***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: BACKGROUND No long-term impact has yet been observed with the use of the social-influences approach to school-based smoking prevention for youth . However , whether this lack of impact is due to method ologic problems with the studies or to the failure of the interventions is unclear . The Hutchinson Smoking Prevention Project ( HSPP ) , conducted from September 1984 through August 1999 , aim ed to attain the most rigorous r and omized trial possible to determine the long-term impact of a theory-based , social-influences , grade 3 - 12 intervention  on smoking prevalence among youth . METHODS Forty Washington school districts were r and omly assigned to the intervention or to the  control condition .  Study participants were children enrolled in two consecutive 3rd grade s in the 40 districts ( n = 8388 ) ; they were followed to 2 years after high school . The trial achieved high implementation fidelity and 94 % follow-up . Data were analyzed with the use of group-permutation methods , and all statistical tests were two-sided . RESULTS No significant difference in prevalence of daily smoking was found between students in the control and experimental districts , either at grade 12 ( difference [ Delta ] = 0.2 % , 95 % confidence interval [ CI ] = -4.6 % to 4.4 % , and P = .91 for girls ; Delta = 0.3 % , 95 % CI = -5.0 % to 5.5 % , and P = .89 for boys ) or at 2 years after high school ( Delta = -1.4 % , 95 % CI = -5.0 % to 1.6 % , and P = .38 for girls ; Delta = 2.6 % , 95 % CI = -2.5 % to 7.7 % , and P = .30 for boys ) . Moreover , no intervention impact was observed for other smoking outcomes , such as extent of current smoking or cumulative amount smoked , or in subgroups that differ in a priori specified variables , such as family risk for smoking . CONCLUSION The rigor of the HSPP trial suggests high credence for the intervention impact results . Consistent with previous trials , there is no evidence from this trial that a school-based social-influences approach is effective in the long-term deterrence of smoking among youth Our objective was to verify the effectiveness of a program based on the Life Skills Training approach with a greater extent than usual , not applied by teachers and a very high degree of reliability regarding the implementation of the expected content . Twenty-eight secondary schools in Granada ( Spain ) were r and omly assigned to the intervention or control group . The students in the intervention group received 21 one-hour sessions in the first year and 12 one-hour sessions in the second year , whereas those in the control group received no health education or preventive sessions . Students completed question naires before and after the first year of sessions , before and after the second year , and at 1 year after the program . All five question naires were completed by 77 % of the 1048 students initially enrolled in the study . The results suggest that the program had no preventive effects either immediately or at 1 year after its application . Application of the Life Skills Training approach does not appear to prevent the onset of smoking but may prove effective for avoiding escalation of the consumption levels of tobacco or other problematic drugs Background Smoking rates are projected to increase substantially in developing countries such as South Africa . Purpose The aim of this study was to test the efficacy of two contrasting approaches to school-based smoking prevention in South African youth compared to the st and ard health education program . One experimental program was based on a skills training/peer resistance model and the other on a harm minimization model . Method Thirty-six public schools from two South African provinces , KwaZulu-Natal and the Western Cape , were stratified by socioeconomic status and r and omized to one of three groups . Group 1 ( comparison ) schools ( n = 12 ) received usual tobacco use education . Group 2 schools ( n = 12 ) received a harm minimization curriculum in grade s 8 and 9 . Group 3 schools ( n = 12 ) received a life skills training curriculum in grade s 8 and 9 . The primary outcome was past month use of cigarettes based on a self-reported question naire . Result Five thous and two hundred sixty-six students completed the baseline survey . Of these , 4,684 ( 89 % ) completed at least one follow-up assessment . The net change in 30-day smoking from baseline to 2-year follow-up in the control group was 6 % compared to 3 % in both harm minimization ( HM ) and life skills training ( LST ) schools . These differences were not statistically significant . Intervention response was significantly moderated by both gender and race . The HM intervention was more effective for males , whereas the life skills intervention was more effective for females . For black African students , the strongest effect was evident for the HM intervention , whereas the strongest intervention effect for “ colored ” students was evident for the LST group . Conclusion The two experimental curricula both produced similar overall reductions in smoking prevalence that were not significantly different from each other or the control group . However , the impact differed by gender and race , suggesting a need to tailor tobacco and drug use prevention programs . More intensive intervention , in the classroom and beyond , may be needed to further impact smoking behavior Tobacco and drug use remain major public health concerns . The aim of this study was to evaluate the effectiveness of a school health intervention program using life skills training ( LST ) to reduce tobacco and drug use among Thai high school students . A r and omized pretest and post-test comparative design was used to evaluate the effectiveness of the LST program . A total of 170 Thai students in grade s 7 - 12 were r and omly selected . The students in the control group received the tobacco and drug education curriculum normally provided ; the intervention group received a LST program that provided information and skills specifically related to drug and tobacco use . Students in the school health intervention program had statistically significant positive effects regarding knowledge level , attitudes , and the development of refusal , decision-making , and problem-solving skills . The results showed that a LST program was effective for preventing tobacco and drug use in Thai high school students This paper evaluates a smoking prevention intervention aim ed at vocational school students , consisting of an existing Dutch in-school program ( three lessons each lasting 50 min ) and a computer-based tailored out-of-school program ( three tailored letters with smoking prevention messages mailed to students ' homes ) . Nineteen schools that already participated in the in-school program were r and omly assigned to the in-school or to the combined in-school and out-of-school condition . The remaining 17 schools were r and omly assigned to the out-of-school condition or to the control group . Effect outcomes were assessed at 6 , 12 and 18 months after a pre-test , and were based on initiation among never-smokers and continuation among ever-smokers . Twelve months after the pre-test ( post-test 2 ) , the in-school intervention was successful in preventing  vocational school students from continuing to smoke , compared with students in the control condition [ odds ratio ( OR ) = 0.49 ; 95 % confidence interval ( CI ) = 0.29 - 0.84 ] . Eighteen months after the pre-test ( post-test 3 ) , the tailored out-of-school intervention was successful in preventing smoking initiation , compared with students in the control condition ( OR = 0.42 ; 95 % CI = 0.18 - 0.96 ) . The effect of the combined approach was not larger than the sum of the effects of the in-school and the out-of-school effects This study used Complier Average Causal Effect analysis ( CACE ; see G. Imbens & D. Rubin , 1997 ) to examine the impact of an adaptive approach to family intervention in the public schools on rates of substance use and antisocial behavior among students ages 11 - 17 . Students were r and omly assigned to a family-centered intervention ( N = 998 ) in 6th grade and offered a multilevel intervention that included ( a ) a universal classroom-based intervention , ( b ) the Family Check-Up ( selected ; T. J. Dishion & K. Kavanagh , 2003 ) , and ( c ) family management treatment ( indicated ) . All services were voluntary , and approximately 25 % of the families engaged in the selected and indicated levels . Participation in the Family Check-Up was predicted by 6th- grade teacher ratings of risk , youth reports of family conflict , and the absence of biological fathers from the youths ' primary home . Relative to r and omized matched controls , adolescents whose parents engaged in the Family Check-Up exhibited less growth in alcohol , tobacco , and marijuana use and problem behavior during ages 11 through 17 , along with decreased risk for substance use diagnoses and police records of arrests by age 18 BACKGROUND The prevalence of adolescent smoking has been increasing rapidly in China .  Theory-based smoking prevention programmes in schools may be an effective approach in preventing smoking among Chinese adolescents . METHODS A school-level cluster r and omized controlled trial was conducted among 7th and 8th grade students ( N = 2343 ) in four junior high schools in southern China during 2004 - 06 .  The theory-based , multi-level intervention was compared with the st and ard health curriculum . Outcome measures comprised changes in students ' smoking-related knowledge , attitudes and behaviour . RESULTS The mean knowledge scores from baseline to the 1- and 2-year follow-ups increased more in the intervention group than in the control group , whereas there was little change in attitude scores . At the 1-year follow-up ( the total sample ) , the interventions reduced the probability of baseline experimental smokers ' escalating to regular smoker [ 7.9 vs 18.3 % ; adjusted odds ratio ( OR ) 0.34 , 95 % confidence interval ( CI ) 0.12 - 0.97 , P = 0.043 ] , but did not reduce the probability of baseline non-smokers ' initiating smoking ( 7.9 vs 10.6 % ; adjusted OR 0.86 , 95 % CI 0.54 - 1.38 , P = 0.538 ) . At the 2-year follow-up ( only 7th grade students ) , similar proportions of baseline non-smokers initiated smoking in the intervention group and the control group ( 13.5 vs 13.1 % ) , while a possibly lower proportion of baseline experimental smokers escalated to regular smoking in the intervention group than the control group ( 22.6 vs 40.0 % ; adjusted OR 0.43 , 95 % CI 0.12 - 1.57 , P = 0.199 ) . CONCLUSIONS This multi-level intervention programme had a moderate effect on inhibiting the escalation from experimental to regular smoking  among Chinese adolescents , but had little effect on the initiation of smoking . The programme improved adolescents ' smoking-related knowledge , but did not change their attitudes towards smoking This study tested the hypothesis that cigarette smoking adoption among adolescents could be suppressed by providing school-based videotape instruction for resisting social influences to smoke . The utilization of same-age peer leaders was also varied to test whether their participation in the classroom would enhance program effects . Seventh grade students ( N = 540 ) from one junior high school in Southern California were r and omly assigned by classrooms ( N = 15 ) to : ( a ) videotape instruction , ( b ) videotape instruction plus peer leader involvement , or ( c ) survey-only .  Seventh grade students ( N = 234 ) in a second junior high school served as a measurement-only control . Assessment s were conducted at the beginning and end of the academic year . Results revealed a marked suppression in the onset of both experimental and regular smoking among those students exposed to the pressure resistance training with peer leader involvement . Pressure resistance training without peer leader involvement produced a more variable and less powerful effect on students ' smoking behavior . Data collected on students ' use of alcohol and marijuana revealed a generalized suppression effect , albeit weaker than for tobacco , among those students exposed to the social resistance training with peer leader involvement . Results provide further encouraging support for the use of peer-led pressure resistance training in preventing adolescent drug use In this article , we examine the impact of two universal , grade 1 preventive interventions on the onset of tobacco smoking as assessed in early adolescence . The classroom-centered ( CC ) intervention was design ed to reduce the risk for tobacco smoking by enhancing teachers ' behavior management skills in first grade and , thereby , reducing child attention problems and aggressive and shy behavior-known risk behaviors for later substance use . The family-school partnership ( FSP ) intervention targeted these early risk behaviors via improvements in parent-teacher communication and parents ' child behavior management strategies . A cohort of 678 urban , predominately African-American , public school students were r and omly assigned to one of three Grade 1 classrooms at entrance to primary school ( age 6 ) . One classroom featured the CC intervention , a second the FSP intervention , and the third served as a control classroom . Six years later , 81 % of the students completed audio computer-assisted self-interviews . Relative to controls , a modest attenuation in the risk of smoking initiation was found for students who had been assigned to either the CC or FSP intervention classrooms ( 26 % versus 33 % ) ( adjusted relative risk for CC/control contrast=0.57 , 95 % confidence interval ( CI ) , 0.34 - 0.96 ; adjusted relative risk for FSP/control contrast=0.69 , 95 % CI , 0.50 - 0.97 ) . Results lend support to targeting the early antecedent risk behaviors for tobacco smoking OBJECTIVE To examine the effectiveness of a drug abuse prevention program in reducing the initiation and escalation of smoking in a sample of predominantly minority junior high school girls . METHODS The 15-session prevention program teaches 
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Principal findings were not sensitive to inclusion of booster sessions in curricula or to whether they were peer-led or adult-led .
Differentiation into tobacco-only or multifocal curricula had a similar effect on the primary findings .
Few trials assessed outcomes by gender : there were significant effects for females at both follow-up periods , but not for males .
RCTs of baseline never-smokers at longest follow-up found an overall significant effect with average 12 % reduction in starting smoking compared with controls , but no effect for all trials pooled at ≤1 year .
However , combined social competence/social influences curricula showed a significant effect at both follow-up periods .