***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PROBLEM Tobacco use is a major contributor to deaths from chronic diseases . The findings from the Global Youth Tobacco Survey ( GYTS ) suggest that the estimate of a doubling of deaths from smoking ( from 5 million per year to approximately 10 million per year by 2020 ) might be an underestimate because of the increase in smoking among young girls compared with adult females , the high susceptibility of smoking among never smokers , high levels of exposure to secondh and smoke , and protobacco indirect advertising . REPORTING PERIOD COVERED This report includes GYTS data collected during 2000 - 2007 from 140 World Health Organization ( WHO ) member states , six territories ( American Samoa , British Virgin Isl and s , Guam , Montserrat , Puerto Rico , and the U.S. Virgin Isl and s ) , two geographic regions ( Gaza Strip and West Bank ) , one United Nations administered province ( Kosovo ) , one special administrative region ( Macau ) , and one Commonwealth ( Northern Mariana Isl and s ) . For countries that have repeated GYTS , only the most recent data are included . For countries with multiple survey sites , only data from the capital or largest city are presented . DESCRIPTION OF SYSTEM GYTS is a school-based survey of a defined geographic site that can be a country , a province , a city , or any other geographic entity . GYTS uses a st and ardized methodology for constructing sampling frames , selecting schools and classes , preparing question naires , conducting field procedures , and processing data . GYTS st and ard sampling methodology uses a two-stage cluster sample design that produces sample s of students in grade s associated with students aged 13 - 15 years . Each sampling frame includes all schools ( usually public and private ) in a geographically defined area containing any of the identified grade s. In the first stage , the probability of schools being selected is proportional to the number of students enrolled in the specified grade s. In the second sampling stage , classes within the selected schools are selected r and omly . All students in selected classes attending school the day the survey is administered are eligible to participate . Student participation is voluntary and anonymous using self-administered data collection procedures . The GYTS sample design produces independent , cross-sectional estimates that are representative of each site . RESULTS The findings in this report indicate that the level of cigarette smoking between boys and girls is similar in many sites ; the prevalence of cigarette smoking and use of other tobacco products is similar ; and susceptibility to initiate smoking among never smokers is similar among boys and girls and is higher than cigarette smoking in the majority of sites . Approximately half of the students reported that they were exposed to secondh and smoke in public places during the week preceding the survey . Approximately eight in 10 favor a ban on smoking in public places . Approximately two in 10 students own an object with a cigarette br and logo on it , and one in 10 students have been offered free cigarettes by a tobacco company representative . Approximately seven in 10 students who smoke reported that they wanted to stop smoking . Approximately seven in 10 students who smoked were not refused purchase of cigarettes from a store during the month preceding the survey . Finally , approximately six in 10 students reported having been taught in school about the harmful effects of smoking during the year preceding the survey . INTERPRETATION The findings in this report suggest that interventions that decrease tobacco use among youth ( e.g. , increasing excise taxes , media campaigns , school programs in conjunction with community interventions , and community interventions that decrease minors ' access to tobacco ) must be broad-based , focused on boys and girls , and have components directed toward prevention and cessation . If effective programs are not developed and implemented soon , future morbidity and mortality attributed to tobacco probably will increase . PUBLIC HEALTH ACTION The synergy between countries in passing tobacco-control laws , regulations , or decrees ; ratifying the WHO Framework Convention on Tobacco Control ; and conducting GYTS offers a unique opportunity to develop , implement , and evaluate comprehensive tobacco-control policy that can be helpful to each country . The challenge for each country is to develop , implement , and evaluate a tobacco-control program and make changes where necessary This study reports the evaluation of an intervention design edto reinforcetobacco abstinence amongelementary schoolchildren in a school transition period . This intervention was developed according to the principles of Intervention Mapping . A total of 765 grade 5 students ( ages 10 - 12 ) was recruited in 32 elementary schools . A quasi-experimental longitudinal design was used to evaluate the outcomes . Results observed 2 and 8 months postintervention are reported here . It is shown that although the behavior remained largely unchanged by the intervention , some of its determinants were modified . Behavioral intention , behavioral and normative beliefs , perceived self-efficacy , and role beliefs were changed at one or both postintervention measures . An interesting feature of these results relates to the fact that the most positive outcomes were seen among at-risk children . Discussion considers the advisability to develop , implement , and evaluate evidence -based interventions targeting the psychosocial factors underlying maintenance of tobacco smoking abstinence in elementary school Most school-based smoking prevention studies employ design s in which schools or classrooms are assigned to different treatment conditions while observations are made on individual students  . This design requires that the treatment effect be assessed against the between-school variance . However , the between-school variance is usually larger than the variance that would be obtained if students were individually r and omized to different conditions . Consequently , the power of the test for a treatment effect is reduced , and it becomes difficult to detect important treatment effects . To assess the potential loss of power or to calculate appropriate sample sizes , investigators need good estimates of the intraclass correlations for the variables of interest . The authors calculated intraclass correlations for some common outcome variables in a school-based smoking prevention study , using a three-level model-i.e . , students nested within classrooms and classrooms nested within schools . The authors present the intraclass correlation estimates for the entire data set , as well as separately by sex and ethnicity . They also illustrate the use of these estimates in the planning of future studies Bruno Giraudeau and Philippe Ravaud discuss the difficulties in preventing selection bias and applying intention-to-treat analysis in cluster r and omized trials , and propose some solutions SMILES PLUS was the first study to extend the clinician-delivered logic model to prevention of tobacco use among adolescents . This multi-site trial with 154 participating offices , based on social learning theory and a behavioral ecological model , was design ed to test whether orthodontists can prevent preteens from initiating smoking . The study found that orthodontists do not automatically adhere to anti-tobacco prevention services . Social learning variables can enhance both adherence to counseling guidelines and content of counseling to increase prevention effects . Providing financial incentives , tracking prescriptions , prompting positive feedback from patients , and adopting anti-tobacco counseling models in the office are likely to enhance anti-tobacco preventive services . Training orthodontists to be comfortable when advising nonsmoking youth not to start and to use social consequences to justify youth avoidance of tobacco might increase adherence to protocol s and make their counseling more powerful .  Adolescent smokers prior to intervention were more likely to start other risky behaviors later . Preventing tobacco use may halt additional risk behaviors and thereby reduce morbidity/mortality even more than expected from tobacco control alone . New and refined clinical trials should be conducted to determine the most effective interventions for adolescent tobacco control by clinicians BACKGROUND The 1985 Minnesota Legislature established guidelines for school-based tobacco-use prevention programming and provided financial incentives to school districts to encourage them to adopt a broad range of preventive measures . The Minnesota-Wisconsin Adolescent Tobacco-Use Research Project was funded by the National Cancer Institute in 1986 to evaluate the Minnesota initiative through two parallel studies . METHODS The Four Group Comparison Study was a prospect i ve study of 48 school " units " which were r and omly assigned to one of four conditions in 1987 . Baseline observations were taken in the sixth grade in 1987 , interventions were delivered in the seventh grade , and follow-up observations were taken in the seventh , eighth , and ninth grade s. The Four Group Comparison Study was design ed to evaluate the three middle-school interventions that were most widely adopted by Minnesota school districts as a result of the 1985 legislation . The Two State Comparison Study was a serial cross-sectional study of representative districts in Minnesota and Wisconsin . Annual surveys of ninth grade rs were conducted from 1986 - 1990 . The Two State Comparison Study was design ed to determine whether tobacco-use patterns changed in Minnesota relative to Wisconsin following the Minnesota legislation . RESULTS The prospect i ve study indicated that none of the interventions was more effective in reducing adolescent tobacco use compared with a r and omized control group . The serial cross-sectional study revealed that there was a modest net decline in Minnesota relative to Wisconsin from 1986 to 1990 , but that it was within the range of chance variation . CONCLUSIONS Taken together , these results indicate that this legislative initiative was insufficient to reduce  adolescent tobacco use statewide during the 5-year study period . Together with results from other recent studies , they suggest that even more intensive efforts may be required to effect widespread reductions in adolescent tobacco use BACKGROUND Smoking is the leading preventable cause of premature death in the United States . Previous studies of financial incentives for smoking cessation in work setting s have not shown that such incentives have significant effects on cessation rates , but these studies have had limited power , and the incentives used may have been insufficient . METHODS We r and omly assigned 878 employees of a multinational company based in the United States to receive information about smoking-cessation programs ( 442 employees ) or to receive information about programs plus financial incentives ( 436 employees ) . The financial incentives were $ 100 for completion of a smoking-cessation program , $ 250 for cessation of smoking within 6 months after study enrollment , as confirmed by a biochemical test , and $ 400 for abstinence for an additional 6 months after the initial cessation , as confirmed by a biochemical test . Individual participants were stratified according to work site , heavy or nonheavy smoking , and income . The primary end point was smoking cessation 9 or 12 months after enrollment , depending on whether initial cessation was reported at 3 or 6 months . Secondary end points were smoking cessation within the first 6 months after enrollment and rates of participation in and completion of smoking-cessation programs . RESULTS The incentive group had significantly higher rates of smoking cessation than did the information-only group 9 or 12 months after enrollment ( 14.7 % vs. 5.0 % , P<0.001 ) and 15 or 18 months after enrollment ( 9.4 % vs. 3.6 % , P<0.001 ) . Incentive-group participants also had significantly higher rates of enrollment in a smoking-cessation program ( 15.4 % vs. 5.4 % , P<0.001 ) , completion of a smoking-cessation program ( 10.8 % vs. 2.5 % , P<0.001 ) , and smoking cessation within the first 6 months after enrollment ( 20.9 % vs. 11.8 % , P<0.001 ) . CONCLUSIONS In this study of employees of one large company , financial incentives for smoking cessation significantly increased the rates of smoking cessation . ( Clinical Trials.gov number , NCT00128375 . The Consoli date d St and ards of Reporting Trials ( CONSORT ) statement was developed to improve the reporting of r and omised controlled trials . It was initially published in 1996 and focused on the reporting of parallel group r and omised controlled trials . The statement was revised in 2001 , with a further up date in 2010 . A separate CONSORT statement for the reporting of abstract s was published in 2008 . In earlier papers we considered the implication s of the 2001 version of the CONSORT statement for the reporting of cluster r and omised trial . In this paper we provide up date d and extended guidance , based on the 2010 version of the CONSORT statement and the 2008 CONSORT statement for the reporting of abstract s. Objective : To assess the effect of an antismoking intervention focusing on adolescents in lower education . Students with lower education smoke more often and perceive more positive norms , and social pressure to smoke , than higher educated students . An intervention based on peer group pressure and social influence may therefore be useful to prevent smoking among these students . Design : Group r and omised controlled trial . Setting : 26 Dutch schools that provided junior secondary education . Subjects : 1444 students in the intervention and 1118 students in the control group , all in the first grade , average age 13 years . Intervention : Three lessons on knowledge , attitudes , and social influence , followed by a class agreement not to start or to stop smoking for five months and a class based competition . Main outcome measures : Comparison of smoking status before and immediately after and one year after the intervention , using multilevel analysis . Results : In the intervention group , 9.6 % of non-smokers started to smoke , in the control group 14.2 % . This leads to an odds ratio of 0.61 ( 95 % CI= 0.41 to 0.90 ) to uptake smoking in the intervention group compared with the control group . One year after the intervention , the effect was no longer significant . Conclusions : In the short-term , an intervention based on peer pressure decreases the proportion of adolescents with lower education who start smoking . Influencing social norms and peer pressure would therefore be a promising strategy in terms of preventing smoking among adolescents . The results also suggest that additional interventions in later years are needed to maintain the effect OBJECTIVES This study examined the effect of an orthodontist-delivered tobacco-use prevent 
    Output:
    
The very limited evidence currently available suggests that incentive programmes do not prevent  smoking initiation among youth .
It is therefore possible that other incentive programmes could be more successful at preventing smoking uptake in young people .