***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: Reports of cluster r and omised trials require additional information to allow readers to interpret them accurately The effective reporting of r and omised controlled trials has received useful attention in recent years . Many journals now require that reports conform to the guidelines in the Consoli date d St and ards of Reporting Trials ( CONSORT ) statement , first published in 1996 and revised in 2001 . The statement includes a checklist of items that should be included in the trial report . These items are evidence based whenever possible and are regularly review ed . The statement also recommends including a flow diagram to show the flow of participants from group assignment through to the final analysis . The CONSORT statement focused on reporting parallel group r and omised trials in which individual participants are r and omly assigned to study groups . However , in some situations it is preferable to r and omly assign groups of individuals ( such as families or medical practice s ) rather than individuals . Reasons include the threat of contamination of some interventions ( such as dietary interventions ) if individual r and omisation is used . 5 Also , in certain setting s r and omisation by group may be the only feasible method of conducting a trial . Trials with this design are variously known as field trials , community based trials , place based trials , or ( as in this paper ) cluster r and omised trials . In an earlier discussion paper we considered the implication s of the CONSORT statement for the reporting of cluster r and omised trials . Here we present up date d guidance , based on the 2001 revision of the CONSORT statement 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 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 . 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 prevention program for adolescents . METHODS Southern California orthodontic offices were r and omly assigned to experimental ( n = 77 ) and control ( n = 77 ) groups . R and omly selected adolescents were interviewed at baseline and 2 years later ( n = 15,644 ) . Experimental offices received tobacco prevention training , anti-tobacco material s , and 50 cents for each anti-tobacco " prescription " written . RESULTS The 30-day tobacco use 2-year incidence rates for the control and experimental groups were 12.6 % and 12.0 % , respectively ; incidence rates for using tobacco more than 100 times were 7.6 % and 6.8 % . Differences between the groups did not reach significance . Mean prescription compliance was 64.4 % . A multivariate logistic model , showed a significant dose response : patients who received more prescriptions had lower incidence rates than those who received few or none ( 10 % vs 14 % ) . CONCLUSIONS Training , payment , and support did not ensure clinician compliance with prevention services . The dose effect suggests that replication under conditions that would ensure clinician compliance and statistical power would more thoroughly test clinicians ' ability to prevent tobacco use OBJECTIVES We assessed the effectiveness of a 2-year multicomponent , school-based intervention design ed to reduce tobacco use rates among adolescents in an urban area of India . METHODS Students from 32 schools in Delhi and Chennai , India , were recruited and r and omly assigned to an intervention or control group . Baseline , intermediate , and outcome data were collected from 2 cohorts of 6th- and 8th- grade students in 2004 ; 14,063 students took part in the study and completed a survey in 2004 , 2005 , or 2006 . The intervention consisted of behavioral classroom curricula , school posters , a parental involvement component , and peer-led activism . The main outcome measures were self-reported use of cigarettes , bidis ( small h and -rolled , often flavored , cigarettes ) , and chewing tobacco and future intentions to smoke or use chewing tobacco . RESULTS Findings showed that students in the intervention group were significantly less likely than were students in the control group to exhibit increases in cigarette smoking or bidi smoking over the 2-year study period . They were also less likely to intend to smoke or chew tobacco in the future . CONCLUSIONS School-based programs similar to the intervention examined here should be considered as part of a multi strategy approach to reducing tobacco use among young people in India BACKGROUND This paper examines the effectiveness of the " Smokefree Class Competition " with regard to primary and secondary prevention of  smoking in adolescents .  Each participating class has to decide if they want to be a " Smokefree Class " for the six-month period from fall to spring . Classes monitor their (non-)smoking behaviour and report it to the teacher regularly . Classes in which pupils refrain from smoking for this period of time participate in a prize draw , where they can win a number of attractive prizes . METHODS A control group study with repeated measurements was carried out in order to evaluate the effectiveness of the competition . The sample consisted of 131 participating and non-participating classes ( N of the pupils = 2,142 ; mean age 12.9 years , SD = 0.98 ) .  Smoking status was assessed on two occasions : ( a ) prior to the beginning of the competition , and ( b ) 6 month after the end of the competition . RESULTS With regard to the smoking status at baseline no differences could be found between the experimental and the control group ( 15.2 % vs. 18.5 % smoking pupils ) . In the follow-up measurement , pupils in the control group showed significantly higher prevalences of smoking than the experimental group in the post-measurement period ( 32.9 % vs. 25.5 % smoking pupils ) . More pupils in the experimental group stayed smokefree compared to the control group . No differential effects on smoking cessation could be found . CONCLUSIONS The results show that participation in the competition could delay the onset of smoking in adolescents ( primary prevention ) . The competition is not effective in smoking cessation in youth OBJECTIVES Previous research has suggested that early smoking initiation predicts longer duration of smoking , heavier daily consumption , and increased chances of nicotine dependence . This report set out to estimate the relationship between smoking cessation and age of initiation , as well as nicotine dependence , sex , race , and education . METHODS A sample of 1007 young adults was r and omly 
    Output:
    
There is little robust evidence to suggest that unintended consequences ( such as youth making false cl aims about their smoking status and bullying of smoking students ) are consistently associated with such interventions , although this has not been the focus of much research .