***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 Statistical mediation analysis can be used to improve the design of obesity prevention and treatment programs by identifying the possible mechanisms through which an intervention achieved its effects . The aim of this study was to identify mediators of weight loss in an Internet-based weight-loss program specifically design ed for overweight men . Methods The Self-Help , Exercise and Diet using Information Technology ( SHED-IT ) program was a 3-month r and omized controlled trial ( Internet-based intervention group vs information only control group ) that was implemented in 2007 with baseline and 6-month follow-up assessment of weight , physical activity and dietary behaviors . Intention-to-treat and per- protocol mediation analyses were conducted using a product-of-coefficients test . Results Participants ( N = 65 ) were overweight and obese male academic ( n = 10 ) and non-academic ( n = 27 ) staff and students ( n = 28 ) from the University of Newcastle , Australia . Mean ( SD ) age = 35.9 ( 11.1 ) years and mean ( SD ) BMI = 30.6 ( 2.8 ) . In the intention-to-treat analysis , both groups lost weight , but relative to the control group , the intervention did not have a statistically significant ' total effect ' on weight , τ = -.507 , p = .716 ( 95 % CI = -3.277 to 2.263 ) . In the per- protocol analysis , the intervention had a statistically significant ' total effect ' on weight , τ = -4.487 , p < .05 ( 95 % CI = -8.208 to -.765 ) . The intervention did not have a statistically significant effect on any of the hypothesized mediators and none of the behavioral variables mediated weight loss in the SHED-IT program . Although participants in the intervention group reduced their fat intake over the study period , the changes did not satisfy the criteria for mediation . Conclusion Few studies have examined the mediators of weight loss in obesity treatment interventions . While none of the hypothesized mediators satisfied the criteria for mediation in the current study , there was some evidence to suggest that overweight men in the SHED-IT intervention reduced their fat intake over the study period . Future obesity treatment and prevention programs should explore behavioral mediators of weight loss using appropriate statistical methods .Trial Registration Australian New Zeal and Clinical Trials Registry No : ANZCTRN12607000481471 PURPOSE To examine the feasibility and efficacy of a theory-driven and family-based program delivered online to promote healthy lifestyles and weights in Chinese American adolescents . METHODS A r and omized controlled study of a web-based intervention was developed and conducted in 54 Chinese American adolescents ( ages , 12 - 15 years ) and their families .  Data on anthropometry , blood pressure , dietary intake , physical activity , and knowledge and self-efficacy regarding physical activity and nutrition were collected at baseline and 2 , 6 , and 8 months after the baseline assessment . Data were analyzed using linear mixed modeling . RESULTS The intervention result ed in significant decreases in waist-to-hip ratio and diastolic blood pressure and increases in vegetable and fruit intake , level of physical activity , and knowledge about physical activity and nutrition . CONCLUSION This web-based behavior program for Chinese American adolescents and their families seems feasible and effective in the short-term . Long-term effects remain to be determined . This type of program can be adapted for other minority ethnic groups who are at high-risk for overweight and obesity and have limited access to programs that promote healthy lifestyles Evaluation of acceptability and preliminary efficacy of an Internet and short message service ( SMS ) intervention for promoting physical activity ( PA ) in Hong Kong Chinese school children . An 8-week quasi-experimental study non-r and omly assigned 78 school children ( mean age=12.8 years ) to ( a ) an intervention group that received a stage-matched , Internet PA program two times a week and tailored SMS messages daily ; or ( b ) a no-treatment control . Data were collected from September 2008 until June 2009 . Acceptability measures included exposure rate and participant 's satisfaction . Efficacy measures were changes in stage of motivational readiness ( SMR ) and self-reported PA level . Intervention participants demonstrated significant pre-post increments in SMR ( Z=-2.558 , p=0.011 ) and self-reported PA level [ F(1 , 76)=4.50 , p=0.04 ] . There was a non-significant trend between groups in both SMR ( p=0.24 ) and PA ( p=0.13 ) . Despite the similar ratings of satisfaction between Internet ( M=3.12±0.74 ) and SMS ( M=3.12±0.84 ) , participants displayed distinct patterns of exposure with 66 % exhibiting a weekly login rate of 0.5 times/person and an average of 3.75 minutes/visit/person . In contrast , 79 % of participants read an average of 1.3 SMS/person/week and 47 % voluntarily replied to ∼3.8 SMS/person . These findings demonstrate the acceptability and preliminary efficacy of an Internet-SMS-based intervention for promoting PA in Hong Kong school children . The divergent exposure rates between the Internet and SMS may be a unique pattern for adolescents in early SMR . Future research should be cognizant of the importance of SMR since it may influence utilization and /or adherence Background The World Wide Web is an effective method for delivering health behavior programs , yet major limitations remain ( eg , cost of development , time and re source requirements , limited interactivity ) . Social media , however , has the potential to deliver highly customizable and socially interactive behavioral interventions with fewer constraints . Thus , the evaluation of social media as a means to influence health behaviors is warranted . Objective The objective of this trial was to examine and demonstrate the feasibility of using an established social networking platform ( ie , Facebook ) to deliver an 8 week physical activity intervention to a sample of low-active adolescents ( N=21 ; estimated marginal mean age 13.48 years ) . Methods Participants were r and omized to either an experimental ( ie , Behavioral ) or attentional control ( ie , Informational ) condition . Both conditions received access to a restricted-access , study -specific Facebook group where the group ’s administrator made two daily wall posts containing youth-based physical activity information and re sources . Primary outcomes included physical activity as assessed by accelerometry and self-report . Interactions and main effects were examined , as well as mean differences in effect sizes . Results Analyses revealed significant improvements over time on subjectively reported weekly leisure-time physical activity ( F 1,18=8.426 , P=.009 , η2 = .319 ) . However , there was no interaction between time and condition ( F 1,18=0.002 , P=.968 , η2 = .000 ) . There were no significant time or interaction effects among the objective ly measured physical activity variables . Examination of effect sizes revealed moderate-to-large changes in physical activity outcomes . Conclusions Results provide initial support for the feasibility of delivery of a physical activity intervention to low-active adolescents via social media . Whether by employing behavioral interventions via social media can result in statistically meaningful changes in health-related behaviors and outcomes remains to be determined . Trial Registration Clinical Trials.gov NCT01870323 ; http:// clinical trials.gov/show/NCT01870323 ( Archived by WebCite at http://www.webcitation.org/6SUTmSeZZ ) PURPOSE To compare the effectiveness of two school-based internet obesity prevention programs  for diverse adolescents on  body mass index ( BMI ) , health behaviors , and self-efficacy , and to explore moderators of program efficacy . It was hypothesized that the addition of coping skills training to a health education and behavioral support program would further enhance health outcomes . METHODS A r and omized clinical trial with cluster r and omization by class and repeated measures with follow-up at 3 and 6 months was conducted ( n = 384 ) .  BMI was assessed by use of st and ard procedures . Sedentary behavior , physical activity , nutrition behavior , self-efficacy , and satisfaction were assessed with self-report measures . Data analysis consisted of mixed model analyses with autoregressive covariance structure for repeated data by use of intent-to-treat procedures . RESULTS The mean age of students was 15.31 years ( ±0.69 ) , with a mean BMI of 24.69 ( ±5.58 ) . The majority were girls ( 62 % ) and of diverse race/ethnicity ( 65 % non-white ) . There were no significant differences between groups on any outcomes and no change in BMI over time . There were significant improvements in health behaviors ( sedentary behavior , moderate and vigorous physical activity , healthy eating , fruit and vegetable intake , sugar beverages , and junk food intake ) and self-efficacy . Gender and lesson completion moderated select health outcomes . There was excellent participation and high satisfaction with the programs . CONCLUSIONS School-based internet obesity prevention programs are appealing to adolescents and improve health behaviors . The differential effect of coping skills training may require longer follow-up PURPOSE The present study investigates the effect of the Activ-O-Meter , an internet-based computer-tailored physical activity intervention in adolescents in six European centers involved in the HELENA study . METHODS Adolescents ( 12 - 17 years old ) from Vienna , Ghent , Heraklion , Dortmund , Athens , and Stockholm were r and omized into intervention and control schools . Participants in the intervention condition received the computer-tailored advice at baseline and after 1 month . Participants in the control condition received a generic st and ard advice . Effects were evaluated after 1 ( n = 675 ) and 3 months ( n = 494 ) using multi-level modeling . Physical activity levels were measured using the International Physical Activity Question naire for adolescents ( IPAQ-A ) . RESULTS After 1 month , the intervention group reported higher levels of moderate ( beta = -32.8 , 95 % CI ( confidence interval ) : -64.2 to -1.4 ) and vigorous ( beta = -28.0 , 95 % CI : -50.7 to -5.3 ) physical activity in leisure time , as well as higher levels of cycling for transport ( beta = -19.1 , 95 % CI : -34.4 to -7.6 ) compared to the control group . After 3 months , when the intervention group had received the tailored feedback twice , intervention effects were even stronger . Favorable changes in physical activity levels of all intensities and in different context s were found in the tailored group compared to the control group . Among adolescents not reaching the physical activity recommendations at baseline similar effects as in the total sample were found . CONCLUSIONS The data indicated that the computer-tailored physical activity intervention had positive effects on physical activity levels among the adolescents . However , the implementation of the computer-tailored intervention in the schools was not feasible in all countries OBJECTIVE To evaluate the feasibility and effectiveness of a pilot family-based newsletter intervention to increase  fruit and vegetable ( FV ) consumption among adolescents . DESIGN Family-based , two-group r and omised control trial with baseline , post-intervention and follow-up measures . The intervention group received two FV newsletter packs over a 1 month period by postal mail . Social cognitive and behavioural choice theories provide the theoretical framework for the design and development of intervention material s. Control families were provided with all intervention material s at the end of the study . Adolescent FV consumption was assessed by an FFQ . Adolescent-reported barriers to eating FV , FV habits and preferences were the secondary outcomes , along with parent FV consumption , and parents reported knowledge , encouragement , home availability and accessibility of FV . Repeated- measures ANOVA was used to detect differences in behavioural and psychosocial outcomes between groups , time and group-by-time . SETTING East Midl and s , UK . SUBJECTS Forty-nine parents and adolescents aged 12 - 14 years . RESULTS Process evaluation indicated high reach , dose acceptability and fidelity of the intervention . At post-intervention and 6 weeks later at follow-up , adolescents in the intervention group had significantly higher fruit : ( P < 0.01 ) and vegetable ( P < 0.05 ) consumption and higher preferences for vegetables ( P < 0.01 ) , compared with the control group . At post-intervention and follow-up , parents in the intervention group had significantly higher fruit ( P < 0.001 ) and vegetable ( P < 0.01 ) consumption and reported higher accessibility of fruit and vegetables ( P < 0.001 ) , compared with those in the control group . CONCLUSIONS Family-based , newsletter interventions promoting FV consumption to adolescents appear to be feasible and effective at increasing FV consumption OBJECTIVE Guided by theory , this study explored cross-sectional differences in factors influencing adolescent eating behaviour including gender and socio-economic status ( SES ) , and subsequently tested the longitudinal predictive power of the models . DESIGN / SETTING /SUBJECTS Data were collected by question naires in a longitudinal study of adolescents ( age 13 years at baseline ) and their parents from Hordal and County , Norway . Association of personal and environmental variables ( family , friends , school/society ) with the consumption of fruit and vegetables ( FV ) and selected sources of fat and of sugar were assessed at age 15 The final cross-sectional models were subsequently employed in groups stratified by gender/SES and to predict consumption at age 21 RESULTS The model explained more of the variation in the sugar score ( 21 % ) and the FV score ( 13.5 % ) than in the fat score ( 5 % ) . SES was associated with both the sugar and FV scores . The strongest associations with the sugar score and FV were for 
    Output:
    
Significant behavior change was often seen when interventions included education , goal setting , self-monitoring , and parental involvement .
None of the publications reported cost-effectiveness .
It is possible to effect significant health behavior change in adolescents through digital interventions that incorporate education , goal setting , self-monitoring , and parental involvement .