Experimental design and methods for school-based randomized trials. Experience from the Hutchinson Smoking Prevention Project (HSPP)

Facilitators and Barriers to Pediatric Clinical Trial Recruitment and Retention in Rural and Community Settings: A Scoping Review of the Literature

Children in rural settings are underrepresented in clinical trials, potentially contributing to rural health disparities. We performed a scoping review describing available literature on barriers and facilitators impacting participation in pediatric clinical trials in rural and community-based (non-clinical) settings. Articles identified via PubMed, CINAHL, Embase, and Web of Science were independently double-screened at title/abstract and full-text levels to identify articles meeting eligibility criteria. Included articles reported on recruitment or retention activities for U.S.-based pediatric clinical studies conducted in rural or community-based settings and were published in English through January 2021. Twenty-seven articles describing 31 studies met inclusion criteria. Most articles reported on at least one study conducted in an urban or suburban or unspecified community setting (n=23 articles; 85%); fewer (n=10; 37%) reported on studies that spanned urban and rural settings or were set in rural areas. More studies discussed recruitment facilitators (n=25 studies; 81%) and barriers (n=19; 61%) versus retention facilitators (n=15; 48%) and barriers (n=8; 26%). Descriptions of recruitment and retention barriers and facilitators were primarily experiential or subjective. Recruitment and retention facilitators were similar across settings and included: contacts/reminders, community engagement and relationship-building, consideration of participant logistics, and incentives. Inadequate staff and resources were commonly cited recruitment and retention barriers. Few studies have rigorously examined optimal ways to recruit and retain rural participants in pediatric clinical trials. To expand the evidence base, future studies examining recruitment and retention strategies should systematically assess and report rurality and objectively compare relative impact of different strategies.

Cash transfers and HIV/HSV-2 prevalence: A replication of a cluster randomized trial in Malawi

INTRODUCTION

In this paper we perform a replication analysis of "Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: a cluster randomised trial" by Sarah Baird and others published in "The Lancet" in 2012. The original study was a two-year cluster randomized intervention trial of never married girls aged 13-22 in Malawi. Enumeration areas were randomized to either an intervention involving cash transfer (conditional or unconditional of school enrollment) or control. The study included 1708 Malawian girls, who were enrolled at baseline and had biological testing for HIV and herpes simplex virus type 2 (HSV-2) at 18 months. The original findings showed that in the cohort of girls enrolled in school at baseline, the intervention had an effect on school enrollment, sexual outcomes, and HIV and HSV-2 prevalence. However, in the baseline school dropout cohort, the original study showed no intervention effect on HIV and HSV-2 prevalence.

METHODS

We performed a replication of the study to investigate the consistency and robustness of key results reported. A pre-specified replication plan was approved and published online. Cleaned data was obtained from the original authors. A pure replication was conducted by reading the methods section and reproducing the results and tables found in the original paper. Robustness of the results were examined with alternative analysis methods in a measurement and estimation analysis (MEA) approach. A theory of change analysis was performed testing a causal pathway, the effect of intervention on HIV awareness, and whether the intervention effect depended on the wealth of the individual.

RESULTS

The pure replication found that other than a few minor discrepancies, the original study was well replicated. However, the randomization and sampling weights could not be verified due to the lack of access to raw data and a detailed sample selection plan. Therefore, we are unable to determine how sampling influenced the results, which could be highly dependent on the sample. In MEA it was found that the intervention effect on HIV prevalence in the baseline schoolgirls cohort was somewhat sensitive to model choice, with a non-significant intervention effect for HIV depending on the statistical model used. The intervention effect on HSV-2 prevalence was more robust in terms of statistical significance, however, the odds ratios and confidence intervals differed from the original result by more than 10%. A theory of change analysis showed no effect of intervention on HIV awareness. In a causal pathway analysis, several variables were partial mediators, or potential mediators, indicating that the intervention could be working through its effect on school enrollment or selected sexual behaviors.

CONCLUSIONS

The effect of intervention on HIV prevalence in the baseline schoolgirls was sensitive to the model choice; however, HSV-2 prevalence results were confirmed. We recommend that the results from the original published analysis indicating the impact of cash transfers on HIV prevalence be treated with caution.

Rationale, design and conduct of a school-based anti-smoking intervention: the "PEPITES" cluster randomized trial

BACKGROUND

In France smoking initiation rates amongst 11 to 16 year-olds are worryingly high. Several studies show that early initiation to psycho-active substances is a strong predictor of tobacco addiction. Decreasing the age at which tobacco use starts represents a key challenge for reducing tobacco usage. Implementing an intervention trial using educational workshops based on the Theory of Planned Behavior (TPB) and covering the 4 years of secondary school could be effective.

METHODS

"PEPITES" is an interventional research, using a cluster randomized design. It will allow assessing the effectiveness of interventions both in reducing the tobacco initiation rate and the regular smoking rate of secondary school pupils. We will also evaluate the process of the implementation of the study and thus will help to the transferability of the intervention. A partnership convention was signed between the JDB Foundation and the National Education authority which designated 6 secondary state schools for the PEPITES trial. The 6 schools were randomly allocated to 3 groups of 2 clusters each: 1 control group, 2 different intervention groups with 2 workshops per year during 4 years; In one of this group the 2 last workshops will be dedicated to measure the loss of taste due to tobacco smoking. In each school, all pupils in year 1 with a signed parental authorization (744 pupils) have been included in the trial. The interventions targets one of the variables of the TPB and the reinforcement of psycho-social competencies. We estimated that we could detect a reduction of increase ≥5.5 and 8% respectively in the 2 principal outcomes (risk α of 5%, and β of 80%).

DISCUSSION

Carrying out a randomized prevention trial in the school environment raises specific problems which it seems useful to detail for other educational actors who would like to perform a similar study. This discussion concerns the acceptation and cooperation of the National Education partners, the risks of contamination, the information given to parents and pupils and their consent, and the representativeness of the schools involved.

TRIAL REGISTRATION

ISRCTN85812512 . Registered 15 May 2018 by BioMed Central. (retrospectively registered).

Strategies for enhancing the implementation of school-based policies or practices targeting risk factors for chronic disease

BACKGROUND

A number of school-based policies or practices have been found to be effective in improving child diet and physical activity, and preventing excessive weight gain, tobacco or harmful alcohol use. Schools, however, frequently fail to implement such evidence-based interventions.

OBJECTIVES

The primary aims of the review are to examine the effectiveness of strategies aiming to improve the implementation of school-based policies, programs or practices to address child diet, physical activity, obesity, tobacco or alcohol use.Secondary objectives of the review are to: Examine the effectiveness of implementation strategies on health behaviour (e.g. fruit and vegetable consumption) and anthropometric outcomes (e.g. BMI, weight); describe the impact of such strategies on the knowledge, skills or attitudes of school staff involved in implementing health-promoting policies, programs or practices; describe the cost or cost-effectiveness of such strategies; and describe any unintended adverse effects of strategies on schools, school staff or children.

SEARCH METHODS

All electronic databases were searched on 16 July 2017 for studies published up to 31 August 2016. We searched the following electronic databases: Cochrane Library including the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations; Embase Classic and Embase; PsycINFO; Education Resource Information Center (ERIC); Cumulative Index to Nursing and Allied Health Literature (CINAHL); Dissertations and Theses; and SCOPUS. We screened reference lists of all included trials for citations of other potentially relevant trials. We handsearched all publications between 2011 and 2016 in two specialty journals (Implementation Science and Journal of Translational Behavioral Medicine) and conducted searches of the WHO International Clinical Trials Registry Platform (ICTRP) (http://apps.who.int/trialsearch/) as well as the US National Institutes of Health registry (https://clinicaltrials.gov). We consulted with experts in the field to identify other relevant research.

SELECTION CRITERIA

'Implementation' was defined as the use of strategies to adopt and integrate evidence-based health interventions and to change practice patterns within specific settings. We included any trial (randomised or non-randomised) conducted at any scale, with a parallel control group that compared a strategy to implement policies or practices to address diet, physical activity, overweight or obesity, tobacco or alcohol use by school staff to 'no intervention', 'usual' practice or a different implementation strategy.

DATA COLLECTION AND ANALYSIS

Citation screening, data extraction and assessment of risk of bias was performed by review authors in pairs. Disagreements between review authors were resolved via consensus, or if required, by a third author. Considerable trial heterogeneity precluded meta-analysis. We narratively synthesised trial findings by describing the effect size of the primary outcome measure for policy or practice implementation (or the median of such measures where a single primary outcome was not stated).

MAIN RESULTS

We included 27 trials, 18 of which were conducted in the USA. Nineteen studies employed randomised controlled trial (RCT) designs. Fifteen trials tested strategies to implement healthy eating policies, practice or programs; six trials tested strategies targeting physical activity policies or practices; and three trials targeted tobacco policies or practices. Three trials targeted a combination of risk factors. None of the included trials sought to increase the implementation of interventions to delay initiation or reduce the consumption of alcohol. All trials examined multi-strategic implementation strategies and no two trials examined the same combinations of implementation strategies. The most common implementation strategies included educational materials, educational outreach and educational meetings. For all outcomes, the overall quality of evidence was very low and the risk of bias was high for the majority of trials for detection and performance bias.Among 13 trials reporting dichotomous implementation outcomes-the proportion of schools or school staff (e.g. classes) implementing a targeted policy or practice-the median unadjusted (improvement) effect sizes ranged from 8.5% to 66.6%. Of seven trials reporting the percentage of a practice, program or policy that had been implemented, the median unadjusted effect (improvement), relative to the control ranged from -8% to 43%. The effect, relative to control, reported in two trials assessing the impact of implementation strategies on the time per week teachers spent delivering targeted policies or practices ranged from 26.6 to 54.9 minutes per week. Among trials reporting other continuous implementation outcomes, findings were mixed. Four trials were conducted of strategies that sought to achieve implementation 'at scale', that is, across samples of at least 50 schools, of which improvements in implementation were reported in three trials.The impact of interventions on student health behaviour or weight status were mixed. Three of the eight trials with physical activity outcomes reported no significant improvements. Two trials reported reductions in tobacco use among intervention relative to control. Seven of nine trials reported no between-group differences on student overweight, obesity or adiposity. Positive improvements in child dietary intake were generally reported among trials reporting these outcomes. Three trials assessed the impact of implementation strategies on the attitudes of school staff and found mixed effects. Two trials specified in the study methods an assessment of potential unintended adverse effects, of which, they reported none. One trial reported implementation support did not significantly increase school revenue or expenses and another, conducted a formal economic evaluation, reporting the intervention to be cost-effective. Trial heterogeneity, and the lack of consistent terminology describing implementation strategies, were important limitations of the review.

AUTHORS' CONCLUSIONS

Given the very low quality of the available evidence, it is uncertain whether the strategies tested improve implementation of the targeted school-based policies or practices, student health behaviours, or the knowledge or attitudes of school staff. It is also uncertain if strategies to improve implementation are cost-effective or if they result in unintended adverse consequences. Further research is required to guide efforts to facilitate the translation of evidence into practice in this setting.

Systematic review of universal school-based 'resilience' interventions targeting adolescent tobacco, alcohol or illicit substance use: A meta-analysis

Universal school-based interventions that address adolescent 'resilience' may represent a means of reducing adolescent substance use, however previous systematic reviews have not examined the effectiveness of such an intervention approach. A systematic review was undertaken to 1) assess whether universal school-based 'resilience' interventions are effective in reducing the prevalence of tobacco, alcohol or illicit substance use by adolescents, and 2) describe such effectiveness per intervention characteristic subgroups. Eligible studies were peer-reviewed reports (1994-2015) of randomised controlled trials including participants aged 5-18years that reported adolescent tobacco, alcohol or illicit substance use, and implemented a universal school-based 'resilience' intervention (i.e. those addressing both individual (e.g. self-esteem) and environmental (e.g. school connectedness) protective factors of resilience). Trial effects for binary outcomes were synthesised via meta-analyses and effect sizes reported as odds ratios. Subgroup (by intervention type, prevention approach, setting, intervention duration, follow-up length) and sensitivity analyses (excluding studies at high risk of bias) were conducted. Nineteen eligible studies were identified from 16,619 records (tobacco: n=15, alcohol: n=17, illicit: n=11). An overall intervention effect was found for binary measures of illicit substance use (n=10; OR: 0.78, 95%CI: 0.6-0.93, p=0.007,Tau²=0.0, I²=0%), but not tobacco or alcohol use. A similar result was found when studies assessed as high risk of bias were excluded. Overall intervention effects were evident for illicit substance use within multiple intervention characteristic subgroups, but not tobacco and alcohol. Such results support the implementation of universal school-based interventions that address 'resilience' protective factors to reduce adolescent illicit substance use, however suggest alternate approaches are required for tobacco and alcohol use. PROSPERO registration: CRD42014004906.

Process evaluation of a sport-for-health intervention to prevent smoking amongst primary school children: SmokeFree Sports

Background

SmokeFree Sports (SFS) was a multi-component sport-for-health intervention aiming at preventing smoking among nine to ten year old primary school children from North West England. The purpose of this study was to evaluate the process and implementation of SFS, examining intervention reach, dose, fidelity, acceptability and sustainability, in order to understand the feasibility and challenges of delivering such interventions and inform interpretations of intervention effectiveness.

Methods

Process measures included: booking logs, 18 focus groups with children (n = 95), semi-structured interviews with teachers (n = 20) and SFS coaches (n = 7), intervention evaluation questionnaires (completed by children, n = 1097; teachers, n = 50), as well direct observations (by researchers, n = 50 observations) and self-evaluations (completed by teachers, n = 125) of intervention delivery (e.g. length of sessions, implementation of activities as intended, children’s engagement and barriers). Descriptive statistics and thematic analysis were applied to quantitative and qualitative data, respectively.

Results

Overall, SFS reached 30.8% of eligible schools, with 1073 children participating in the intervention (across 32 schools). Thirty-one schools completed the intervention in full. Thirty-three teachers (55% female) and 11 SFS coaches (82% male) attended a bespoke SFS training workshop. Disparities in intervention duration (range = 126 to 201 days), uptake (only 25% of classes received optional intervention components in full), and the extent to which core (mean fidelity score of coaching sessions = 58%) and optional components (no adaptions made = 51% of sessions) were delivered as intended, were apparent. Barriers to intervention delivery included the school setting and children’s behaviour and knowledge. SFS was viewed positively (85% and 82% of children and teachers, respectively, rated SFS five out of five) and recommendations to increase school engagement were provided.

Conclusion

SFS was considered acceptable to children, teachers and coaches. Nevertheless, efforts to enhance intervention reach (at the school level), teachers’ engagement and sustainability must be considered. Variations in dose and fidelity likely reflect challenges associated with complex intervention delivery within school settings and thus a flexible design may be necessary. This study adds to the limited scientific evidence base surrounding sport-for-health interventions and their implementation, and suggests that such interventions offer a promising tool for engaging children in activities which promote their health.

School-based programmes for preventing smoking

BACKGROUND

Helping young people to avoid starting smoking is a widely endorsed public health goal, and schools provide a route to communicate with nearly all young people. School-based interventions have been delivered for close to 40 years.

OBJECTIVES

The primary aim of this review was to determine whether school smoking interventions prevent youth from starting smoking. Our secondary objective was to determine which interventions were most effective. This included evaluating the effects of theoretical approaches; additional booster sessions; programme deliverers; gender effects; and multifocal interventions versus those focused solely on smoking.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Tobacco Addiction Group's Specialised Register, MEDLINE, EMBASE, PsycINFO, ERIC, CINAHL, Health Star, and Dissertation Abstracts for terms relating to school-based smoking cessation programmes. In addition, we screened the bibliographies of articles and ran individual MEDLINE searches for 133 authors who had undertaken randomised controlled trials in this area. The most recent searches were conducted in October 2012.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) where students, classes, schools, or school districts were randomised to intervention arm(s) versus a control group, and followed for at least six months. Participants had to be youth (aged 5 to 18). Interventions could be any curricula used in a school setting to deter tobacco use, and outcome measures could be never smoking, frequency of smoking, number of cigarettes smoked, or smoking indices.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for inclusion, extracted data and assessed risk of bias. Based on the type of outcome, we placed studies into three groups for analysis: Pure Prevention cohorts (Group 1), Change in Smoking Behaviour over time (Group 2) and Point Prevalence of Smoking (Group 3).

MAIN RESULTS

One hundred and thirty-four studies involving 428,293 participants met the inclusion criteria. Some studies provided data for more than one group.Pure Prevention cohorts (Group 1) included 49 studies (N = 142,447). Pooled results at follow-up at one year or less found no overall effect of intervention curricula versus control (odds ratio (OR) 0.94, 95% confidence interval (CI) 0.85 to 1.05). In a subgroup analysis, the combined social competence and social influences curricula (six RCTs) showed a statistically significant effect in preventing the onset of smoking (OR 0.49, 95% CI 0.28 to 0.87; seven arms); whereas significant effects were not detected in programmes involving information only (OR 0.12, 95% CI 0.00 to 14.87; one study), social influences only (OR 1.00, 95% CI 0.88 to 1.13; 25 studies), or multimodal interventions (OR 0.89, 95% CI 0.73 to 1.08; five studies). In contrast, pooled results at longest follow-up showed an overall significant effect favouring the intervention (OR 0.88, 95% CI 0.82 to 0.96). Subgroup analyses detected significant effects in programmes with social competence curricula (OR 0.52, 95% CI 0.30 to 0.88), and the combined social competence and social influences curricula (OR 0.50, 95% CI 0.28 to 0.87), but not in those programmes with information only, social influence only, and multimodal programmes.Change in Smoking Behaviour over time (Group 2) included 15 studies (N = 45,555). At one year or less there was a small but statistically significant effect favouring controls (standardised mean difference (SMD) 0.04, 95% CI 0.02 to 0.06). For follow-up longer than one year there was a statistically nonsignificant effect (SMD 0.02, 95% CI -0.00 to 0.02).Twenty-five studies reported data on the Point Prevalence of Smoking (Group 3), though heterogeneity in this group was too high for data to be pooled.We were unable to analyse data for 49 studies (N = 152,544).Subgroup analyses (Pure Prevention cohorts only) demonstrated that at longest follow-up for all curricula combined, there was a significant effect favouring adult presenters (OR 0.88, 95% CI 0.81 to 0.96). There were no differences between tobacco-only and multifocal interventions. For curricula with booster sessions there was a significant effect only for combined social competence and social influences interventions with follow-up of one year or less (OR 0.50, 95% CI 0.26 to 0.96) and at longest follow-up (OR 0.51, 95% CI 0.27 to 0.96). Limited data on gender differences suggested no overall effect, although one study found an effect of multimodal intervention at one year for male students. Sensitivity analyses for Pure Prevention cohorts and Change in Smoking Behaviour over time outcomes suggested that neither selection nor attrition bias affected the results.

AUTHORS' CONCLUSIONS

Pure Prevention cohorts showed a significant effect at longest follow-up, with an average 12% reduction in starting smoking compared to the control groups. However, no overall effect was detected at one year or less. The combined social competence and social influences interventions showed a significant effect at one year and at longest follow-up. Studies that deployed a social influences programme showed no overall effect at any time point; multimodal interventions and those with an information-only approach were similarly ineffective.Studies reporting Change in Smoking Behaviour over time did not show an overall effect, but at an intervention level there were positive findings for social competence and combined social competence and social influences interventions.

When things are not as they appear: assessing the adequacy of cluster randomization when outcome events are rare at baseline

The present study randomly assigned 15 Bahamian elementary schools to one of three intervention conditions. To assess the adequacy of cluster randomization, we examined two concerns identified by the local research team: inequality of gender distribution and environmental risk among groups. Baseline significant differences in risk and protective behaviors were minimal. There were significantly more males in the intervention group. Males had higher rates of risk behavior at all assessments. Poor school performance was also higher among the intervention condition and was significantly associated with increased rates of many but not all risk behaviors. Prior to adjusting for gender and school performance, several risk behaviors appeared to be higher after intervention among intervention youth. Adjusting for gender and school performance eradicated the group differences in risk behavior rates. Results demonstrate the importance of adequate randomization where outcomes of interest are rare events at baseline or differ by gender and there is an unequal gender distribution and the importance of the local research team's knowledge of potential inequalities in environmental risk (i.e., school performance). Not considering such individual differences could impact the integrity of trial outcomes.

Minority participation in a school-based randomized clinical trial of tooth decay prevention in the United States

PURPOSE

To describe the strategies-based on the social triad concept of a partnership of researchers, school personnel and community-employed to recruit low-income, minority parent/caregivers of kindergarten children into a school-based tooth decay prevention trial in the United States.

METHODS

The study site was an urban school district with five elementary schools. Recruitment was carried out once each year for three years. Recruitment involved strategies at the school district, school, classroom, and student-parent level. A coalition of researchers, school personnel and community individuals was established for communication and recruitment. Outreach workers from the community were hired to promote, recruit, and disseminate oral health information. Study promotion included both print materials (logos, flyers, pictorial story boards) and presentations at school and community events.

RESULTS

The School District Superintendent and administrators approved the study, and all five school principals and kindergarten teachers participated. All children within the classrooms were eligible: the overall participation rate of was 86% (580/672). Community outreach workers actively facilitated the recruitment and participants were recruited at open house for parent-teacher meeting (37% of all participants), sending letters and consent forms home (31%), at a prearranged convenient time during drop off and pick up of the child at their respective schools (30%), curriculum nights and health fairs (2%).

CONCLUSION

Utilizing the social triad concept led to success in planning and carrying out the recruitment of predominantly minority school children with high participation rates.

The Active for Life Year 5 (AFLY5) school based cluster randomised controlled trial: study protocol for a randomized controlled trial

Background

Low levels of physical activity, high levels of sedentary behaviour and low levels of fruit and vegetable consumption are common in children and are associated with adverse health outcomes. The aim of this paper is to describe the protocol for a cluster randomised controlled trial (RCT) designed to evaluate a school-based intervention that aims to increase levels of physical activity, decrease sedentary behaviour and increase consumption of fruit and vegetables in school children.

Methods/design

The Active for Life Year 5 (AFLY5) study is a school-based, cluster RCT that targets school children in Year 5 (age 9-10 years). All state junior/primary schools in the area covered by Bristol City and North Somerset Council are invited to participate; special schools are excluded. Eligible schools are randomised to one of two arms: intervention arm (receive the intervention 2011-2012) and control arm (receive the intervention after the final follow-up assessment, 2013-2014). The primary outcomes of the trial are levels of accelerometer assessed physical activity and sedentary behaviour and questionnaire assessed fruit and vegetable consumption. A number of secondary outcomes will also be measured, including body mass index, waist circumference and overweight/obesity. Outcomes will be assessed at baseline (prior to intervention when the children are in Year 4), at the end of intervention 'immediate follow-up' and '12 months long-term' follow-up. We will use random effects linear and logistic regression models to compare outcomes by randomised arm. The economic evaluation from a societal perspective will take the form of a cost consequence analysis. Data from focus groups and interviews with pupils, parents and teachers will be used to increase understanding of how the intervention has any effect and is integrated into normal school activity.

Discussion

The results of the trial will provide information about the public health effectiveness of a school-based intervention aimed at improving levels of physical activity, sedentary behaviour and diet in children.

Trial registration

ISRCTN50133740

Parental smoking cessation and child daily smoking: A 9-year longitudinal study of mediation by child cognitions about smoking

OBJECTIVE

This study investigated to what extent the prospective relationship between parental smoking cessation and child daily smoking is mediated by child cognitions about smoking.

DESIGN

The study drew its sample from the 40 Washington State school districts involved in the Hutchinson Smoking Prevention Project. The predictor variable of parental smoking cessation was measured during third grade. The mediator measures, consistent with the Theory of Planned Behavior and Social Cognitive Theory, were measured during ninth grade, and the smoking status outcome was measured during twelfth grade.

MAIN OUTCOME MEASURES

Smoking status at twelfth grade.

RESULTS

Negative general attitudes toward smoking, attitude that cigarette smoke is bothersome, and tobacco refusal self-efficacy together significantly mediated 49% of the prospective relationship between parental smoking cessation and child daily smoking.

CONCLUSION

Parental smoking cessation before children reach third grade may lead children to develop more negative cognitions about smoking, and, in turn, reduce their risk of smoking.

Implementing school malaria surveys in Kenya: towards a national surveillance system

Objective

To design and implement surveys of malaria infection and coverage of malaria control interventions among school children in Kenya in order to contribute towards a nationwide assessment of malaria.

Methods

The country was stratified into distinct malaria transmission zones based on a malaria risk map and 480 schools were visited between October 2008 and March 2010. Surveys were conducted in two phases: an initial opportunistic phase whereby schools were selected for other research purposes; and a second phase whereby schools were purposively selected to provide adequate spatial representation across the country. Consent for participation was based on passive, opt-out consent rather than written, opt-in consent because of the routine, low-risk nature of the survey. All children were diagnosed for Plasmodium infection using rapid diagnostic tests, assessed for anaemia and were interviewed about mosquito net usage, recent history of illness, and socio-economic and household indicators. Children's responses were entered electronically in the school and data transmitted nightly to Nairobi using a mobile phone modem connection. RDT positive results were corrected by microscopy and all results were adjusted for clustering using random effect regression modelling.

Results

49,975 children in 480 schools were sampled, at an estimated cost of US$ 1,116 per school. The overall prevalence of malaria and anaemia was 4.3% and 14.1%, respectively, and 19.0% of children reported using an insecticide-treated net (ITN). The prevalence of infection showed marked variation across the country, with prevalence being highest in Western and Nyanza provinces, and lowest in Central, North Eastern and Eastern provinces. Nationally, 2.3% of schools had reported ITN use >60%, and low reported ITN use was a particular problem in Western and Nyanza provinces. Few schools reported having malaria health education materials or ongoing malaria control activities.

Conclusion

School malaria surveys provide a rapid, cheap and sustainable approach to malaria surveillance which can complement household surveys, and in Kenya, show that large areas of the country do not merit any direct school-based control, but school-based interventions, coupled with strengthened community-based strategies, are warranted in western and coastal Kenya. The results also provide detailed baseline data to inform evaluation of school-based malaria control in Kenya.

Parents who quit smoking and their adult children's smoking cessation: a 20-year follow-up study

AIMS

Extending our earlier findings from a longitudinal cohort study, this study examines parents' early and late smoking cessation as predictors of their young adult children's smoking cessation.

DESIGN

Parents' early smoking cessation status was assessed when their children were aged 8 years; parents' late smoking cessation was assessed when their children were aged 17 years. Young adult children's smoking cessation, of at least 6 months duration, was assessed at age 28 years.

SETTING

Forty Washington State school districts.

PARTICIPANTS AND MEASUREMENTS

Participants were 991 at least weekly smokers at age 17 whose parents were ever regular smokers and who also reported their smoking status at age 28. Questionnaire data were gathered on parents and their children (49% female and 91% Caucasian) in a longitudinal cohort (84% retention).

FINDINGS

Among children who smoked daily at age 17, parents' quitting early (i.e. by the time their children were aged 8) was associated with a 1.7 times higher odds of these children quitting by age 28 compared to those whose parents did not quit [odds ratio (OR) 1.70; 95% confidence interval (CI) 1.23, 2.36]. Results were similar among children who smoked weekly at age 17 (OR 1.91; 95% CI 1.41, 2.58). There was a similar, but non-significant, pattern of results among those whose parents quit late.

CONCLUSIONS

Supporting our earlier findings, results suggest that parents' early smoking cessation has a long-term influence on their adult children's smoking cessation. Parents who smoke should be encouraged to quit when their children are young.

Therapy for specific problems: youth tobacco cessation

Cigarette smoking is the leading cause of premature morbidity and mortality in the United States. The majority of children smoke their first cigarette in early adolescence, and many older teens have well-established dependence on nicotine. Efforts to promote and support smoking cessation among these youth smokers are critical. The available experimental studies of youth cessation interventions find that behavioral interventions increase the chances of youth smokers achieving successful cessation. Currently there is insufficient evidence for the effectiveness of pharmacological treatments with youth smokers. Many innovative studies have been compromised by challenges in recruiting sufficient numbers of youth, obtaining approval for waivers of parental consent, and high attrition in longitudinal studies. Key areas for future work include bridging the fields of adolescent development and treatment design, matching treatments to developmental trajectories of smoking behavior, better understanding treatment processes and treatment moderators, and building demand for evidence-based cessation treatments.

[Interventions aimed at adolescents to stop smoking: the "Today, I don' t smoke" programme in high schools in the Paris metropolitan region]

Tobacco use is in itself a public health issue, but it also represents an identified entry point to the consumption of other toxic products. The key age group for initial consumption is that around the end of junior high school and the beginning of high school, when students' high level of autonomy is combined with a new set of educational circumstances and challenges. Intervening in a school or educational setting is not easy and often criticized. This programme involved around fifty secondary schools in the greater Paris metropolitan region, followed over several years, benefiting from substantial evaluation, including evaluation of results. The action combines a collective intervention in the classrooms coupled with the availability of a CO-testing stand to which the young people have open access. Several tools were created, including tools for evaluation. Significant preparation work and the creation and strengthening of solid partnerships were necessary, with a very strong investment in sustainability. The positive results which have been observed allow for the consideration of transfer methods for reproducing the activity combining two approaches into a repetitive and continuous process.

Free breakfasts in schools: design and conduct of a cluster randomised controlled trial of the Primary School Free Breakfast Initiative in Wales [ISRCTN18336527]

Background

School-based breakfast provision is increasingly being seen as a means of improving educational performance and dietary behaviour amongst children. Furthermore, recognition is growing that breakfast provision offers potential as a means of addressing social inequalities in these outcomes. At present however, the evidence base on the effectiveness of breakfast provision in bringing about these improvements is limited.

Methods/Design

This paper describes the research design of a large scale evaluation of the effectiveness of the Welsh Assembly Government's Primary School Free Breakfast Initiative. A cluster randomised trial, with school as the unit of randomisation was used for the outcome evaluation, with a nested qualitative process evaluation. Quantitative outcome measures included dietary habits, attitudes, cognitive function, classroom behaviour, and school attendance. The study recruited 111 primary schools in Wales, of which 56 were randomly assigned to control condition and 55 to intervention. Participants were Year 5 and 6 students (aged 9–11 years) in these schools. Data were collected for all 111 schools at each of three time points: baseline, 4 month and 12 month follow-up. This was achieved through a repeated cross-sectional survey of approximately 4350 students on each of these occasions. Of those students in Year 5 at baseline, 1975 provided data at one or both of the follow-ups, forming a nested cohort. The evaluation also included a nested process evaluation, using questionnaires, semi-structured interviews and case studies with students, school staff, and local authority scheme coordinators as key informants.

Discussion

An overview of the methods used for the evaluation is presented, providing an example of the feasibility of conducting robust evaluations of policy initiatives using a randomised trial design with nested process evaluation. Details are provided of response rates and the flow of participants. Reflection is offered on methodological issues encountered at various stages through the course of the study, focusing upon issues associated with conducting a randomised trial of a government policy initiative, and with conducting research in school settings.

Trial registration

Current Controlled Trials ISRCTN18336527

Study design: the basics

In biomedical research, meaningful conclusions can only be drawn based on data collected from a valid scientific design using appropriate statistical methods. Therefore, the selection of an appropriate study design is important in order to provide an unbiased and scientific evaluation of the research questions. In this chapter, the different kinds of experimental studies commonly used in biology and medicine are introduced. A brief survey of basic experimental study designs, randomization, blinding, possible biases, issues in data analysis, and interpretation of the study results are mainly provided.

School-based programmes for preventing smoking

BACKGROUND

Smoking rates in adolescents are rising in some countries. Helping young people to avoid starting smoking is a widely endorsed goal of public health, but there is uncertainty about how to do this. Schools provide a route for communicating with a large proportion of young people, and school-based programmes for smoking prevention have been widely developed and evaluated.

OBJECTIVES

To review all randomized controlled trials of behavioural interventions in schools to prevent children (aged 5 to12) and adolescents (aged 13 to18) starting smoking.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Tobacco Addiction Group's Specialized Register, MEDLINE, EMBASE, PsyclNFO, ERIC, CINAHL, Health Star, Dissertation Abstracts and studies identified in the bibliographies of articles. Individual MEDLINE searches were made for 133 authors who had undertaken randomized controlled trials in this area.

SELECTION CRITERIA

Types of studies: those in which individual students, classes, schools, or school districts were randomized to the intervention or control groups and followed for at least six months.

TYPES OF PARTICIPANTS

Children (aged 5 to12) or adolescents (aged 13 to18) in school settings. Types of interventions: Classroom programmes or curricula, including those with associated family and community interventions, intended to deter use of tobacco. We included programmes or curricula that provided information, those that used social influences approaches, those that taught generic social competence, and those that included interventions beyond the school into the community. We included programmes with a drug or alcohol focus if outcomes for tobacco use were reported. Types of outcome measures: Prevalence of non-smoking at follow up among those not smoking at baseline. We did not require biochemical validation of self-reported tobacco use for study inclusion.

DATA COLLECTION AND ANALYSIS

We assessed whether identified citations were randomized controlled trials. We assessed the quality of design and execution, and abstracted outcome data. Because of the marked heterogeneity of design and outcomes, we computed pooled estimates only for those trials that could be analyzed together and for which statistical data were available. We predominantly synthesized the data using narrative systematic review. We grouped studies by intervention method (information; social competence; social influences; combined social influences/social competence; multi-modal programmes). Within each group, we placed them into three categories (low, medium and high risk of bias) according to validity using quality criteria for reported study design.

MAIN RESULTS

Of the 94 randomized controlled trials identified, we classified 23 as category one (most valid). There was one category one study of information-giving and two of teaching social comeptence. There were thirteen category one studies of social influences interventions. Of these, nine found some positive effect of intervention on smoking prevalence, and four failed to detect an effect on smoking prevalence. The largest and most rigorous study, the Hutchinson Smoking Prevention Project, found no long-term effect of an intensive eight-year programme on smoking behaviour. There were three category one RCTs of combined social influences and social competence interventions: one provided significant results and one only for instruction by health educators compared to self-instruction. There was a lack of high quality evidence about the effectiveness of combinations of social influences and social competence approaches. There was one category one study providing data on social influences compared with information giving. There were four category one studies of multi-modal approaches but they provided limited evidence about the effectiveness of multi-modal approaches including community initiatives.

AUTHORS' CONCLUSIONS

There is one rigorous test of the effects of information-giving about smoking. There are well-conducted randomized controlled trials to test the effects of social influences interventions: in half of the group of best quality studies those in the intervention group smoke less than those in the control, but many studies failed to detect an effect of the intervention. There are only three high quality RCTs which test the effectiveness of combinations of social influences and social competence interventions, and four which test multi-modal interventions; half showed significant positive results.

Nine-year prediction of adolescent smoking by number of smoking parents

For scientific and public health reasons, it is important to identify the role of family influences on child smoking acquisition. Using a well-followed (>90%) cohort of 3,012 children and their parents, this study prospectively investigated the influence of smoking by 0 vs. 1 vs. 2 parents when the children were young (3rd grade), on whether the children subsequently became daily smokers. It is the only study to investigate the prediction of child/adolescent smoking at the end of the smoking acquisition period (12th grade) by parental smoking at the start of the period (3rd grade). Logistic regression analyses revealed that having one parent who smokes substantially increases the risk that children will become daily smokers, relative to families where neither parent smokes (OR=1.90, p<.01). There is no evidence that the increased risk depends on parent or child gender. These results suggest the need for public health interventions that inform parents of young children that their own smoking behavior increases their children's risk for future smoking.

Recruitment and retention of adolescents in a smoking trajectory study: who participates and lessons learned

Recruitment of adolescents into tobacco use research is often challenging. This study reports on the predictors of recruitment and retention in a longitudinal study of adolescent smoking behavior. In 2000, 8th and 10th grade students at 18 schools (N = 5,298) in the Chicago metropolitan area completed brief screening surveys; 1457 students (ranging from susceptible nonsmokers to regular smokers) were invited to participate in a longitudinal study, and 48.9% agreed. Chi-square analyses revealed that female and white students were more likely to participate than male and nonwhite students. Recruitment rates did not vary by parental smoking status, students' experience with smoking, or student grade. Multivariate analyses revealed that overall, gender and race were significant predictors of participation. Chi-square and multivariate analyses revealed no significant differences in retention on the demographic, smoking experience, or psychosocial variables measured. Implications of the results and study limitations are discussed.

Parental smoking cessation and children's smoking: Mediation by antismoking actions

The present study investigated whether parents' antismoking actions mediated the prospective relationship between parental smoking cessation and children's smoking. Smoking status of parents (predictor) was assessed when their children were in 3rd grade, parental antismoking actions (mediators) were assessed when their children were in 11th grade, and children's smoking status (outcome) was assessed when they were in 12th grade. In 20 Washington state school districts, data were collected from 1,600 children (49% female, 91% White) and from their parents. Results showed that children's odds of daily smoking were reduced by 39% (95% CI = 24%-51%) for those whose parents had quit smoking, compared with those whose parents were current smokers. Asking to sit in nonsmoking sections of public establishments was a significant (p<.01) mediator that explained 64% of the association between parental smoking cessation and children's smoking. However, not allowing smoking in the home and asking others not to smoke around them were not significant mediators (p = .10, and p = .06, respectively). In conclusion, asking to sit in a nonsmoking section of a public establishment substantially mediates the relationship between parental smoking cessation and children's smoking.

Rationale, design and conduct of a comprehensive evaluation of a school-based peer-led anti-smoking intervention in the UK: the ASSIST cluster randomised trial [ISRCTN55572965]

BACKGROUND

To date, no school-based intervention has been proven to be effective in preventing adolescent smoking, despite continuing concern about smoking levels amongst young people in the United Kingdom. Although formal teacher-led smoking prevention interventions are considered unlikely to be effective, peer-led approaches to reducing smoking have been proposed as potentially valuable.

METHODS/DESIGN

ASSIST (A Stop Smoking in Schools Trial) is a comprehensive, large-scale evaluation to rigorously test whether peer supporters in Year 8 (age 11-12) can be recruited and trained to effect a reduction in smoking uptake among their fellow students. The evaluation is employing a cluster randomised controlled trial (RCT) design with secondary school as the unit of randomisation, and is being undertaken in 59 schools in South East Wales and the West of England. Embedded within the trial are an economic evaluation of the intervention costs, a process evaluation to provide detailed information on how the intervention was delivered and received, and an analysis of social networks to consider whether such a peer group intervention could work amongst schoolchildren in this age group. Schools were randomised to either continue with normal smoking education (n = 29 schools, 5562 students), or to do so and additionally receive the ASSIST intervention (n = 30 schools, 5481 students). No schools withdrew once the trial had started, and the intervention was successfully implemented in all 30 schools, with excellent participation rates from the peer supporters. The primary outcome is regular (weekly) smoking, validated by salivary cotinine, and this outcome has been obtained for 94.4%, 91.0% and 95.6% of eligible students at baseline, immediate post-intervention, and one-year follow-up respectively.

DISCUSSION

Comprehensive evaluations of complex public health interventions of this scale and nature are rare in the United Kingdom. This paper demonstrates the feasibility of conducting cluster RCTs of complex public health interventions in schools, and how the rigour of such designs can be maximised both by thorough implementation of the protocol and by broadening the scope of questions addressed in the trial by including additional evaluative components.

Does parental smoking cessation encourage their young adult children to quit smoking? A prospective study

AIMS

To investigate the extent to which parental early and late smoking cessation predicts their young adult children's smoking cessation.

DESIGN

Parental early smoking cessation status was assessed when children were in 3rd grade, parental late smoking cessation was assessed when children were in 11th grade, and young adult children's smoking cessation was assessed 2 years after high school.

SETTING

Forty Washington State school districts participated in the Hutchinson Smoking Prevention Project.

PARTICIPANTS AND MEASUREMENTS

Participants were the 1553 families in which parents were ever regular smokers who had a young adult child smoking at least weekly at 12th grade who also reported their smoking status 2 years later. Questionnaire data were gathered on parents and their young adult children (49% female and 91% Caucasian) in a cohort with a 94% retention rate.

FINDINGS

Parents who quit early had children with 1.8 (OR = 1.80; 95% CI = 1.22, 2.64) times higher odds of quitting smoking for at least 1 month in young adulthood compared to those whose parents did not quit early. In contrast, there was no association (OR = 0.84; 95% CI = 0.47, 1.51) between parents quitting late and their young adult children's smoking cessation.

CONCLUSIONS

Parental early smoking cessation is associated with increased odds of their young adult children's smoking cessation. Parents who smoke should be encouraged to quit when their children are young.

Mounting a community-randomized trial: sample size, matching, selection, and randomization issues in PRISM

This paper discusses some of the processes for establishing a large cluster-randomized trial of a community and primary care intervention in 16 local government areas in Victoria, Australia. The development of the trial in terms of design factors such as sample size estimates and the selection and randomization of communities to intervention or comparison is described. The intervention program to be implemented in Program of Resources, Information and Support for Mothers (PRISM) was conceived as a whole community approach to improving support for all mothers in the first 12 months after birth. A cluster-randomized trial was thus the design of choice from the outset. With a limited number of communities available, a matched-pair design with eight pairs was chosen. Sample size estimates, adjusting for the cluster randomization and the pair-matched design, showed that with eight pairs, on average, 800 women from each community would need to respond to provide sufficient power to determine a 3% reduction in the prevalence of maternal depression 6 months after birth-a reduction deemed to be a worthwhile impact of the intervention to be reliably detected at 80% power. The process of selecting suitable communities and matching them into pairs required careful collection of data on numbers of births, size of the local government areas (LGAs), and an assessment of the capacity of communities to implement the intervention. Ways of dealing with boundary issues associated with potential contamination are discussed. Methods for the selection of feasible configurations of sets of pairs and the ultimate allocation to intervention or comparison are provided in detail. Ultimately, all such studies are a balancing act between selecting the minimum number of communities to detect a meaningful outcome effect of an intervention and the maximum size budget and other resources allow.

Nine-year prospective association between older siblings' smoking and children's daily smoking

PURPOSE

To explore the hypothesis that older siblings' smoking, after controlling for parents' smoking, influences children's smoking.

METHODS

Study participants were 2981 students in the control cohort of a school-based smoking prevention randomized trial for whom parents' smoking and older siblings' smoking data were collected at 3rd grade and daily smoking data was assessed 9 years later through a self-report questionnaire at the 12th grade. Data were analyzed using conditional logistic regression and likelihood ratio tests.

RESULTS

For families in which no parent smoked, the 12th grade prevalence of daily smoking was 31% when at least one older sibling smoked compared to 18% when no older sibling smoked. For families in which at least one parent smoked, the 12th grade prevalence of daily smoking was 41% when at least one older sibling smoked compared to 29% when no older sibling smoked. There was a substantial increase in the odds (OR = 1.60, p =.004) of children's daily smoking at 12th grade when their older siblings smoked, even after adjusting for parents' smoking.

CONCLUSIONS

Older siblings' smoking is associated with increased risk of children's smoking after adjusting for parents smoking. Furthermore, there was no evidence to suggest that the influence of older siblings' smoking was different in families where no parent smoked compared to those where at least one parent smoked. Also, there was no evidence that the influence of older siblings' smoking was different in boys vs. girls.

Mothers' attitudes and concerns about their children smoking: do they influence kids?

BACKGROUND

The effects of mothers' attitudes and concerns about tobacco use on whether their children take up smoking are largely unknown. This study examined the predictive effects of mothers' attitudes about tobacco and concerns about their children smoking.

METHODS

Self-reported data from a large number of 12th-grade students (2,736) and their mothers were used. Mothers' attitudes and concerns were assessed when their children were 3rd graders (age 8), at the start of the smoking acquisition period; their children were then followed prospectively (with attrition of only 5%) for 9 years to the end of the period (12th grade) for the assessment of smoking behavior.

RESULTS

In households in which both parents are nonsmokers, strong maternal antismoking attitudes are associated with a statistically significant approximately 50% reduction (P < 0.05) in the prevalence of smoking by adolescent children. In contrast, in households in which one or both parents are current smokers, there was no reduction in adolescent smoking associated with mothers' antismoking attitudes.

CONCLUSIONS

Maternal antismoking attitudes when their children are young predict adolescents' adoption of smoking at 12th grade, but only when parental behavior is consistent with these attitudes.

School-based programmes for preventing smoking

BACKGROUND

Smoking rates in adolescents are rising. Helping young people to avoid starting smoking is a widely endorsed goal of public health, but there is uncertainty about how to do this. Schools provide a route for communicating with a large proportion of young people, and school-based programmes for smoking prevention have been widely developed and evaluated.

OBJECTIVES

To review all randomised controlled trials of behavioural interventions in schools to prevent children (aged 5 to12) and adolescents (aged 13 to18) starting smoking.

SEARCH STRATEGY

We searched The Cochrane Controlled Trials and Tobacco Review group registers, MEDLINE, EMBASE, Psyclnfo, ERIC, CINAHL, Health Star, Dissertation Abstracts and studies identified in the bibliographies of articles. Individual MEDLINE searches were made for 133 authors who had undertaken randomised controlled trials in this area.

SELECTION CRITERIA

Types of studies: those in which individual students, classes, schools, or school districts were randomised to the intervention or control groups and followed for at least six months.

TYPES OF PARTICIPANTS

Children (aged 5 to12) or adolescents (aged 13 to18) in school settings. Types of interventions: Classroom programmes or curricula, including those with associated family and community interventions, intended to deter use of tobacco. We included programmes or curricula that provided information, those that used social influences approaches, those that taught generic social competence, and those that included interventions beyond the school into the community. We included programmes with a drug or alcohol focus if outcomes for tobacco use were reported. Types of outcome measures: Prevalence of non-smoking at follow-up among those not smoking at baseline. We did not require biochemical validation of self-reported tobacco use for study inclusion.

DATA COLLECTION AND ANALYSIS

We assessed whether identified citations were randomised controlled trials. We assessed the quality of design and execution, and abstracted outcome data. Because of the marked heterogeneity of design and outcomes, we did not perform a meta-analysis. We synthesised the data using narrative systematic review. We grouped studies by intervention method (information; social competence; social influences; combined social influences/social competence and multi-modal programmes). Within each category, we placed them into three groups according to validity using quality criteria for reported study design.

MAIN RESULTS

Of the 76 randomised controlled trials identified, we classified 16 as category one (most valid). There were no category one studies of information giving alone. There were fifteen category one studies of social influences interventions. Of these, eight showed some positive effect of intervention on smoking prevalence, and seven failed to detect an effect on smoking prevalence. The largest and most rigorous study, the Hutchinson Smoking Prevention Project, found no long-term effect of an intensive 8-year programme on smoking behaviour. There was a lack of high quality evidence about the effectiveness of combinations of social influences and social competence approaches. There was limited evidence about the effectiveness of multi-modal approaches including community initiatives.

REVIEWER'S CONCLUSIONS

There is no rigorous test of the effects of information giving about smoking. There are well-conducted randomised controlled trials to test the effects of social influences interventions: in half of the group of best quality studies those in the intervention group smoke less than those in the control, but many studies showed no effect of the intervention. There is a lack of high-quality evidence about the effectiveness of combinations of social influences and social competence interventions, and of multi-modal programmes that include community interventions.

Selected statistical issues in group randomized trials

Group randomized trials (GRTs) in public health research typically use a small number of randomized groups with a relatively large number of participants per group. Two fundamental features characterize GRTs: a positive correlation of outcomes within a group, and the small number of groups. Appropriate consideration of these fundamental features is essential for design and analysis. This paper presents the fundamental features of GRTs and the importance of considering these features in design and analysis. It also reviews and contrasts the main analytic methods proposed for GRTs, emphasizing the assumptions required to make these methods valid and efficient. Also discussed are various design issues, along with guidelines for choosing among them. A real data example illustrates these issues and methods.