adolescents, risk factors, smoking, trends Correspondence Dr. Kyoung Hwa Joung, Assistant Professor, Department of Nursing, Jeonju University, Hyoja-dong 3-ga, Wansan-gu, Jeonju, Jeonbuk, 560–759 Korea. E-mail: [email protected], [email protected] Accepted: June 22, 2014 doi: 10.1111/jnu.12099
Abstract Purpose: Population data concerning smoking rates of adolescents and adults in the United States and Korea (South Korea) has highlighted the need for attention to this age group. This study compared the risk factors related to smoking and examined the gender differences with other risk factors in smoking among American and Korean adolescents between 2005 and 2011. Organizing Construct and Methods: Participants were students in grades 9–11 selected from nationally representative surveys conducted in 2005 and 2011. Findings: In 2011, similar risk factors for current smoking were identified in American and Korean adolescents. These included male gender, school grade, depression, experience of alcohol drinking, current use of alcohol, use of glue or other inhalants, and experience of sexual intercourse. Among Korean adolescents, weight perception and weight control were unique risk factors for current smoking. Interactions with gender and other risk factors in each nation were revealed. Conclusions: These risk factors, their change from earlier years, and gender differences should be recognized in the screening of vulnerable individuals for smoking and formulating effective intervention programs. Clinical Relevance: These results will provide information for the design and implementation of cessation programs for adolescents in these countries.
Adolescence, a critical period of physical and emotional development, is often a time of experimentation (Steinberg, 2008). However, even an experimental level of adolescent participation on smoking behavior may result in critical implications for future health (National Research Council and Institute of Medicine, 2005) and shortened life expectancy (Mokdad, Marks, Stroup, & Gerberding, 2004). In the absence of smoking cessation programs targeted at adolescents, persistent smoking in adolescence can increase the risk for nicotine dependence in adulthood (Caraballo, Novak, & Asman, 2009). Examination of adolescent smoking in the United States (US) and Korea has revealed markedly different prevalence of adolescent smoking among those who continue smoking as adults. 408
In the US, antismoking activism began in the mid1970s. In the intervening decades, increasing efforts have focused on reducing the prevalence of adolescent cigarette smoking in school and the community (U.S. Department of Health and Human Services, 2012). Until recently, these efforts had been very successful, with the overall rate of current smoking among U.S. adolescents declining by over 10% in the past decade (Centers for Disease Control and Prevention [CDC], 2012a, 2012b). Also, about 16.7% of U.S. adults smoke regularly, one of the lowest population smoking rates among the 34 member countries of the Organisation for Economic Co-operation and Development countries (OECD, 2011). However, more recently, the prevalence of adolescent smoking has not changed significantly (CDC, 2012b). Why smoking has not continued to decline has Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
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Chung & Joung
been questioned; whether U.S. adolescents with certain characteristics are more engaged in smoking behavior is an unanswered question. In Korea, passive policies including textual warning statements on cigarette packages became mandatory in the mid-1980s (Ministry of Health and Welfare, 2012). The cigarette industry in South Korea remains largely a government monopoly. More active cessation policies, including designation of nonsmoking areas in public places, have not been fully implemented, and prevention, intervention, and programs are still rudimentary for adolescents who commence smoking. Thus, the smoking rate among Korean adolescents has not declined appreciably (only 0.9% reduction) in the past 6 years (Korean Centers for Disease Control and Prevention [KCDC], 2012). About 40% of Korean males ࣙ 15 years of age reported regular smoking, the highest prevalence among OECD countries (Ministry of Health and Welfare, 2012). To examine temporal trends in cigarette smoking among adolescents, it is also important to clarify changes in characteristics, factors, or co-occurring behaviors. The critical reading of the eligible studies on smoking adolescents is discussed in this review (Table 1, available with online version of this article). Many studies have revealed common characteristics for smoking adolescents, although variation in smoking prevalence was considerable between and within nations. Except for a few large-scale studies (de Looze et al., 2012), most studies on adolescent smoking have been conducted in one nation, with some studies involving a geographically adjacent nation or the same racial background (Lee, Johnson, Rice, Warren & Chen, 2012; Peltzer, 2011). However, today’s generation of adolescents is markedly different in experience from prior generations, owing to the spread of global youth culture, industrialization, and other societal changes (National Research Council and Institute of Medicine, 2005). The health concerns of adolescents in one nation can be mirrored elsewhere. The changing prevalence of adolescent smoking in the US and Korea in the past decade has been amply described, and many studies have sought to ascertain the risk factors for cigarette smoking in adolescents. However, no study has examined whether these factors have changed with time. This study focused on understanding the changing trends of risk factors for smoking behaviors of American and Korean adolescents between 2005 and 2011. In addition, depending on the difference between females and males, smoking-related factors differ among countries with different cultural backgrounds (Ayers et al., 2010; French, Jang, Tait, & Anstey, 2013). Thus, we also examined other factors related to smoking for female and male adolescents within nations. Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
Aims of the Study The purposes of the study were to identify risk factors for current smoking among American and Korean adolescents, define changing trends of risk factors for current smoking in each nation between 2005 and 2011, and compare the risk factors and their trends for current smoking between American and Korean adolescents in 2011. In each nation, risk factors for smoking were compared between female and male adolescents.
Materials and Methods Participants A secondary analytical study was conducted with four national population samples: the 2005 and 2011 Korean Youth Risk Behavior Web-based Survey (KYRBWS) conducted by the KCDC (2012), and the 2005 and 2011 Youth Risk Behavior Surveillance System (YRBSS) conducted by the CDC (2012a). These data sets between the two nations were chosen because they were the first and latest complete nationwide surveys collected during the same years. These four epidemiologic surveys used a three-stage cluster sample design focused on priority health-related behaviors, including smoking, drinking, exercise, diet, and other risk behaviors. The data were analyzed with the provision of complete anonymity of participants. This study was reviewed and approved by the Research Ethics Committee of Chonbuk National University (JBNU 2013–03–005). Participants in the YRBSS surveys were students in grades 9–12. Participants in the KYRBWSs were students in grades 7–11 (2005) and 7–12 (2011). We selected grade 9 and 11 students of each data set to compare smoking behaviors and to ascertain associated risk factors among American and Korean students. Finally, the samples in this study were composed as follows: KYRBWS 2005 (n = 34,059, weighted n = 1,781,895), KYRBWS 2011 (n = 37,920, weighted n = 1,946,667), YRBSS 2005 (n = 10,332, weighted n = 10,842), and YRBSS 2011 (n = 11,600, weighted n = 11,848).
Measures The description of dependent variables (current smokers) and independent variables (characteristics or related factors) are presented in Table 2.
Data Analyses The four data sets were analyzed separately with weights of different values. Weights in the YRBSS at 2005 and 2011 were calculated to equal the total sample 409
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size and the proportion of each grade population estimates for each survey year. However, weights in the KYRBWS at 2005 and 2011 were calculated to equal the target population size consisting of all public and private school students in all regions, and the ratio of gender, school type, and school grades for each survey year. Chi-square (χ 2 ) tests were used to test the association between current smokers and nonsmokers by characteristics in each of the four groups. To compare characteristics of current smokers in the groups, only the weighted percentage of current smokers in each group is displayed. Binary logistic regression was conducted to ascertain risk factors associated with current smokers (referenced to nonsmokers) by using nine independent variables in each separate data set: gender, grade, depression, weight perception, weight control, experience of alcohol drinking, current alcohol use, glue or inhalant use, and experience of sexual intercourse. Odds ratios (ORs), good indicators for the strength of the relationships, and their confidence interval (CI) as a standard error for the log OR (Bland & Altman, 2000), were calculated. Significant interactions with gender and other risk factors were further explored by repeating the binary logistic regression analyses separately for girls and boys to compare the ORs obtained.
Results Between 2005 and 2011, the prevalence of current smoking among American adolescents was reduced from 21.7% to 15.8%, and that of Korean adolescents was reduced only marginally from 15.5% to 14.2% (Table 3, available with online version of this article). Table 4 (available with online version of this article) summarizes the results of the comparison of nonsmokers and current smokers in each group by characteristics. All variables except for gender among American adolescents at 2005 were significantly different (p < .05) between current smokers and nonsmokers in each of the four groups: grade, depression, weight perception, weight control, experience of alcohol drinking, current alcohol use, glue or inhalant use, and experience of sexual intercourse.
Risk Factors for Current Smokers Among American and Korean Adolescents in 2005 and 2011 ORs of risk factors for current smokers (referenced to nonsmokers) among American and Korean adolescents in 2005 and 2011 are summarized in Table 5 (available with online version of this article). The OR and CI of significant risk factors in each nation in 2011 are depicted in Figure 1 (available with online ver410
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sion of this article). The significant risk factors similarly identified in South Korea and the US included male gender, depression, preteen and teen experience of alcohol drinking, current use of alcohol, use of glue or inhalants, and preteen and teen experience of sexual intercourse.
Smoking Behavior of American Adolescents Based on the trends at that time by comparison of their ORs, risk factors in 2011 could be categorized as decreasing, elevated, and newly appearing (p < .001; Table 5, available with online version of this article). First, harmful but decreasing factors for current smoking among American adolescents were depression (OR change from 1.62 to 1.33), current alcohol use (OR change from 4.22 to 3.66), and glue or inhalant use (OR change from 2.43 to 2.37). Second, risky and elevating factors were alcohol experience at preteen years (OR change from 3.90 to 5.83) and teen years (OR change from 3.75 to 4.30), and experience of sexual intercourse at preteen years (OR change from 4.11 to 4.16) and teen years (OR change from 3.05 to 3.40). Third, two new risk factors for current smoking among American adolescents in 2011 relative to 2005 were male gender (OR, 1.34) and grade 11 (OR, 1.29).
Smoking Behavior of Korean Adolescents Risk factors for smoking could be further categorized as decreasing factors, increasing factors, and other factors by comparing their trends of OR values between 2005 and 2011 (p < .01; Table 5, available with online version of this article). First, consistent risky but decreasing factors were grade 10 (OR change from 1.19 to 1.03), current alcohol use (OR change from 6.28 to 4.52), and experience of sexual intercourse during preteen years (OR change from 3.72 to 2.77) and teen years (OR change from 6.92 to 5.05). Second, elevating risk factors were male gender (OR change from 1.77 to 2.82), depression (OR change from 1.36 to 1.56), weight control to gain weight (OR change from 1.16 to 1.47), and glue or inhalant use (OR change from 2.88 to 6.85). Third, two characteristics had different trends between 2005 and 2011. OR of weight perception as slightly underweight, which was a protective factor in 2005 (OR, 0.86) was a risk factor in 2011 (OR, 1.04). However, OR of weight perception as very overweight, which was a risk factor for current smoking in 2005 (OR, 1.08), was a protective factor in 2011 (OR, 0.91). OR concerning preteen experience with drinking alcohol was decreased but was still strongly associated with current smoking in 2011 (OR change from 4.41 to 3.36). Conversely, OR of teenage alcohol experience Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
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was increased in 2011 (OR change from 4.02 to 4.45).
Current Smoking for Girls and Boys in the US and Korea, 2011 Table 6 (available with online version of this article) summarizes the ORs for current smoking for girls and boys in America and Korea in 2011. Three risk factors (grade, depression, and sexual experience) increased the likelihood of smoking more for girls than boys in both the US (p < .01) and Korea (p < .001). Current alcohol use increased the likelihood of smoking for boys in the US. However, current alcohol use and glue or inhalant use increased the likelihood of smoking more for Korean girls than for boys. In the US, the influence of weight perception on smoking was more apparent for boys than for girls (p < .05), while in Korea, the influence of weight variables of weight perception and weight control on smoking were somewhat similar for both girls and boys (p < .01).
Discussion Despite geographic, demographic, and sociocontextual differences between the US and Korea, this study demonstrates the similarity and uniqueness of the risk factors for current smoking among American and Korean adolescents. It also shows trends in the risk factors for current smoking in both nations from 2005 and 2011.
Gender, School Grade, Depression, Experience of Alcohol Drinking, Current Alcohol Use, Glue or Inhalant Use, and Sexual Intercourse Initiation Male adolescents were more likely to smoke than females in the US and Korea in 2011. There are two different but important considerations in the understanding of the relationship between gender and cigarette smoking: beliefs about smoking by males and female social stigma. This is consistent with studies on adolescents in the US, Australia (French et al., 2013), Korea, Taiwan, and Thailand (Lee et al., 2012). In the male view, smoking encourages more friendships and increases personal attractiveness, success, intelligence, and masculine appeal (Lee et al., 2012). Among Koreans, this attitude on smoking behavior persists into adulthood; Korean male adults, whether they take up cigarette smoking or not, are very interested in social networking (Ayers et al., 2010). This emphasis on group relationships rather than the individual may hinder smoking cessation for Korean males. Secondly, the smoking rate in Korean adult women has been Journal of Nursing Scholarship, 2014; 46:6, 408–415. C 2014 Sigma Theta Tau International
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increasing over the past decade (Ministry of Health and Welfare, 2012). Korean American women smoke more at home than men, but likely underreported their smoking (Kim, Fang, Difranza, Ziedonis, & Ma, 2012). The fear of disclosure could be a barrier in seeking help for smoking cessation. Dino et al (2001) introduced a female-focused cessation program in which small groups of same-gender adolescents were guided by instructors or facilitators of the same gender. The intervention was more effective for female adolescents to quit smoking. Intervention programs considering gender could be useful for Korean smoking adolescents; its effect needs to be compared between boys and girls, and analyzed in a national comparative study. In addition, for both male and female American and Korean adolescents, cessation programs should assess their beliefs about smoking behaviors and their social linkage by using in-depth interviews. The present study comprised subjects in grades 9–11, with grade 11 identified as the highest grade-related risk for current smoking among American adolescents, and girls in grade 11 are more susceptible to smoking than boys in the same grade. On the other hand, among Korean adolescents, grade 10 (the first grade in Korean high school) was the most risky for current smoking in 2011, and girls in grade 10 are more susceptible to begin smoking than boys in the same grade. This result agrees with a previous report in the US (CDC, 2012b) that opportunities to experiment with smoking and adopting a regular smoking pattern increase with increasing school grade and adolescent age. The smoking prevalence among Korean adolescents markedly increases from lower to the next school type, such as from grade 7 (from elementary to middle school in Korea) and grade 10 (from middle to high school; KCDC, 2012). One reason may be the academic stress experienced by Korean adolescents (Hong, Kam, & Kim, 2013) in preparing for the competitive entrance exam for higher school. Stress and depression among Korean adolescents become markedly more prevalent in grade 10, mainly due to the entrance exam; troublesome experiences with use of alcohol, cigarettes, and other substances; and fighting (Ministry of Health and Welfare, 2012). In this context, the present results further define the target group of American and Korean adolescents for cessation efforts considering female gender in grade 11 in the US and grade 10 in Korea. Especially, in Korea, school nurses could plan cessation programs for adolescents who are preparing to enter high school by supplying information on stress-relieving behaviors and providing positive stress management training. Although the trends in each nation were somewhat different, depression was the consistent risk factor of current smoking in both the US and Korea, and depressed 411
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girls were more likely to smoke than depressed boys. This result is consistent with a previous study (Gallerani, Garber, & Martin, 2010) that reported an association of depression with substance use in girls more than in boys. Common adolescent expectations that perpetuate smoking include the belief that smoking will help in coping with stress and improve depressed mood (Vidrine, Anderson, Pollak, & Wetter, 2006). In addition, adolescents are experiencing hormonal changes, which make them more prone to depression relative to adults (National Center for Children in Poverty, 2009). About 36% of American girls and 38% of Korean girls reported depressive symptoms, which were higher rates than boys in the US (22%) and Korea (28%; CDC, 2012b; KCDC, 2012). Depressed girls are likely to try to smoke in the present or to become regular smokers (Leve, Harold, Van Ryzin, Elam, & Chamberlain, 2012). The relationships with smoking and mental health problems may provide an important clue for a cessation program. A study conducted on American adolescents (Minnix, Blalock, Marani, Prokhorov, & Cinciripini, 2011) found that a cessation program for adolescents that involved education in resisting peer pressure to smoke could mitigate the effect of depression on smoking behavior. Therefore, adolescents who are seeking help for smoking may well benefit from screening for their emotional and mental health, including depression. Additionally, the similar results obtained with adolescents in different countries in the present and previous studies support the use of cessation programs that include assertiveness training and emotional support. These efforts should be implemented first for girls who report depressive symptoms. Presently, in both nations, use of other substances, such as alcohol, glue, or inhalant, were consistent risk factors for smoking. American boys who drank alcohol were more likely to smoke than girls. In Korea, girls who drank alcohol and used glue or inhalants were more vulnerable to smoking than boys. Among American adolescents in 2011, preteen experience with alcohol was the most powerful risk factor for current smoking. On the other hand, glue or inhalant use among Korean adolescents was more strongly related to the risk of current smoking behavior. The association with smoking and alcohol are in general agreement with previous studies on smoking adolescents in the US (Sutfin et al., 2012) and Korea (Chung & Joung, 2013). Adolescents are in the transition stage of their cognitive decision-making capability (Steinberg, 2008) and so, relative to adults, they are more susceptible to societal pressure concerning smoking and other risky behaviors. Data collected from 2009–2011 among American preteens revealed marginally changed
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prevalence of experience with smoking, alcohol, and other substances (CDC, 2012b). Therefore, a cessation program for adolescents could more rationally address the use of alcohol as well as other substances. American boys who drank alcohol and Korean girls who use alcohol and other substances would be suitable target groups. Between 2005 and 2011, both American and Korean adolescents who had experience of sexual intercourse were more likely to smoke than the remainder of the sample. Sexual initiation, one of the most important events during adolescence, can be influenced by various factors, including friends, family, school, and other environmental factors. The present findings are consistent with previous studies in the US (Camenga, Klein, & Roy, 2006) that adolescents who engage in smoking and other substance use are more likely to become sexually active during adolescence. The cluster of early engagement in risk behaviors including alcohol, smoking, and sexual debut among adolescents could be an expression of problem behaviors, can be predictive of adolescent injury (de Looze et al., 2012), and has been strongly linked to attempted suicide (Camenga et al., 2006). Therefore, school staff or nurses need to know the connection among sexual contact, substance use, violence, and suicidal ideation, and recognize the need to establish programs to support these adolescents. Furthermore, our results expand the knowledge about more smoking-susceptible groups depending on gender: girls with sexual experiences were more susceptible to smoking than boys with sexual experiences between the US and Korea.
Weight Perception and Weight Control Weight perception was not a risk factor of current smoking among American adolescents overall, but interaction with weight perception on smoking was more apparent for boys than for girls by comparing gender. Korean adolescents in 2011 who perceived their body as not very overweight but slightly underweight and intended to gain weight were more likely to engage in cigarette smoking than adolescents in 2005, as revealed by comparison of gender interaction with weight control and weight perception with current smoking, which revealed similar findings for girls and boys. A review about weight issues and initiation of smoking among U.S. adolescents between 1980 and 2003 (Potter, Pederson, Chan, Aubut, & Koval, 2004) concluded that only 12 of 55 studies showed a relationship between perceived overweight and smoking. Moreover, in these 12 studies, gender patterns were inconsistent concerning the positive association between weight perception and smoking intention.
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Table 2. Study Variables Variables Dependent variables Current smokers and nonsmokers Independent variables Gender Grade
Depression Weight perception Weight control Experience of alcohol drinking
Current alcohol use
Glue or inhalant use Experience of sexual intercourse
Measurement
The definitions depended on participant responses concerning the number of days smoked during the last 30 days. Subjects who reported 1 day or more were considered as current smokers, while subjects who reported no experience at that time were considered as nonsmokers. Females and males were included. This item was divided into grades 9 –11 by recoding the school grade in Korea. Grade 3 of Korean middle school was considered grade 9, and grades 1 and 2 of Korean high school students were considered grades 10 and 11, respectively. This item was defined according to the response (yes or no) to a question concerning whether subjects felt so sad or hopeless almost daily for two consecutive weeks that usual activities were interrupted. This item was defined on the response to a question concerning self-description of weight (very underweight, slightly underweight, about the right weight, slightly overweight, and very overweight). This item was defined on the response to a question concerning the use of weight control to gain, lose, or maintain weight, or if weight was not a personal concern. This item was defined on the response to a question concerning when, if ever, subjects had initiated alcohol drinking (noninitiators, preteen initiators, and teen initiators). Subjects who reported no experience of alcohol drinking were considered as noninitiators. Preteen alcohol initiators (
