***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 The relative effectiveness of continued , lapsed , and delayed smoking prevention intervention was tested with senior high school students . The original intervention was conducted during Grade s 7 through 9 , with significantly fewer intervention students reporting smoking than control students . The intervention was reintroduced in the 11th grade to one-half of intervention students ( continued intervention ) , was withdrawn from the other half ( lapsed intervention ) , and was initiated with one-half control students ( delayed intervention ) . The 11th- grade smoking rates of these groups were compared to those of a fourth group , a continued control group . Results showed that continued control students reported significantly less smoking than continued control students and lapsed intervention students . Additionally , the delayed intervention group exhibited smoking rates lower than the lapsed intervention and continued control groups . This finding underscores the importance of continuing smoking prevention activities , as well as initiating these activities , in senior high school years OBJECTIVES This paper presents the 1-year outcomes evaluation of Project Towards No Drug Abuse ( Project TND ) , a large-scale indicated drug abuse prevention program in southern California applied to continuation high school youth , who are at high risk for drug abuse . METHODS The efficacy of nine-lesson health motivation -- social skills -- decision-making curriculum was evaluated in a three-condition experimental design . Twenty-one schools were r and omly assigned by block to one of three conditions -- st and ard care ( control ) , classroom program , and classroom program plus a semester-long school-as-community component . A pretest was followed by a 3-week-long drug abuse prevention program and then a posttest at 14 continuation high schools . The 7 st and ard care schools received only the pretest followed by the posttest ( same time duration ) . Subjects were followed up 1 year later . RESULTS Changes in use of cigarettes , alcohol , marijuana , and hard drugs were assessed in a pretest-1-year follow-up time interval . The follow-up rate was 67 % ( analysis n = 1,074 ) . Indicated preventive effects were found on alcohol and hard drug use . No differences were found across the two program conditions . CONCLUSIONS Project TND is the first program to demonstrate 1-year self-reported behavioral effects on alcohol use and hard drug use among older , high-risk youth by using a school-based , limited-session model OBJECTIVES The purpose of this study was to implement and evaluate the effectiveness of a long-term tobacco use prevention program for junior high school students that used college undergraduate change agents  and telephone boosters . METHODS A psychosocial intervention combining refusal skills training , contingency management , and other tobacco use prevention method ologies such as telephone and mail boosters was implemented in 11 junior high schools in San Diego County , California . Eleven other junior high schools served as controls . Of the 2668 participants , 57 % were White/non-Hispanic , 24 % were Hispanic , and 19 % were of other racial/ethnic groups . College undergraduates served as change agents for both the classroom and booster interventions , the latter of which was delivered in the third ( ninth- grade ) year of the program . RESULTS At the end of the third year , the prevalence of tobacco use within the past month was 14.2 % among the intervention students and 22.5 % among the controls , yielding an odds ratio of 0.71 for analysis at the school level . CONCLUSIONS Both college undergraduate change agents and direct one-to-one telephone interventions appear to provide cost-effective tobacco-related behavior modification This study investigated both substantive and method ological issues associated with school-based smoking prevention programs . Substantive issues included the efficacy of a refusal skills training curriculum and of parent messages mailed to students ' homes . Method ological issues included the effects of assigning classrooms versus entire schools to experimental conditions and determination of the effects of attrition on internal and external validity . Results revealed differential impact for different subgroups of adolescents . The refusal skills program produced lower rates of smoking than the control condition for students who were smokers at the pretreatment assessment but may have produced detrimental effects among males who were nonsmokers at pretest . The provision of parent messages did not affect outcome . Method of assignment ( schools versus classrooms ) failed to produce significant effects , and attrition did not affect internal validity . However , the above differential findings , as well as the impact of attrition on external validity , raise questions concerning the generalizability of smoking prevention programs 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 This study described the development of  tobacco smoking  of subjects between ages 12 and 36 using prospect ively collected self-reports of 212 Swedish men and women born in the 1950s .  Smoking habits were studied in terms of stability , longitudinal patterns of smoking , and the relation between age of initiation and later smoking . Findings showed that  light smoking  ( up to 6 cigarettes/day ) did not remain stable after adolescence . Typical development patterns from age 15 to age 36 included staying a nonsmoker ; smoking intensely ( > 10 cigarettes/day ) and continuing into adulthood ; smoking less intensely for some periods ; or smoking intensely and quitting before age 36 . Differences in age at smoking initiation were related to later habitual smoking only when participants reported initiation had occurred after age 12 This study evaluated the substance initiation effects of an intervention combining family and school-based competency-training intervention components . Thirty-six rural schools were r and omly assigned to 1 of 3 conditions : ( a ) the classroom-based Life Skills Training ( LST ) and the Strengthening Families Program : For Parents and Children 10 - 14  , ( b ) LST only , or ( c ) a control condition . Outcomes were examined 1 year after the intervention posttest , using a substance initiation index ( SII ) measuring lifetime use of alcohol , cigarettes , and marijuana and by rates of each individual substance . Planned intervention-control contrasts showed significant effects for both the combined and LST-only interventions on the SII and on marijuana initiation . Relative reduction rates for alcohol initiation were 30.0 % for the combined intervention and 4.1 % for LST only OBJECTIVES We present 1-year follow-up data from a school-based tobacco use prevention project design ed to test the effectiveness of three main components of social influence programs . The components teach refusal skills , awareness of social misperceptions about tobacco use , and misconceptions about physical consequences . METHODS Four different curricula were developed and tested in a r and omized experiment involving 48 junior high schools . The outcome variables examined were changes in initial and weekly cigarette and smokeless tobacco use 1 year after the intervention . RESULTS Analyses indicated that each of the component programs were effective in decreasing both the initial and the weekly use of cigarettes except for the curriculum in which refusal skills were taught . Also , each curriculum was effective in decreasing the initial use of smokeless tobacco except for the one aim ed at correcting social misperceptions . Only the combined curriculum showed an effect on the weekly use of smokeless tobacco . CONCLUSIONS The combined intervention was the most effective overall in reducing the initial and weekly use of cigarettes and smokeless tobacco . This suggests that different reasons for use exist and need to be counteracted simultaneously . However , since single programs were also effective in reducing all but weekly smokeless tobacco use , any of these components may be worthwhile prevention tools OBJECTIVE We examined the generalizability of a successful classroom-based prevention program developed for youth at alternative high schools ( high risk ) to youth at general high schools . METHOD A replication of a previously tested prevention program in a general high school population was conducted with 1-year follow-up data . Classrooms within each of three schools were r and omly assigned to two conditions , classroom education or st and ard care control . RESULTS Statistically significant effects on alcohol and illicit drug use were achieved in this population through a 1-year period following the program , although effects were not achieved on cigarette smoking and marijuana use . CONCLUSIONS These results suggest that this program ( Project Towards No Drug Abuse ) has applicability to a wide range of older teens BACKGROUND This article reports the results of a 5-year , longitudinal evaluation of the effectiveness of Drug Abuse Resistance Education ( DARE ) , a school-based primary drug prevention curriculum design ed for introduction during the last year of elementary education . DARE is the most widely disseminated school-based prevention curriculum in the United States . METHOD Twenty-three elementary schools were r and omly assigned to receive DARE and 8 were design ated comparison schools . Students in the DARE schools received 16 weeks of protocol -driven instruction and students in the comparison schools  received a drug education unit as part of the health curriculum . All students were pretested during the 6th grade prior to delivery of the programs , posttested shortly after completion , and resurveyed each subsequent year through the 10th grade . Three-stage mixed effects regression models were used to analyze these data . RESULTS No significant differences were observed between intervention and comparison schools with respect to cigarette , alcohol , or marijuana use during the 7th grade , approximately 1 year after completion of the program , or over the full 5-year measurement interval . Significant intervention effects in the hypothesized direction were observed during the 7th grade for measures of students ' general and specific attitudes toward drugs , the capability to resist peer pressure , and estimated level of drug use by peers . Over the full measurement interval , however , average trajectories of change for these outcomes were similar in the intervention and comparison conditions . CONCLUSIONS The findings of this 5-year prospect i ve study are largely consonant with the results obtained from prior short-term evaluations of the DARE curriculum , which have reported limited effects of the program upon drug use , greater efficacy with respect to attitudes , social skills , and knowledge , but a general tendency for curriculum effects to decay over time . The results of this study underscore the need for more robust prevention programming targeted specifically at risk factors , the inclusion of booster sessions to sustain positive effects , and greater attention to interrelationships between developmental processes in adolescent substance use , individual level characteristics , and social context OBJECTIVE To evaluate the long-term efficacy of 
    Output:
    
Few studies have evaluated the long-term impact of school-based smoking prevention programs rigorously .
Among the 8 programs that have follow-up data to age 18 or 12th grade , we found little to no evidence of long-term effectiveness