Addictive Behaviors 39 (2014) 189–195
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Addictive Behaviors
Effectiveness of school-based smoking intervention in middle school students of Linzhi Tibetan and Guangzhou Han ethnicity in China Long Chen a,1, Yan Chen a,b,1, Yuantao Hao a,⁎, Jing Gu a,⁎⁎, Yan Guo a,c, Wenhua Ling d a
Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China Guangdong Institute of Public Health, Center for Disease Control and Prevention of Guangdong Province, Guangzhou 510080, China Sun Yat-sen Center for Migrant Health Policy, Guangzhou 510080, China d Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China b c
H I G H L I G H T S • • • • •
Smoking situation of Linzhi Tibetan is more serious than that of Guangzhou Han. The intervention was effective in increase of knowledge in both two ethnic groups. The intervention did not change smoking behavior in either ethnic group. The intervention changed attitude toward smoking in Tibetan but not so in Han. This intervention was more effective for Tibetan when compared with Han ethnic group.
a r t i c l e
i n f o
Keywords: School-based smoking intervention Middle school students Tibetan Han China
a b s t r a c t Purpose: The purpose of this paper is to assess the effectiveness of school-based intervention aimed to increase knowledge, to change attitudes and to reduce smoking-related behavior in both Linzhi Tibetan and Guangzhou Han middle school students in China. Design: A concurrent intervention study was conducted in both Linzhi and Guangzhou. Two schools were randomly chosen and one was randomly assigned to the intervention group and the other to the control group in both settings. Setting/participants: Participants were grade one and grade two middle school students drawn from two schools in Linzhi, Tibet Autonomous Region (southwest China) and two schools in Guangzhou, Guangdong Province (south China). Intervention: The intervention program lasted for one year and covered three aspects: health policies in school, health environment in school and personal health skills. Main outcome measures: Primary outcomes were smoking-related knowledge, attitudes and behavior (including ever smoking, daily smoking, weekly smoking and current smoking) and were measured by a self-administered questionnaire before and after the intervention. Results: This intervention increased smoking-related knowledge in both Tibetan (β = 1.32, 95% CI (0.87–1.77)) and Han ethnic groups (β = 0.47, 95% CI (0.11–0.83)). It changed attitudes toward smoking in Tibetan (β = 1.47, 95% CI (0.06–2.87)) but not so in Han (β = −0.33, 95% CI (−1.68–1.01)). The intervention changed the prevalence of smoking in neither ethnic groups (P N 0.05). Conclusions: The impact of school-based smoking intervention is different among Tibetan and Han students. This intervention was more effective for Tibetans when compared with the Han ethnic group. More research is needed on how intervention can be adapted to address ethnic and cultural differences. © 2013 Elsevier Ltd. All rights reserved.
1. Introduction ⁎ Correspondence to: H. Yuantao, School of Public Health, Sun Yat-sen University, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China. Tel./fax: +86 20 87331587. ⁎⁎ Correspondence to: G. Jing, School of Public Health, Sun Yat-sen University, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China.Tel.: + 86 20 87331470; fax: + 86 20 87330446. E-mail addresses: [email protected] (Y. Hao), [email protected] (J. Gu). 1 Co-first author. 0306-4603/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.addbeh.2013.09.026
1.1. Smoking is a grave concern globally Health problems caused by tobacco usage are still severe (WHO, 2008, 2009c). The World Health Organization (WHO) estimates that there are about one billion smokers worldwide (WHO, 2010). Almost 6million people die from tobacco use or exposure each year, accounting
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for 6% of all female deaths and 12% of all male deaths in the world (WHO, 2009a).
1.2. Adolescent smoking status is severe Adult smoking habits are mostly formed in adolescence (Warren, Jones, Eriksen, & Asma, 2006). Monitoring the Future study in 2012 shows that 19% of 12th graders were current smokers in the U.S. (Johnston, Malley, Bachman, & Schulenberg, 2012). The European School Survey Project on Alcohol and Other Drugs (ESPAD) in 2011 shows that on average, 28% of the students in the ESPAD countries had used cigarettes during the past 30 days (Hibell et al., 2011). The Global Youth Tobacco Survey (GYTS) from Indonesia showed that 41.0% of the boys and 3.5% of the girls currently smoked cigarettes (WHO, 2009b).
1.3. Smoking status in China China is the world's largest tobacco producer, consumer and one of 14 countries of high burden of tobacco use (Hsia et al., 2010). Previous research of adolescents reported that 28% to 43% of males and 1% to 11% of females identified themselves as smokers (Chen et al., 2006). Additional data suggest that smoking rates in adolescents have been on the rise, and the age of smoking initiation is becoming younger (Zhang, Tian, Hou, & Li, 2003). Reducing the prevalence of tobacco use among adolescents remains a key public health priority in China (Hastings & Angus, 2008).
1.4. Difference exists among ethnic groups People of different ethnic groups usually have different dialects and culture, resulting in disparities in behaviors among ethnic groups (Caraballo, Yee, Gfroerer, & Mirza, 2008). Thus, the effects of the smoking intervention program may be distinct between ethnic groups. For example, one study reported that the non-Arab American students were 23% less likely to smoke cigarettes as compared to Arab American youths (Rice, Weglicki, Templin, Jamil, & Hammad, 2010). In another study, Hispanics were more likely than whites to quit smoking (Kahende, Malarcher, Teplinskaya, & Asman, 2011). China is a multi-ethnic country covering a vast territory. The Han nationality is the majority group with a population of over 1.2 billion, which accounts for 91.5% of the Chinese population. Tibetans have a population of over 5.41million, which ranks eighth among all minorities (National Bureau of Statistics of China, 2010). Few studies have examined Tibetan adolescents' smoking rate. However, one study in Linzhi, Tibet showed that 14.8% of middle school students were current cigarette smokers (Chen et al., 2010), indicating a need for greater clarity about smoking rates. Furthermore, there are no reported intervention studies targeting Tibetan adolescents' smoking status.
1.6. Purposes and hypothesis of this study The purposes of the current study are to examine the smoking status of middle school students at two sites (Linzhi and Guangzhou) between two ethnic groups (Tibetan and Han), and to compare the effectiveness of the intervention among students of these two ethnics groups. We hypothesize that the intervention is effective in controlling and preventing smoking in both locations and that the size of the effect vary depending on distinct ethnic characteristics.
2. Methods 2.1. Settings The study was conducted in Linzhi of Tibet Autonomous Region (southwest China) and Guangzhou of Guangdong Province (south China). Linzhi is located in the southeast of Tibet Autonomous Region with a total population of 140,000, of which more than 90% are Tibetans. Guangzhou is the capital city of Guangdong Province with a population of 12.7 million, the majority of which is Han.
2.2. Study design A school-based intervention study was conducted from September 2008 to September 2009 in both Linzhi and Guangzhou, with intervention group and control group at each site. School-based tobacco control intervention was given to the intervention group while no specific intervention was given to the control group. Differences in attitudes, knowledge and behaviors between the intervention and control groups were compared each site separately before and after the intervention. In addition, the intervention effects between the two study sites were compared.
2.3. Participants Participants of the study were first and second year middle school students. Randomization occurred at the school level to avoid contamination between groups. Two out of seven middle schools were randomly selected in Linzhi and two were randomly selected in Guangzhou. The two chosen schools of each site were then randomly assigned to the intervention or control group. All students of first and second years of the selected schools (712 in Linzhi and 1,105 in Guangzhou) were invited and all of them agreed to participate in the study. Written informed consent was obtained from school teachers and verbal informed consent was obtained from the students. Approval for the design and data collection procedures was obtained beforehand from the ethic committee of the School of Public Health, Sun Yat-sen University.
2.4. Data collection 1.5. Background on school-based smoking intervention School-based smoking intervention programs are considered to be one of the most effective strategies for reducing smoking prevalence among adolescents (Gingiss, Roberts-Gray, & Boerm, 2006). Such programs aim at providing smoking-related health information, and pursue strategies based on social competence or social influence (Wiehe, Garrison, Christakis, Ebel, & Rivara, 2005). School-based smoking intervention programs have shown evidence to improve adolescents' smoking knowledge, attitudes (Lee, Wu, Lai, & Chu, 2007; Park, 2006) and decrease smoking behaviors both in China and globally (Chen, Fang, Li, Stanton, & Lin, 2006; Sun, Miyano, Rohrbach, Dent, & Sussman, 2007).
Questionnaire surveys were conducted on all study objects before and after the intervention (i.e., the baseline survey in September 2008 and the follow-up survey in September 2009). Research assistants were recruited from the school of public health at the medical colleges at each site and received trainings on how to collect data and perform quality control. Surveys were completed in classrooms under supervision of qualified research assistants. Pre-post surveys were anonymous, and matched on sex, school, ethnicity, first letters of family name and first name. Pre-post surveys which could not be matched were excluded. A total of 709 and 1098 matched questionnaires were collected in Linzhi (correspondence rate 99.6%) and Guangzhou (correspondence rate 99.4%) respectively.
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2.5. Intervention The contents of intervention were designed according to the literature of successful interventions in adolescents' tobacco control (Lawrence & Marshall, 1991; Wen, Chen, & Liang, 2007; Wen et al., 2007; WHO, 1995). In this study, the intervention targeted at students and teachers in the school. The preliminary list of intervention activities was generated by a panel of health education experts, after a critical review of Chinese and English literature. Then this list was revised after in-depth interviews with school administrators to ensure feasibility. Focus group discussions with smoking students were also held to discuss the acceptability of interventions. Families were not involved because most of the Tibetan students live in school. The intervention program lasted for an entire school year and covered following aspects: (1) Health Policies in School. In the two intervention schools, a tobacco control committees headed by the principal was established respectively; regulations on smoking were made at the beginning of the study (“e.g., No smoking was allowed in school”). (2) Health Environment in school. 30 no-smoking signs were placed in the school yards. Peer education was conducted to help smokers to quit smoking. Peer educators were the most popular students elected by classmates and received special trainings on smoking prevention-related knowledge and communication skills. At least once during the study period, peer educators shared smoking-related knowledge with each smoker in his/her class, encouraged them to quit, and not to give or accept cigarettes during social activities. The peer educators were also core members of the Tobacco Control Group. Under the help of teachers, they organized group activities quarterly to discuss harms of smoking to one's health, to share knowledge of smoking prevention with students in each class. There were 20 groups in Linzhi and 26 groups in Guangzhou. Teachers were required not to smoke in front of students. (3) Personal Health Skills. Brochures of health hazards of smoking were issued to all participants twice (October 2008 and March 2009). Blackboard newsletter (chalk board at the back of the classroom for information sharing), class theme meetings of smoking control, posters and publicity pictures were made and renewed quarterly. Smoking-related health education lectures were given twice (November 2008 and April 2009). Students participated in smokingcessation related activities including essay competitions, signing for non-smoking pledge, No-Tobacco-Day theme activities, selfproducing newspaper competition and logo design contests.
2.6. Measurements Background characteristics of all students (sex, age, nationality, school and grade) were collected. Students' smoking-related knowledge, attitudes and behaviors were measured by scales which were revised from Guangzhou City Middle School Students Smoking Status Questionnaire developed by Chen and his colleagues (Wen, Chen, & Lu, 2005, 2006). Questions regarding smoking in school included smoking status of peers and teachers, whether students' smoking was permitted by teachers and parents, tobacco control advocacy and tobacco control activities in the schools, and passive smoking at schools. Smoking-related knowledge was measured by 20 items (e.g., “whether passive smoking is harmful to the body?”). Knowledge score was calculated by summing up correct individual item responses. Smoking-related attitudes consisted of 18 items (e.g., “Not accept others' cigarette is impolite”). The answers ranged from “strongly disagree” (=1) to “strongly agree” (=5). The attitudes score was a sum of 18 items, with a higher score indicating more negative attitudes towards smoking. Evaluation of psychometric features was acceptable (Cronbach's alpha = 0.86, RMSEA = 0.05, CFI = 0.98).
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Smoking behaviors included whether a person smoked, smoked daily, smoked weekly, or is smoking currently (WHO, 1982; Zheng, 1992). Ever smoking was defined as having ever used cigarettes, even one or two times. Weekly smoking was defined as smoking at least one cigarette per week, which continued or was cumulating for three months or more, but cannot meet the daily smoker's standard. Daily smoking was defined as smoking at least one cigarette per day, which continued or was cumulating for three months or more. Current smoking was defined as smoking one or more cigarettes in the past 30 days.
2.7. Statistical analysis Descriptive analysis and univariate analysis were conducted to test whether the background characteristics (age, sex, and grade) were balanced between the intervention and control groups. Possible confounders were adjusted in the subsequent multivariate analyses. The association between follow-up smoking status (dependent variable, yes vs. no) and intervention (independent variable, yes vs. no) was analyzed by using unconditional logistic regression models. Similarly, the associations between follow-up knowledge/attitude (dependent variable) and intervention (independent variable) were analyzed by using linear regression models. To compare the differences in the effects of the intervention between Linzhi Tibetan and Guangzhou Han, the significance of moderating (interaction) effects of region on the association between intervention and outcomes were tested by using multivariate regression models, each including region, intervention, region*intervention and adjusting for baseline confounders. Effect size (Cohen's d) was defined as the difference in the change of prevalence or mean scores between the intervention and control groups divided by the pooled standard deviation (Cohen, 1988). SPSS (version 17.0) was used for all the statistical analyses. Statistical significance was determined at the P b 0.05 level.
3. Result 3.1. Baseline status of all participants Of all the students, the average age was 14.5 ± 1.1 years old, with 50.4% being boys. The intervention group in Linzhi (14.8 ± 1.4 years old) was slightly younger than the control group (15.1 ± 1.2 years old), while in Guangzhou, there were differences in sex and age between the intervention and control groups. The intervention and control groups in Linzhi were comparable in smoking behaviors but not in knowledge and attitudes. In Guangzhou, the intervention and control groups were comparable in smoking behaviors and knowledge but not in attitudes (Table 1). Tibetan students had lower scores in smoking-related knowledge (5.0 ± 3.0 vs. 7.3 ± 3.0, P b 0.001) and attitudes (67.2 ± 9.6 vs. 76.8 ± 10.1, P b 0.001) but higher rates of smoking behavior (ever smoking 33.1%, weekly smoking 1.8%, daily smoking 8.5%, and current smoking 11.4%) than Han students (7.5%, 0.3%, 0.5% and 1.1%, respectively, P b 0.05). Significance differences existed between the two ethnic groups in age and sex.
3.2. Self-reported differences in smoking-related environment between Linzhi Tibetans and Guangzhou Han at baseline As shown in Table 2, compared to their counterparts in Guangzhou, in Linzhi, a higher proportion of peers and teachers smoked in school; a higher proportion of students perceived there was someone smoking in school and were allowed to smoke by their parents or teachers; and a lower proportion reported there were health-related advocacy posters or blackboard newsletters in school.
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Table 1 Baseline Comparisons of students of the four schools in Linzhi and Guangzhou. Linzhi Tibetan Total
Sex⁎ Male Female Agea⁎ Grade One Two Smoking-related knowledgea⁎ Smoking-related attitudes a⁎ Smoking-related behavior Ever smoking ⁎ Weekly smoking⁎ Daily smoking ⁎ Current smoking ⁎
Guangzhou Han Intervention
Control
(n = 709)
(n = 349)
(n = 360)
n (%)
n (%)
n (%)
P
306 403 15.0
(43.2) (56.8) (1.3)
155 194 14.8
(44.4) (55.6) (1.4)
151 209 15.1
(41.9) (58.1) (1.2)
0.507
394 315 5.0 67.2
(55.6) (44.4) (3.0) (9.6)
200 149 4.4 65.7
(57.3) (42.7) (2.6) (9.5)
194 166 5.5 68.8
(53.9) (46.1) (3.3) (9.4)
0.360
235 13 60 81
(33.1) (1.8) (8.5) (11.4)
123 4 35 41
(35.2) (1.1) (10.0) (11.7)
112 9 25 40
(31.1) (2.5) (6.9) (11.1)
Total
Intervention
Control
(n = 1,098)
(n = 592)
(n = 506)
n (%)
n (%)
n (%)
P
604 494 14.2
(55.0) (45.0) (0.8)
308 284 14.3
(52.0) (48.0) (0.9)
296 210 14.2
(58.5) (41.5) (0.8)
b0.001 b0.001
582 516 7.3 76.8
(53.0) (47.0) (3.0) (10.1)
300 292 7.4 75.9
(50.7) (49.3) (3.0) (9.9)
282 224 7.2 77.9
(55.7) (44.3) (2.9) (10.2)
0.296 b0.001
0.243 0.179 0.140 0.790
82 3 5 12
(7.5) (0.3) (0.5) (1.1)
52 2 2 8
(8.8) (0.3) (0.3) (1.4)
30 1 3 4
(5.9) (0.2) (0.6) (0.8)
0.073 1.000 0.666 0.373
0.020
0.032 0.002 0.094
a : Mean and standard deviation. *: There is statistically significant differences between Linzhi District Tibetan and Guangzhou Han (combining the intervention and control groups) (P b 0.05).
3.3. Effectiveness of intervention on smoking-related knowledge and attitudes score In Linzhi, after adjusting for baseline confounders, students of the intervention group had higher scores of smoking-related knowledge (βa = 1.32, 95%CI = 0.87–1.77, P b 0.001) and smoking-related attitudes (βa = 1.47, 95%CI 0.06–2.87, P = 0.041) than those of the control group after intervention. In Guangzhou, using similar methods, the intervention group had higher scores of smoking-related knowledge (βa = 0.47, 95%CI 0.11–0.83, P = 0.010) but similar scores of smokingrelated attitudes (βa = −0.33, 95%CI = 1.68–1.01, P = 0.625) as compared to the control group. The effect size of the intervention on knowledge scores in Linzhi was 0.54 while it was 0.08 in Guangzhou (data not tabulated).
3.4. Effectiveness of intervention on smoking behavior In Linzhi, the pre-post test showed that the increment of current smoking rate (but not the other three smoking behaviors) in control group was significant (from 11.1% to 18.1% P b 0.01). None of the smoking rates changed significantly in the intervention group. In Guangzhou, the differences of changes of all four smoking-related behaviors in both intervention and control groups were not significant. In Linzhi, after the intervention, none of the four smoking behaviors indicators was significantly different between the intervention and control groups after adjusting for baseline confounders. Similar findings were revealed for those in Guangzhou (Table 3).
3.5. Moderating effects of region on intervention The moderating effect of region was significant for the association between intervention and smoking-related knowledge: βa of the interaction term (region*intervention) was −0.22 (95%CI = −1.39 to −0.24, P = 0.005). Similar finding was found for smoking-related attitudes (βa of the interaction term was −0.16, 95% CI = −4.04 to −0.04, P = 0.045). The moderating effects of region were non-significant for the association between intervention and all studied smoking-related behaviors (adjusted odds ratios ranged from 1.42 to 5.06, P N 0.05) (data not tabulated). 3.6. Participation of the intervention of the two intervention groups Of all intervention activities, the participation rates ranged from 20.4% (essay competition) to 68.7% (blackboard newsletter) in Linzhi. In Guangzhou, the participation rates were from 15.5% (Tobacco Control Group) to 53.3% (saw or heard of regulations on smoking). The Linzhi Tibetan had higher participation rates than Guangzhou Han in many intervention activities (Table 4). 4. Discussion In this school-based pilot study, the effectiveness of the one-year intervention was assessed on aspects of smoking-related behaviors, knowledge and attitudes. The results showed that the smoking situation of middle school students of Linzhi, Tibet was more serious than that of their counterparts of Guangzhou Han. The intervention increased the
Table 2 Differences in smoking-related environment in school between Linzhi Tibetans and Guangzhou Han at baseline.
Peers/teachers smoke in school Peers Head teachers Other teachers Peers or teachers Passive smoking in school Smoking in school is permitted by teachers One's smoking in school is permitted by parents Tobacco control-related advocacy posters Tobacco control-related activities organized by school
Linzhi Tibetans (%)
Guangzhou Han (%)
χ2
P
54.0 20.7 68.9 88.4 44.7 6.1 8.3 32.7 28.4
28.7 6.6 49.6 74.8 32.8 2.8 2.5 37.8 29.8
184.3 125.4 103.6 81.6 40.9 19.3 50.8 7.5 0.7
b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 0.006 0.405
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Table 3 Effects of interventions on students' smoking behaviors and scores of attitudes and knowledge. Linzhi Tibetan (%)
Ever smoking Weekly smoking Daily smoking Current smoking Knowledge score Attitudes score
Intervention group (%)
Control group (%)
33.2 2.3 7.5 16.3 9.1 ± 3.1a 70.0 ± 9.7a
33.6 4.2 11.1 18.1 7.9 ± 2.8 a 68.1 ± 8.0a
Guangzhou Han (%) Univariate
Adjusted
ORu/βu
95%CI
ORa/βa
95%CI
1.02 1.85 1.55 1.13 1.19 ** 1.86*
(0.74–1.39) (0.78–4.43) (0.93–2.61) (0.76–1.67) (0.75–1.63) (0.50–3.22)
0.97 1.63 1.43 1.03 1.32** 1.47*
(0.71–1.33) (0.67–3.95) (0.82–2.47) (0.69–1.53) (0.87–1.77) (0.06–2.87)
Intervention group (%)
Control group (%)
9.6 0.3 1.4 2.4 11.6 ± 2.8a 77.6 ± 10.5a
9.1 0.2 1.4 1.8 11.1 ± 3.2a 77.7 ± 11.6a
Univariate
Adjusted
ORu/βu
95%CI
ORa/βa
95%CI
0.94 0.58 1.02 0.75 0.51 * −0.05
(0.62–1.41) (0.05–6.46) (0.37–2.84) (0.32–1.74) (0.15–0.87) (−1.40–1.30)
0.87 0.72 1.14 0.74 0.47* −0.33
(0.58–1.32) (0.06–8.32) (0.40–3.25) (0.31–1.74) (0.11–0.83) (−1.68–1.01)
a : Mean and standard deviation. ⁎: P b 0.05; ⁎⁎: P b 0.01. Significant values are in bold. ORu: odds ratio in univariate test. ORa: odds ratio in multivariate test. βu: regression coefficient in univariate test. βa: regression coefficient in multivariate test.
knowledge in both ethnic groups and improved the attitudes in Tibetan group but not in Han group, and moreover, did not change the behaviors of smoking in both ethnic groups. Our baseline data showed that smoking-related knowledge scores and attitudes scores of Tibetan students were lower, and smoking rates were higher than those of the Guangzhou Han students. This may be partially explained by the more relaxed smoking control environment in Linzhi: more than half (54%) of peers and nearly 70% of teachers smoked at school. Furthermore, without intervention, the smoking rate of Linzhi Tibetan increased significantly (control group). These findings all suggest the necessity of carrying out tobacco control intervention for adolescents in Tibetan students. Consistent to findings of other studies (Wen, Chen, & Liang, 2007), school-based intervention could improve smoking-related knowledge. As for attitudes, the intervention was more effective among Linzhi Tibetan. Students' non-significant attitudes change in Guangzhou Han was similar to the reports from Wen (Wen, Chen, & Liang, 2007) and Soldz (Soldz, Kreiner, Clark, & Krakow, 2000). These results suggest that the intervention activities have changed the attitudes of Tibetan middle school students to be more likely against smoking, whereas Guangzhou Han students' smoking attitudes not so. This difference may be partly due to a higher proportion of Linzhi Tibetan students participated in the intervention activities. In addition, before the implementation of the intervention, the school environment was more favorable for smoking in Linzhi without taking any institutional tobacco control measures; hence there is more room for smoking-related attitudes change after intervention. Students in Guangzhou, however, had
been more exposed to a tobacco-controlled environment even before the intervention and their smoking-related attitudes were harder to make a significantly different change after intervention. The intervention did not significantly affect students smoking behaviors. Other studies reported that school-based intervention could lead to a reduction in adolescent smoking prevalence (Campbell et al., 2008). A number of potential reasons may explain the overall nonsignificant effects on students smoking behavior in the current study (Thompson, McLerran, Livaudais, & Coronado, 2010). The intervention intensity was relatively low considering the number of students the intervention attempted to reach. For example, the frequency of smokingrelated health education lectures was rare (only twice). In addition, the relatively short duration of intervention activities (one year) may also affect the effectiveness of the intervention. Furthermore, the intervention effects may be weakened by a lack of supporting messages in the community which students encounter outside school, since the messages students receive at school could be undermined. Finally, effectiveness of intervention may have culture difference. In our study, intervention lead by most popular students is related to heroism, while in China people may encourage collectivism. The culture difference may result in the ineffectiveness of activities lead by peers. Similar findings of effectiveness of intervention in changing smokingrelated knowledge and attitudes whereas not in smoking-related behaviors were also reported in other studies (Soldz et al., 2000). This can be explained by the knowledge, attitude, and practice model in health education, the purpose of which is to inform people of available scientific knowledge of the disease, so that they can use this knowledge to bring
Table 4 Comparison of participation of smoking control-related intervention activities between the two intervention groups at follow-up. Intervention activities
Health Policies in School Saw or heard of regulations on smoking Health Environment in school Tobacco Control Group Saw No-smoking signs Helped smoking students quit smoking Personal Health Skills Signed signature non-smoking pledge Blackboard newsletter Class theme meetings Posters and publicity pictures Brochure Logo design contest Health education lecture No-Tobacco-Day theme activities Self-producing newspaper competition Essay competition
Linzhi Tibetan
Guangzhou Han
χ2
P
n
%
n
%
171
49.0
319
53.3
1.601
0.206
136 155 227
39.0 44.5 65.2
93 230 149
15.5 38.4 24.8
66.616 3.443 150.191
b0.001 0.064 b0.001
277 239 198 147 132 128 141 143 99 71
79.6 68.7 56.9 42.2 37.9 36.8 40.5 41.1 28.4 20.4
236 135 196 181 172 232 253 211 156 112
39.4 22.5 32.6 30.2 28.8 38.7 42.2 35.4 26.0 18.6
143.276 197.132 53.528 14.191 8.381 0.355 0.268 3.034 0.696 0.442
b0.001 b0.001 b0.001 b0.001 0.004 0.551 0.605 0.082 0.404 0.506
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about change of attitudes and practices for better health. It implies that knowledge does not necessarily lead to a change in attitudes and behaviors. Previous studies suggested that changes in attitudes and knowledge are precursors to behavior changes (Klein & Wilson, 2002; Robinson, Emmons, Moolchan, & Ostroff, 2008). Bruvold suggested that attitudes may be harder to change than knowledge (Bruvold, 1993). The present study showed that attitudes might be more difficult to change than knowledge for the Han students in Guangzhou. However, behavior change is much harder than that of knowledge and attitudes in both ethnic groups. According to behavioral theories, smoking behavior does not entirely depend on knowledge and attitudes. In contrast, many other factors, such as smoking cessation-related self-efficacy, social norms, presence of peer pressure, benefits and barriers of smoking cessation, availability of cigarettes, among others, may contribute to the change of smoking behaviors (Bian et al., 2012; Ganesh, Subba, Unnikrishna, Jain, & Badiger, 2011; Qing et al., 2011). The findings suggested that currently adopted intervention was far from effective to decrease smoking behaviors. The intervention intensity, for example, the frequency of health education lectures, Tobacco Control Group activities, could be increased. There is also need for community and family-based smoking prevention programs so that the messages about the dangers of smoking are consistent across school, home and the broader community. Intervention can also be more culture-related. Activities embody collectivism could be designed, e.g., group competition activities in smoking prevention. More pertinent interventions targeting adolescents and sensitive to ethnic and cultural differences are greatly warranted. The current study has some limitations. First, we only included two study sites and four schools, which may limit the generalization of study findings. Second, as the intervention was school-based, differences between schools existed even though some baseline differences were adjusted in the analyses. Third, intervention in this study was packaged together, so we could not identify the effectiveness of each individual intervention activity. Fourth, our study focused on school-based intervention and evaluation; hence there might be a lack of supporting messages in the environment outside school, which may weaken the effectiveness of the intervention. Finally, data were collected at baseline and at followup one year later, there was no intermediate data collection in between. 5. Conclusions The impact of this school-based smoking intervention is different among Linzhi Tibetan and Guangzhou Han students. The intervention was effective in increasing knowledge but not in the change of behavior in both Tibetan and Han ethnic groups. This intervention was more effective for Tibetan compared with the Han ethnic group. More research is needed on how interventions can be adapted to address ethnic and cultural differences. Role of Funding Sources This work was supported by a grant from China Medical Board (the grant number: CMB00729). CMB had no role in the study design, collection, analysis or interpretation of the data, writing the manuscript, or the decision to submit the paper for publication. Contributors Hao Yuantao, Chen Yan and Ling Wenhua designed the study and wrote the protocol. Chen Yan and Chen Long conducted literature searches and provided summaries of previous research studies. Chen Long conducted the statistical analysis. Chen Long, Chen Yan and Gu Jing wrote the first draft of the manuscript. Hao Yuantao, Gu Jing and Yan Guo revised the article and all authors contributed to and have approved the final manuscript. Conflict of interest All authors declare that they have no conflicts of interest. Acknowledgments We gratefully acknowledge the support of the principals of the four participating middle schools in allowing our research to be conducted and all the students and teaching staff who took part in the program so willingly. Thanks also go to: all the research assistants
who helped with the data collection and data management; and Professor Weiqing Chen who helped with the questionnaire design.
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Addictive Behaviors
Effectiveness of school-based smoking intervention in middle school students of Linzhi Tibetan and Guangzhou Han ethnicity in China Long Chen a,1, Yan Chen a,b,1, Yuantao Hao a,⁎, Jing Gu a,⁎⁎, Yan Guo a,c, Wenhua Ling d a
Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China Guangdong Institute of Public Health, Center for Disease Control and Prevention of Guangdong Province, Guangzhou 510080, China Sun Yat-sen Center for Migrant Health Policy, Guangzhou 510080, China d Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China b c
H I G H L I G H T S • • • • •
Smoking situation of Linzhi Tibetan is more serious than that of Guangzhou Han. The intervention was effective in increase of knowledge in both two ethnic groups. The intervention did not change smoking behavior in either ethnic group. The intervention changed attitude toward smoking in Tibetan but not so in Han. This intervention was more effective for Tibetan when compared with Han ethnic group.
a r t i c l e
i n f o
Keywords: School-based smoking intervention Middle school students Tibetan Han China
a b s t r a c t Purpose: The purpose of this paper is to assess the effectiveness of school-based intervention aimed to increase knowledge, to change attitudes and to reduce smoking-related behavior in both Linzhi Tibetan and Guangzhou Han middle school students in China. Design: A concurrent intervention study was conducted in both Linzhi and Guangzhou. Two schools were randomly chosen and one was randomly assigned to the intervention group and the other to the control group in both settings. Setting/participants: Participants were grade one and grade two middle school students drawn from two schools in Linzhi, Tibet Autonomous Region (southwest China) and two schools in Guangzhou, Guangdong Province (south China). Intervention: The intervention program lasted for one year and covered three aspects: health policies in school, health environment in school and personal health skills. Main outcome measures: Primary outcomes were smoking-related knowledge, attitudes and behavior (including ever smoking, daily smoking, weekly smoking and current smoking) and were measured by a self-administered questionnaire before and after the intervention. Results: This intervention increased smoking-related knowledge in both Tibetan (β = 1.32, 95% CI (0.87–1.77)) and Han ethnic groups (β = 0.47, 95% CI (0.11–0.83)). It changed attitudes toward smoking in Tibetan (β = 1.47, 95% CI (0.06–2.87)) but not so in Han (β = −0.33, 95% CI (−1.68–1.01)). The intervention changed the prevalence of smoking in neither ethnic groups (P N 0.05). Conclusions: The impact of school-based smoking intervention is different among Tibetan and Han students. This intervention was more effective for Tibetans when compared with the Han ethnic group. More research is needed on how intervention can be adapted to address ethnic and cultural differences. © 2013 Elsevier Ltd. All rights reserved.
1. Introduction ⁎ Correspondence to: H. Yuantao, School of Public Health, Sun Yat-sen University, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China. Tel./fax: +86 20 87331587. ⁎⁎ Correspondence to: G. Jing, School of Public Health, Sun Yat-sen University, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, China.Tel.: + 86 20 87331470; fax: + 86 20 87330446. E-mail addresses: [email protected] (Y. Hao), [email protected] (J. Gu). 1 Co-first author. 0306-4603/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.addbeh.2013.09.026
1.1. Smoking is a grave concern globally Health problems caused by tobacco usage are still severe (WHO, 2008, 2009c). The World Health Organization (WHO) estimates that there are about one billion smokers worldwide (WHO, 2010). Almost 6million people die from tobacco use or exposure each year, accounting
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for 6% of all female deaths and 12% of all male deaths in the world (WHO, 2009a).
1.2. Adolescent smoking status is severe Adult smoking habits are mostly formed in adolescence (Warren, Jones, Eriksen, & Asma, 2006). Monitoring the Future study in 2012 shows that 19% of 12th graders were current smokers in the U.S. (Johnston, Malley, Bachman, & Schulenberg, 2012). The European School Survey Project on Alcohol and Other Drugs (ESPAD) in 2011 shows that on average, 28% of the students in the ESPAD countries had used cigarettes during the past 30 days (Hibell et al., 2011). The Global Youth Tobacco Survey (GYTS) from Indonesia showed that 41.0% of the boys and 3.5% of the girls currently smoked cigarettes (WHO, 2009b).
1.3. Smoking status in China China is the world's largest tobacco producer, consumer and one of 14 countries of high burden of tobacco use (Hsia et al., 2010). Previous research of adolescents reported that 28% to 43% of males and 1% to 11% of females identified themselves as smokers (Chen et al., 2006). Additional data suggest that smoking rates in adolescents have been on the rise, and the age of smoking initiation is becoming younger (Zhang, Tian, Hou, & Li, 2003). Reducing the prevalence of tobacco use among adolescents remains a key public health priority in China (Hastings & Angus, 2008).
1.4. Difference exists among ethnic groups People of different ethnic groups usually have different dialects and culture, resulting in disparities in behaviors among ethnic groups (Caraballo, Yee, Gfroerer, & Mirza, 2008). Thus, the effects of the smoking intervention program may be distinct between ethnic groups. For example, one study reported that the non-Arab American students were 23% less likely to smoke cigarettes as compared to Arab American youths (Rice, Weglicki, Templin, Jamil, & Hammad, 2010). In another study, Hispanics were more likely than whites to quit smoking (Kahende, Malarcher, Teplinskaya, & Asman, 2011). China is a multi-ethnic country covering a vast territory. The Han nationality is the majority group with a population of over 1.2 billion, which accounts for 91.5% of the Chinese population. Tibetans have a population of over 5.41million, which ranks eighth among all minorities (National Bureau of Statistics of China, 2010). Few studies have examined Tibetan adolescents' smoking rate. However, one study in Linzhi, Tibet showed that 14.8% of middle school students were current cigarette smokers (Chen et al., 2010), indicating a need for greater clarity about smoking rates. Furthermore, there are no reported intervention studies targeting Tibetan adolescents' smoking status.
1.6. Purposes and hypothesis of this study The purposes of the current study are to examine the smoking status of middle school students at two sites (Linzhi and Guangzhou) between two ethnic groups (Tibetan and Han), and to compare the effectiveness of the intervention among students of these two ethnics groups. We hypothesize that the intervention is effective in controlling and preventing smoking in both locations and that the size of the effect vary depending on distinct ethnic characteristics.
2. Methods 2.1. Settings The study was conducted in Linzhi of Tibet Autonomous Region (southwest China) and Guangzhou of Guangdong Province (south China). Linzhi is located in the southeast of Tibet Autonomous Region with a total population of 140,000, of which more than 90% are Tibetans. Guangzhou is the capital city of Guangdong Province with a population of 12.7 million, the majority of which is Han.
2.2. Study design A school-based intervention study was conducted from September 2008 to September 2009 in both Linzhi and Guangzhou, with intervention group and control group at each site. School-based tobacco control intervention was given to the intervention group while no specific intervention was given to the control group. Differences in attitudes, knowledge and behaviors between the intervention and control groups were compared each site separately before and after the intervention. In addition, the intervention effects between the two study sites were compared.
2.3. Participants Participants of the study were first and second year middle school students. Randomization occurred at the school level to avoid contamination between groups. Two out of seven middle schools were randomly selected in Linzhi and two were randomly selected in Guangzhou. The two chosen schools of each site were then randomly assigned to the intervention or control group. All students of first and second years of the selected schools (712 in Linzhi and 1,105 in Guangzhou) were invited and all of them agreed to participate in the study. Written informed consent was obtained from school teachers and verbal informed consent was obtained from the students. Approval for the design and data collection procedures was obtained beforehand from the ethic committee of the School of Public Health, Sun Yat-sen University.
2.4. Data collection 1.5. Background on school-based smoking intervention School-based smoking intervention programs are considered to be one of the most effective strategies for reducing smoking prevalence among adolescents (Gingiss, Roberts-Gray, & Boerm, 2006). Such programs aim at providing smoking-related health information, and pursue strategies based on social competence or social influence (Wiehe, Garrison, Christakis, Ebel, & Rivara, 2005). School-based smoking intervention programs have shown evidence to improve adolescents' smoking knowledge, attitudes (Lee, Wu, Lai, & Chu, 2007; Park, 2006) and decrease smoking behaviors both in China and globally (Chen, Fang, Li, Stanton, & Lin, 2006; Sun, Miyano, Rohrbach, Dent, & Sussman, 2007).
Questionnaire surveys were conducted on all study objects before and after the intervention (i.e., the baseline survey in September 2008 and the follow-up survey in September 2009). Research assistants were recruited from the school of public health at the medical colleges at each site and received trainings on how to collect data and perform quality control. Surveys were completed in classrooms under supervision of qualified research assistants. Pre-post surveys were anonymous, and matched on sex, school, ethnicity, first letters of family name and first name. Pre-post surveys which could not be matched were excluded. A total of 709 and 1098 matched questionnaires were collected in Linzhi (correspondence rate 99.6%) and Guangzhou (correspondence rate 99.4%) respectively.
L. Chen et al. / Addictive Behaviors 39 (2014) 189–195
2.5. Intervention The contents of intervention were designed according to the literature of successful interventions in adolescents' tobacco control (Lawrence & Marshall, 1991; Wen, Chen, & Liang, 2007; Wen et al., 2007; WHO, 1995). In this study, the intervention targeted at students and teachers in the school. The preliminary list of intervention activities was generated by a panel of health education experts, after a critical review of Chinese and English literature. Then this list was revised after in-depth interviews with school administrators to ensure feasibility. Focus group discussions with smoking students were also held to discuss the acceptability of interventions. Families were not involved because most of the Tibetan students live in school. The intervention program lasted for an entire school year and covered following aspects: (1) Health Policies in School. In the two intervention schools, a tobacco control committees headed by the principal was established respectively; regulations on smoking were made at the beginning of the study (“e.g., No smoking was allowed in school”). (2) Health Environment in school. 30 no-smoking signs were placed in the school yards. Peer education was conducted to help smokers to quit smoking. Peer educators were the most popular students elected by classmates and received special trainings on smoking prevention-related knowledge and communication skills. At least once during the study period, peer educators shared smoking-related knowledge with each smoker in his/her class, encouraged them to quit, and not to give or accept cigarettes during social activities. The peer educators were also core members of the Tobacco Control Group. Under the help of teachers, they organized group activities quarterly to discuss harms of smoking to one's health, to share knowledge of smoking prevention with students in each class. There were 20 groups in Linzhi and 26 groups in Guangzhou. Teachers were required not to smoke in front of students. (3) Personal Health Skills. Brochures of health hazards of smoking were issued to all participants twice (October 2008 and March 2009). Blackboard newsletter (chalk board at the back of the classroom for information sharing), class theme meetings of smoking control, posters and publicity pictures were made and renewed quarterly. Smoking-related health education lectures were given twice (November 2008 and April 2009). Students participated in smokingcessation related activities including essay competitions, signing for non-smoking pledge, No-Tobacco-Day theme activities, selfproducing newspaper competition and logo design contests.
2.6. Measurements Background characteristics of all students (sex, age, nationality, school and grade) were collected. Students' smoking-related knowledge, attitudes and behaviors were measured by scales which were revised from Guangzhou City Middle School Students Smoking Status Questionnaire developed by Chen and his colleagues (Wen, Chen, & Lu, 2005, 2006). Questions regarding smoking in school included smoking status of peers and teachers, whether students' smoking was permitted by teachers and parents, tobacco control advocacy and tobacco control activities in the schools, and passive smoking at schools. Smoking-related knowledge was measured by 20 items (e.g., “whether passive smoking is harmful to the body?”). Knowledge score was calculated by summing up correct individual item responses. Smoking-related attitudes consisted of 18 items (e.g., “Not accept others' cigarette is impolite”). The answers ranged from “strongly disagree” (=1) to “strongly agree” (=5). The attitudes score was a sum of 18 items, with a higher score indicating more negative attitudes towards smoking. Evaluation of psychometric features was acceptable (Cronbach's alpha = 0.86, RMSEA = 0.05, CFI = 0.98).
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Smoking behaviors included whether a person smoked, smoked daily, smoked weekly, or is smoking currently (WHO, 1982; Zheng, 1992). Ever smoking was defined as having ever used cigarettes, even one or two times. Weekly smoking was defined as smoking at least one cigarette per week, which continued or was cumulating for three months or more, but cannot meet the daily smoker's standard. Daily smoking was defined as smoking at least one cigarette per day, which continued or was cumulating for three months or more. Current smoking was defined as smoking one or more cigarettes in the past 30 days.
2.7. Statistical analysis Descriptive analysis and univariate analysis were conducted to test whether the background characteristics (age, sex, and grade) were balanced between the intervention and control groups. Possible confounders were adjusted in the subsequent multivariate analyses. The association between follow-up smoking status (dependent variable, yes vs. no) and intervention (independent variable, yes vs. no) was analyzed by using unconditional logistic regression models. Similarly, the associations between follow-up knowledge/attitude (dependent variable) and intervention (independent variable) were analyzed by using linear regression models. To compare the differences in the effects of the intervention between Linzhi Tibetan and Guangzhou Han, the significance of moderating (interaction) effects of region on the association between intervention and outcomes were tested by using multivariate regression models, each including region, intervention, region*intervention and adjusting for baseline confounders. Effect size (Cohen's d) was defined as the difference in the change of prevalence or mean scores between the intervention and control groups divided by the pooled standard deviation (Cohen, 1988). SPSS (version 17.0) was used for all the statistical analyses. Statistical significance was determined at the P b 0.05 level.
3. Result 3.1. Baseline status of all participants Of all the students, the average age was 14.5 ± 1.1 years old, with 50.4% being boys. The intervention group in Linzhi (14.8 ± 1.4 years old) was slightly younger than the control group (15.1 ± 1.2 years old), while in Guangzhou, there were differences in sex and age between the intervention and control groups. The intervention and control groups in Linzhi were comparable in smoking behaviors but not in knowledge and attitudes. In Guangzhou, the intervention and control groups were comparable in smoking behaviors and knowledge but not in attitudes (Table 1). Tibetan students had lower scores in smoking-related knowledge (5.0 ± 3.0 vs. 7.3 ± 3.0, P b 0.001) and attitudes (67.2 ± 9.6 vs. 76.8 ± 10.1, P b 0.001) but higher rates of smoking behavior (ever smoking 33.1%, weekly smoking 1.8%, daily smoking 8.5%, and current smoking 11.4%) than Han students (7.5%, 0.3%, 0.5% and 1.1%, respectively, P b 0.05). Significance differences existed between the two ethnic groups in age and sex.
3.2. Self-reported differences in smoking-related environment between Linzhi Tibetans and Guangzhou Han at baseline As shown in Table 2, compared to their counterparts in Guangzhou, in Linzhi, a higher proportion of peers and teachers smoked in school; a higher proportion of students perceived there was someone smoking in school and were allowed to smoke by their parents or teachers; and a lower proportion reported there were health-related advocacy posters or blackboard newsletters in school.
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Table 1 Baseline Comparisons of students of the four schools in Linzhi and Guangzhou. Linzhi Tibetan Total
Sex⁎ Male Female Agea⁎ Grade One Two Smoking-related knowledgea⁎ Smoking-related attitudes a⁎ Smoking-related behavior Ever smoking ⁎ Weekly smoking⁎ Daily smoking ⁎ Current smoking ⁎
Guangzhou Han Intervention
Control
(n = 709)
(n = 349)
(n = 360)
n (%)
n (%)
n (%)
P
306 403 15.0
(43.2) (56.8) (1.3)
155 194 14.8
(44.4) (55.6) (1.4)
151 209 15.1
(41.9) (58.1) (1.2)
0.507
394 315 5.0 67.2
(55.6) (44.4) (3.0) (9.6)
200 149 4.4 65.7
(57.3) (42.7) (2.6) (9.5)
194 166 5.5 68.8
(53.9) (46.1) (3.3) (9.4)
0.360
235 13 60 81
(33.1) (1.8) (8.5) (11.4)
123 4 35 41
(35.2) (1.1) (10.0) (11.7)
112 9 25 40
(31.1) (2.5) (6.9) (11.1)
Total
Intervention
Control
(n = 1,098)
(n = 592)
(n = 506)
n (%)
n (%)
n (%)
P
604 494 14.2
(55.0) (45.0) (0.8)
308 284 14.3
(52.0) (48.0) (0.9)
296 210 14.2
(58.5) (41.5) (0.8)
b0.001 b0.001
582 516 7.3 76.8
(53.0) (47.0) (3.0) (10.1)
300 292 7.4 75.9
(50.7) (49.3) (3.0) (9.9)
282 224 7.2 77.9
(55.7) (44.3) (2.9) (10.2)
0.296 b0.001
0.243 0.179 0.140 0.790
82 3 5 12
(7.5) (0.3) (0.5) (1.1)
52 2 2 8
(8.8) (0.3) (0.3) (1.4)
30 1 3 4
(5.9) (0.2) (0.6) (0.8)
0.073 1.000 0.666 0.373
0.020
0.032 0.002 0.094
a : Mean and standard deviation. *: There is statistically significant differences between Linzhi District Tibetan and Guangzhou Han (combining the intervention and control groups) (P b 0.05).
3.3. Effectiveness of intervention on smoking-related knowledge and attitudes score In Linzhi, after adjusting for baseline confounders, students of the intervention group had higher scores of smoking-related knowledge (βa = 1.32, 95%CI = 0.87–1.77, P b 0.001) and smoking-related attitudes (βa = 1.47, 95%CI 0.06–2.87, P = 0.041) than those of the control group after intervention. In Guangzhou, using similar methods, the intervention group had higher scores of smoking-related knowledge (βa = 0.47, 95%CI 0.11–0.83, P = 0.010) but similar scores of smokingrelated attitudes (βa = −0.33, 95%CI = 1.68–1.01, P = 0.625) as compared to the control group. The effect size of the intervention on knowledge scores in Linzhi was 0.54 while it was 0.08 in Guangzhou (data not tabulated).
3.4. Effectiveness of intervention on smoking behavior In Linzhi, the pre-post test showed that the increment of current smoking rate (but not the other three smoking behaviors) in control group was significant (from 11.1% to 18.1% P b 0.01). None of the smoking rates changed significantly in the intervention group. In Guangzhou, the differences of changes of all four smoking-related behaviors in both intervention and control groups were not significant. In Linzhi, after the intervention, none of the four smoking behaviors indicators was significantly different between the intervention and control groups after adjusting for baseline confounders. Similar findings were revealed for those in Guangzhou (Table 3).
3.5. Moderating effects of region on intervention The moderating effect of region was significant for the association between intervention and smoking-related knowledge: βa of the interaction term (region*intervention) was −0.22 (95%CI = −1.39 to −0.24, P = 0.005). Similar finding was found for smoking-related attitudes (βa of the interaction term was −0.16, 95% CI = −4.04 to −0.04, P = 0.045). The moderating effects of region were non-significant for the association between intervention and all studied smoking-related behaviors (adjusted odds ratios ranged from 1.42 to 5.06, P N 0.05) (data not tabulated). 3.6. Participation of the intervention of the two intervention groups Of all intervention activities, the participation rates ranged from 20.4% (essay competition) to 68.7% (blackboard newsletter) in Linzhi. In Guangzhou, the participation rates were from 15.5% (Tobacco Control Group) to 53.3% (saw or heard of regulations on smoking). The Linzhi Tibetan had higher participation rates than Guangzhou Han in many intervention activities (Table 4). 4. Discussion In this school-based pilot study, the effectiveness of the one-year intervention was assessed on aspects of smoking-related behaviors, knowledge and attitudes. The results showed that the smoking situation of middle school students of Linzhi, Tibet was more serious than that of their counterparts of Guangzhou Han. The intervention increased the
Table 2 Differences in smoking-related environment in school between Linzhi Tibetans and Guangzhou Han at baseline.
Peers/teachers smoke in school Peers Head teachers Other teachers Peers or teachers Passive smoking in school Smoking in school is permitted by teachers One's smoking in school is permitted by parents Tobacco control-related advocacy posters Tobacco control-related activities organized by school
Linzhi Tibetans (%)
Guangzhou Han (%)
χ2
P
54.0 20.7 68.9 88.4 44.7 6.1 8.3 32.7 28.4
28.7 6.6 49.6 74.8 32.8 2.8 2.5 37.8 29.8
184.3 125.4 103.6 81.6 40.9 19.3 50.8 7.5 0.7
b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 0.006 0.405
L. Chen et al. / Addictive Behaviors 39 (2014) 189–195
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Table 3 Effects of interventions on students' smoking behaviors and scores of attitudes and knowledge. Linzhi Tibetan (%)
Ever smoking Weekly smoking Daily smoking Current smoking Knowledge score Attitudes score
Intervention group (%)
Control group (%)
33.2 2.3 7.5 16.3 9.1 ± 3.1a 70.0 ± 9.7a
33.6 4.2 11.1 18.1 7.9 ± 2.8 a 68.1 ± 8.0a
Guangzhou Han (%) Univariate
Adjusted
ORu/βu
95%CI
ORa/βa
95%CI
1.02 1.85 1.55 1.13 1.19 ** 1.86*
(0.74–1.39) (0.78–4.43) (0.93–2.61) (0.76–1.67) (0.75–1.63) (0.50–3.22)
0.97 1.63 1.43 1.03 1.32** 1.47*
(0.71–1.33) (0.67–3.95) (0.82–2.47) (0.69–1.53) (0.87–1.77) (0.06–2.87)
Intervention group (%)
Control group (%)
9.6 0.3 1.4 2.4 11.6 ± 2.8a 77.6 ± 10.5a
9.1 0.2 1.4 1.8 11.1 ± 3.2a 77.7 ± 11.6a
Univariate
Adjusted
ORu/βu
95%CI
ORa/βa
95%CI
0.94 0.58 1.02 0.75 0.51 * −0.05
(0.62–1.41) (0.05–6.46) (0.37–2.84) (0.32–1.74) (0.15–0.87) (−1.40–1.30)
0.87 0.72 1.14 0.74 0.47* −0.33
(0.58–1.32) (0.06–8.32) (0.40–3.25) (0.31–1.74) (0.11–0.83) (−1.68–1.01)
a : Mean and standard deviation. ⁎: P b 0.05; ⁎⁎: P b 0.01. Significant values are in bold. ORu: odds ratio in univariate test. ORa: odds ratio in multivariate test. βu: regression coefficient in univariate test. βa: regression coefficient in multivariate test.
knowledge in both ethnic groups and improved the attitudes in Tibetan group but not in Han group, and moreover, did not change the behaviors of smoking in both ethnic groups. Our baseline data showed that smoking-related knowledge scores and attitudes scores of Tibetan students were lower, and smoking rates were higher than those of the Guangzhou Han students. This may be partially explained by the more relaxed smoking control environment in Linzhi: more than half (54%) of peers and nearly 70% of teachers smoked at school. Furthermore, without intervention, the smoking rate of Linzhi Tibetan increased significantly (control group). These findings all suggest the necessity of carrying out tobacco control intervention for adolescents in Tibetan students. Consistent to findings of other studies (Wen, Chen, & Liang, 2007), school-based intervention could improve smoking-related knowledge. As for attitudes, the intervention was more effective among Linzhi Tibetan. Students' non-significant attitudes change in Guangzhou Han was similar to the reports from Wen (Wen, Chen, & Liang, 2007) and Soldz (Soldz, Kreiner, Clark, & Krakow, 2000). These results suggest that the intervention activities have changed the attitudes of Tibetan middle school students to be more likely against smoking, whereas Guangzhou Han students' smoking attitudes not so. This difference may be partly due to a higher proportion of Linzhi Tibetan students participated in the intervention activities. In addition, before the implementation of the intervention, the school environment was more favorable for smoking in Linzhi without taking any institutional tobacco control measures; hence there is more room for smoking-related attitudes change after intervention. Students in Guangzhou, however, had
been more exposed to a tobacco-controlled environment even before the intervention and their smoking-related attitudes were harder to make a significantly different change after intervention. The intervention did not significantly affect students smoking behaviors. Other studies reported that school-based intervention could lead to a reduction in adolescent smoking prevalence (Campbell et al., 2008). A number of potential reasons may explain the overall nonsignificant effects on students smoking behavior in the current study (Thompson, McLerran, Livaudais, & Coronado, 2010). The intervention intensity was relatively low considering the number of students the intervention attempted to reach. For example, the frequency of smokingrelated health education lectures was rare (only twice). In addition, the relatively short duration of intervention activities (one year) may also affect the effectiveness of the intervention. Furthermore, the intervention effects may be weakened by a lack of supporting messages in the community which students encounter outside school, since the messages students receive at school could be undermined. Finally, effectiveness of intervention may have culture difference. In our study, intervention lead by most popular students is related to heroism, while in China people may encourage collectivism. The culture difference may result in the ineffectiveness of activities lead by peers. Similar findings of effectiveness of intervention in changing smokingrelated knowledge and attitudes whereas not in smoking-related behaviors were also reported in other studies (Soldz et al., 2000). This can be explained by the knowledge, attitude, and practice model in health education, the purpose of which is to inform people of available scientific knowledge of the disease, so that they can use this knowledge to bring
Table 4 Comparison of participation of smoking control-related intervention activities between the two intervention groups at follow-up. Intervention activities
Health Policies in School Saw or heard of regulations on smoking Health Environment in school Tobacco Control Group Saw No-smoking signs Helped smoking students quit smoking Personal Health Skills Signed signature non-smoking pledge Blackboard newsletter Class theme meetings Posters and publicity pictures Brochure Logo design contest Health education lecture No-Tobacco-Day theme activities Self-producing newspaper competition Essay competition
Linzhi Tibetan
Guangzhou Han
χ2
P
n
%
n
%
171
49.0
319
53.3
1.601
0.206
136 155 227
39.0 44.5 65.2
93 230 149
15.5 38.4 24.8
66.616 3.443 150.191
b0.001 0.064 b0.001
277 239 198 147 132 128 141 143 99 71
79.6 68.7 56.9 42.2 37.9 36.8 40.5 41.1 28.4 20.4
236 135 196 181 172 232 253 211 156 112
39.4 22.5 32.6 30.2 28.8 38.7 42.2 35.4 26.0 18.6
143.276 197.132 53.528 14.191 8.381 0.355 0.268 3.034 0.696 0.442
b0.001 b0.001 b0.001 b0.001 0.004 0.551 0.605 0.082 0.404 0.506
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about change of attitudes and practices for better health. It implies that knowledge does not necessarily lead to a change in attitudes and behaviors. Previous studies suggested that changes in attitudes and knowledge are precursors to behavior changes (Klein & Wilson, 2002; Robinson, Emmons, Moolchan, & Ostroff, 2008). Bruvold suggested that attitudes may be harder to change than knowledge (Bruvold, 1993). The present study showed that attitudes might be more difficult to change than knowledge for the Han students in Guangzhou. However, behavior change is much harder than that of knowledge and attitudes in both ethnic groups. According to behavioral theories, smoking behavior does not entirely depend on knowledge and attitudes. In contrast, many other factors, such as smoking cessation-related self-efficacy, social norms, presence of peer pressure, benefits and barriers of smoking cessation, availability of cigarettes, among others, may contribute to the change of smoking behaviors (Bian et al., 2012; Ganesh, Subba, Unnikrishna, Jain, & Badiger, 2011; Qing et al., 2011). The findings suggested that currently adopted intervention was far from effective to decrease smoking behaviors. The intervention intensity, for example, the frequency of health education lectures, Tobacco Control Group activities, could be increased. There is also need for community and family-based smoking prevention programs so that the messages about the dangers of smoking are consistent across school, home and the broader community. Intervention can also be more culture-related. Activities embody collectivism could be designed, e.g., group competition activities in smoking prevention. More pertinent interventions targeting adolescents and sensitive to ethnic and cultural differences are greatly warranted. The current study has some limitations. First, we only included two study sites and four schools, which may limit the generalization of study findings. Second, as the intervention was school-based, differences between schools existed even though some baseline differences were adjusted in the analyses. Third, intervention in this study was packaged together, so we could not identify the effectiveness of each individual intervention activity. Fourth, our study focused on school-based intervention and evaluation; hence there might be a lack of supporting messages in the environment outside school, which may weaken the effectiveness of the intervention. Finally, data were collected at baseline and at followup one year later, there was no intermediate data collection in between. 5. Conclusions The impact of this school-based smoking intervention is different among Linzhi Tibetan and Guangzhou Han students. The intervention was effective in increasing knowledge but not in the change of behavior in both Tibetan and Han ethnic groups. This intervention was more effective for Tibetan compared with the Han ethnic group. More research is needed on how interventions can be adapted to address ethnic and cultural differences. Role of Funding Sources This work was supported by a grant from China Medical Board (the grant number: CMB00729). CMB had no role in the study design, collection, analysis or interpretation of the data, writing the manuscript, or the decision to submit the paper for publication. Contributors Hao Yuantao, Chen Yan and Ling Wenhua designed the study and wrote the protocol. Chen Yan and Chen Long conducted literature searches and provided summaries of previous research studies. Chen Long conducted the statistical analysis. Chen Long, Chen Yan and Gu Jing wrote the first draft of the manuscript. Hao Yuantao, Gu Jing and Yan Guo revised the article and all authors contributed to and have approved the final manuscript. Conflict of interest All authors declare that they have no conflicts of interest. Acknowledgments We gratefully acknowledge the support of the principals of the four participating middle schools in allowing our research to be conducted and all the students and teaching staff who took part in the program so willingly. Thanks also go to: all the research assistants
who helped with the data collection and data management; and Professor Weiqing Chen who helped with the questionnaire design.
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