***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 BACKGROUND Interventions design ed to prevent tobacco and alcohol use targeting high-risk adolescents are limited . In addition , few studies have attempted to improve parent-child communication skills as a way of improving and maintaining healthy youth decision-making . METHODS A total of 660 Hispanic migrant families participated in a r and omized pre-post control group study that was utilized to determine the impact of the intervention on parent-child communication . Both treatment and attention-control groups of youth were exposed to an eight-session culturally sensitive program presented by bilingual/bicultural college students . Parents jointly attended three of the eight sessions and participated in helping their child complete homework assignments supporting the content of each session . The content of the treatment intervention included ( 1 ) information about tobacco and alcohol effects , ( 2 ) social skills training ( i.e. , refusal skills ) , and ( 3 ) the specific development of parent-child communication skills to support healthy youth decisions . RESULTS Significant intervention by household size interactions for both parent and youth perceptions of communication were found indicating that the treatment was effective in increasing communication in families with fewer children . Based on the effect size and the previously established relationship between communication and susceptibility to tobacco and alcohol use , it was determined that the intervention effect could be translated into a future 5 to 10 % decrease in susceptibility for these smaller families . CONCLUSIONS A culturally sensitive family-based intervention for migrant Hispanic youth was found to be effective in increasing perceived parent-child communication in families with fewer children . It is expected that increases in this important protective factor will lead to later observed decreases in tobacco and alcohol use Background Although waterpipe tobacco smoking seems to be increasing on U.S. university campuses , these data have come from convenience sample s. Purpose We aim ed to determine the prevalence of and associations with waterpipe tobacco smoking among a r and om sample of students . Methods We surveyed a r and om sample of graduate and undergraduate students at a large , urban university . We used multivariate modeling to determine independent associations between belief-related predictors and waterpipe tobacco smoking . Results Of the 647 respondents ,  waterpipe smoking was reported in 40.5 % , over the past year in 30.6 % , and over the past 30 days in 9.5 % . Over half of the sample ( 52.1 % ) perceived that tobacco smoking from a waterpipe was less addictive than cigarette smoking . In fully adjusted multivariate models , 1-year waterpipe smoking was associated with low perceived harm ( OR = 2.54 , 95 % CI = 1.68 , 3.83 ) , low perceived addictiveness ( OR = 4.64 , 95 % CI = 3.03 , 7.10 ) , perception of high social acceptability ( OR = 20.00 , 95 % CI = 6.03 , 66.30 ) , and high perception of popularity ( OR = 4.72 , 95 % CI = 2.85 , 7.82 ) . Conclusions In this sample , lifetime waterpipe use was as common as lifetime cigarette use . Perception of harm , perception of addictiveness , social acceptability , and popularity were all strongly related to waterpipe smoking Sc and inavian moist snuff ( snus )  is cl aim ed to be a safer alternative to smoking . We aim ed to quantify cancer incidence among male snus users and to shed light on the net health outcome by study ing their overall mortality . A cohort , comprised of 9,976 men who participated in a population -based survey , was compiled in 1973 - 74 . Follow-up until January 31 , 2002 , was accomplished through record-linkages with nation-wide and essentially complete registers of demographics , cancer and causes of deaths . Adjusted relative risks among exposed relative to unexposed men were estimated using Cox proportional hazards regression . The cohort members contributed more than 220,000 person-years at risk for cancer . A statistically significant increase in the incidence of the combined category of oral and pharyngeal cancer among daily users of snus ( incidence rate ratio 3.1 , 95 % confidence interval 1.5 - 6.6 ) was found . Overall mortality was also slightly increased ( hazard ratio 1.10 , 95 % confidence interval 1.01 - 1.21 ) . Although the combined previous literature on snus and oral cancer weigh toward no association , this population -based prospect i ve study provided suggestive evidence of snus-related risks that can not be lightly ignored OBJECTIVES This study investigated the efficacy of a social-influences tobacco prevention program conducted with adolescents living in a high tobacco production area . METHODS Students in 10 experimental schools completed the tobacco prevention program and a booster intervention .  Control students received health education as usual . RESULTS After 2 years of treatment , smoking rates in the treatment group ( vs the control group ) were lower for 30-day , 7-day , and 24-hour smoking . The intervention had more of an impact on those who were involved in raising tobacco than it did on those not involved in raising tobacco . CONCLUSIONS Although modest , effects were achieved with minimal intervention time in a high-risk group , indicating that social-influences prevention programs may be effective in such groups BACKGROUND This article discusses the development , implementation , and preliminary testing of an intervention to reduce cancer risks through tobacco use prevention and dietary modification among Native American youth in the Northeastern United States . METHODS The intervention outcome study includes a research design and outcome measurement instruments . In collaboration with Native American communities , reservations , and organizations in the Northeastern United States , implementation of the design quantifies the separate and combined effects of a tobacco use prevention and a dietary modification intervention . RESULTS Native American youths in the tobacco prevention intervention and in the combined tobacco and dietary intervention increased their knowledge of tobacco facts and their awareness of the motives of tobacco advertising , and showed higher ratings for an ability to resist peer pressure and to refuse offers of tobacco use between pretest and posttest . Youths in the combined intervention were significantly less apt to report smoking of any kind . Youths in the tobacco use prevention-only condition reported significantly less smoking than their counterparts in the dietary modification-only condition and control condition on 4 of 8 measurement items . As for dietary variables , pretest to posttest measurement scores showed that , after receiving the curriculum , youths in the dietary modification intervention and in the combined intervention improved their knowledge of the health implication s of consuming dietary fat , fiber , fruits , and vegetables . Youths in the dietary modification and combined intervention also improved their scores of knowledge related to cancer risk-reducing nutritional practice s , cultural dietary habits , and healthy food choices available for Native American cultures . Youths in the dietary modification-only condition report significantly increasing their consumption of complex carbohydrates and significantly decreasing their fat intake between pretest and posttest occasions . CONCLUSIONS Data from this longitudinal study suggest the value of the FACETS curriculum for helping Native American youth reduce their risks for cancer associated with tobacco use and dietary preference and consumption patterns . In particular , results indicate the enhanced effects of the combined tobacco use prevention and dietary modification intervention for preventing tobacco use and for improving youths ' knowledge and attitudes with regard to tobacco use and diet . Further , the study demonstrates the value of collaborating with Native American organizations to design a cancer risk-reducing curriculum and to implement tests of that curriculum 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 selected from a large health maintenance organization in southeast Michigan .  Hazard ratios of quitting associated with age at smoking initiation were estimated among 414 persons who smoked daily for 1 month or more . RESULTS With potential confounders controlled for , the likelihood of cessation was significantly higher in smokers who initiated smoking after age 13 . The hazard ratio for quitting associated with smoking initiation at ages 14 to 16 was 1.6 and with initiation at or after age 17 was 2.0 , compared with initiation at or before 13 years of age . Factors that decreased the likelihood of cessation were nicotine dependence and low education . CONCLUSIONS Public policy to discourage early smoking , if it succeeds in delaying the initiation of smoking , might contribute to the reduction of smoking-related mortality and morbidity by increasing the potential for quitting BACKGROUND This paper examines whether the Massachusetts Tobacco Control Program is affecting the rates of smoking and smokeless tobacco use among Massachusetts ' youth . METHODS School survey data from the Massachusetts Prevalence Study were analyzed to estimate differences between 1993 and 1996 rates of youth cigarette and smokeless tobacco use , attitudes toward smoking , and awareness of cigarette ads and promotions of antismoking messages . RESULTS Lifetime and Current Smoking rates declined significantly among middle school males , contrasting with stable national trends . Among girls in this age group , Lifetime and Current Smoking did not change significantly . Hispanic middle school students exhibited a significant decline in Lifetime Use . There were no significant changes in Lifetime or Current Smoking rates among high school students .  Lifetime use of smokeless tobacco declined among middle school students while Current Use declined among both middle and high school students . Students reported declines in awareness of cigarette ads or promotions and increases in awareness of antismoking messages . CONCLUSIONS These results provide evidence for cautious optimism regarding the impact of tobacco control , but indicate that these efforts should begin earlier and that additional research is needed to underst and and address the problems of tobacco use by girls This paper describes the curricula contents , and presents data to evaluate the implementation , process and immediate post-test knowledge of Project Towards No Tobacco Use ( Project TNT ) . Four different school-based tobacco use prevention curricula were developed to counteract the effects of three types of tobacco use acquisition variables typically addressed within a comprehensive social influences program : ( 1 ) peer approval for using tobacco ( normative social influence ) , ( 2 ) incorrect social informational provided about tobacco use ( information social influence ) and ( 3 ) lack of knowledge or misperceptions about physical consequences result ing from tobacco use . Three curricula were design ed to counteract the effects of single acquisition variables , whereas a fourth curriculum was design ed to counteract the effects of combined social and physical consequences-related influences . These curricula were delivered to seventh grade students by trained project health educators to maximize implementation . ' Program ' schools , those schools that received one of these curricula , were compared to ' control ' schools that provided a systematic health education delivered by school personnel . A total of five conditions were contrasted through use of a r and omized experiment involving 48 southern California junior high schools . This paper documents high levels of implementation in all program conditions . Also , favorable process ratings were obtained across the four program conditions , using multiple measures and sources of ratings ( students , health educators and classroom teachers who observed curricula delivery ) . Finally , knowledge item sets completed by the students demonstrated discriminant validity across all five conditions . Because the program conditions were discriminable , yet were quite similar in implementation and process ratings , planned future study of behavioral outcomes can be interpreted as relatively uncontaminated by delivery or credibility confounds 
    Output:
    
CONCLUSIONS New school-based programs are needed to address current issues in tobacco control .