An informal school-based peer-led intervention for smoking prevention in adolescence (ASSIST): a cluster randomised trial

The changing role of self-efficacy in adolescent smoking initiation

BACKGROUND

Refusal self-efficacy is assumed to be linked to adolescent smoking. The aim of the present study was to examine the changing role of self-efficacy in adolescent smoking over time while controlling for parental, sibling, and friends' smoking.

METHODS

This study used data from five annual waves of the "Family and Health" project. A total of 428 adolescents (mean age = 13.3 years; standard deviation = .48) and their parents participated at baseline. Only never smokers at baseline (n = 272) were included to measure smoking initiation. First, the effects of baseline self-efficacy, parental, sibling, and friends' smoking on adolescent smoking initiation at measurement five were examined. Second, with latent growth curves analyses, individual growth curve parameters of adolescent smoking, self-efficacy, parental, sibling, and friends' smoking were calculated. Subsequently, these growth parameters were used to predict growth of adolescent smoking.

RESULTS

Findings showed that baseline self-efficacy, parental and friends' smoking did not predict adolescent smoking at wave five, but baseline sibling smoking did. However, growth curve parameters showed that a decrease in self-efficacy, an increase in proportion of smoking friends, and an increase in sibling smoking over time were related to an increase in adolescent smoking. Initial levels of sibling and friends' smoking moderated the link between self-efficacy and adolescent smoking over time.

CONCLUSION

A decrease in self-efficacy over time, rather than baseline self-efficacy, is associated with smoking initiation in adolescence. Findings emphasize the need for more fine-grained analyses when looking at self-efficacy or other individual characteristics that might fluctuate over time.

Ifugao males, learning and teaching for the improvement of maternal and child health status in the Philippines: an evaluation of a program

Background

Improving Maternal and Child Health (MCH) is a prioritized global agenda in achieving the United Nations Millennium Development Goal 5. In this challenge, involving males has been an important agenda, and a program with such intent was conducted in Alfonso Lista, Ifugao, of the Philippines. The objectives of this study were: (1) to evaluate the effectiveness in knowledge, attitude, and practice before and after a MCH session; (2) to evaluate the session's effectiveness in relation to socio-demographic characteristics; and (3) to examine if males who have learned about MCH topics can teach another group of males.

Methods

A male community representative who received a lecture from the health office staff was assigned to teach a group of community males [Group 1, N = 140] in 5 sessions, using educational materials. 10 male volunteers from Group 1 then taught a different group of males [Group 2, N = 105] in their own barangays (villages). To evaluate its effectiveness, a self-administered questionnaire survey pertaining knowledge, attitude and practice regarding MCH was conducted at three different time points: before the session (Time 1, T1), after the session (Time 2, T2), and 3 months following the session (Time 3, T3). A repeated measures analysis of variance was conducted to test for changes over time and its interaction effect between specific socio-demographic variables.

Results

In Group 1, there was a significant positive increase in knowledge score over time at T1-T2 and T1-T3 (p < 0.001). For attitude, the score increased only at T1-T2 (p = 0.027). The effectiveness in knowledge and attitude did not vary by socio-demographic characteristics. As for practice, majority of the participants reported that they had talked about MCH topics in their community and assisted a pregnant woman in some ways. A comparison between Group 1 and Group 2 revealed that Group 2 had similar effectiveness as Group 1 in knowledge improvement immediately after the session (p < 0.001), but no such improvement in the attitude score.

Conclusion

Although the change in attitude needs further assessment, this strategy of continuous learning and teaching of MCH topics within community males is shown to improve knowledge and has a potential to uplift the MCH status, including the reduction of maternal deaths, in Alfonso Lista, Ifugao, Philippines.

No smoke without fire: The impact of future friends on adolescent smoking behaviour

OBJECTIVE

This study examined the impact of future friends and the contribution of different social influence and selection processes in predicting adolescents' smoking behaviour by extending the theory of planned behaviour (TPB). We investigated the impact of previous smoking, direct pressure from friends, descriptive norms of present and future friends, smoking-based selection of future friends, and distinguished between reciprocal and desired friends.

DESIGN

A longitudinal design with three measurements was used. METHODSL: The sample consisted of 1,475 Dutch high school students (mean age = 12.7 years) that participated as a control group in the European Smoking prevention Framework Approach study at three measurements.

RESULTS

Structural equation modelling revealed that adolescent smoking was influenced by intention, previous smoking, descriptive norms of parents and siblings, and that desired as well as reciprocal friends were selected based on similar smoking behaviour. Future friends indirectly influenced adolescent smoking through intention, as did attitude, subjective norms of parents and siblings, previous smoking, and descriptive norms of reciprocal friends and siblings.

CONCLUSIONS

The present results suggest that descriptive norms and selection of friends need to be considered as major factors explaining smoking behaviour among adolescents besides the TPB components. These insights contribute to the further refinement of smoking prevention strategies.

Efetividade de uma intervenção educacional em tabagismo entre adolescentes escolares

O objetivo do estudo foi avaliar a efetividade de um programa educacional sobre tabagismo desenvolvido pelo Instituto Nacional do Câncer em adolescentes escolares de Pelotas, RS. Das 46 escolas públicas da cidade, 32 foram sorteadas aleatoriamente e, posteriormente, randomizadas em grupo controle ou intervenção. Em ambas as fases do estudo (pré e pós-intervenção), os estudantes de 7ª e 8ª série responderam a um questionário, e uma amostra de urina foi coletada para análise de cotinina. A intervenção educativa teve duração de seis meses. Os desfechos estudados foram: "auto-relato de uso de cigarros nos últimos 30 dias" e "concentração de cotinina na urina (categorizada em > 10 ng/ml e > 30 ng/ml)". A intervenção não provocou mudança na prevalência de tabagismo, tanto mensurado por auto-relato como pela concentração de cotinina. No entanto, o conhecimento dos alunos acerca dos malefícios do cigarro aumentou no grupo intervenção. Em resumo, não houve efetividade da intervenção educacional para mudanças de comportamento, mas houve melhora no conhecimento dos prejuízos do fumo.

Preliminary healthy eating outcomes of SNaX, a pilot community-based intervention for adolescents

PURPOSE

We used principles of community-based participatory research to develop and pilot test a 5-week intervention for middle school students, Students for Nutrition and eXercise (SNaX). SNaX aimed to translate school obesity-prevention policies into practice with peer advocacy of healthy eating and school cafeteria changes.

METHODS

A total 425 seventh graders (63% of all seventh graders) in the intervention school were surveyed at baseline regarding cafeteria attitudes and sugar-sweetened beverage consumption; of the 425 students, 399 (94%) were surveyed again at 1-month post-intervention. School cafeteria records were obtained from two schools: the intervention school and a nonrandomized selected comparison school with similar student socio-demographic characteristics.

RESULTS

A total of 140 students in the intervention school were trained as peer advocates. In the intervention school, cafeteria attitudes among peer advocates significantly improved over time (approximately one-third of a standard deviation), whereas cafeteria attitudes of non-peer advocates remained stable; the improvement among peer advocates was significantly greater than the pre-post-change for non-peer advocates (b = .71, p < .001). Peer advocates significantly reduced their sugar-sweetened beverage intake (sports and fruit drinks), from 33% before intervention to 21% after intervention (p = .03). Cafeteria records indicated that servings of fruit and healthier entrées (salads, sandwiches, and yogurt parfaits) significantly decreased in the comparison school and significantly increased in the intervention school; the magnitude of changes differed significantly between the schools (p < .001).

CONCLUSIONS

As compared with the non-peer advocates, peer advocates appeared to benefit more from the intervention. Future research should consider engaging parents, students, and other key community stakeholders to determine acceptable and sustainable cafeteria changes.

"How can I not?": men's pathways to involvement in anti-violence against women work

Despite growing male participation in ending violence against women, little is known about the factors that precipitate men's engagement as antiviolence "allies." This study presents findings from a qualitative analysis of interviews with 27 men who recently initiated involvement in an organization or event dedicated to ending sexual or domestic violence. Findings suggest that men's engagement is a process that occurs over time, that happens largely through existing social networks, and that is influenced by exposure to sensitizing experiences, tangible involvement opportunities and specific types of meaning making related to violence. Implications for models of ally development and for efforts to engage men in antiviolence work are discussed.

Assessing and accounting for time heterogeneity in stochastic actor oriented models

This paper explores time heterogeneity in stochastic actor oriented models (SAOM) proposed by Snijders (Sociological Methodology. Blackwell, Boston, pp 361-395, 2001) which are meant to study the evolution of networks. SAOMs model social networks as directed graphs with nodes representing people, organizations, etc., and dichotomous relations representing underlying relationships of friendship, advice, etc. We illustrate several reasons why heterogeneity should be statistically tested and provide a fast, convenient method for assessment and model correction. SAOMs provide a flexible framework for network dynamics which allow a researcher to test selection, influence, behavioral, and structural properties in network data over time. We show how the forward-selecting, score type test proposed by Schweinberger (Chapter 4: Statistical modeling of network panel data: goodness of fit. PhD thesis, University of Groningen 2007) can be employed to quickly assess heterogeneity at almost no additional computational cost. One step estimates are used to assess the magnitude of the heterogeneity. Simulation studies are conducted to support the validity of this approach. The ASSIST dataset (Campbell et al. Lancet 371(9624):1595-1602, 2008) is reanalyzed with the score type test, one step estimators, and a full estimation for illustration. These tools are implemented in the RSiena package, and a brief walkthrough is provided.

Evaluating the impact of a school-based helmet promotion program on eligible adolescent drivers: different audiences, different needs?

The school environment has been often identified as a prosperous venue for public health improvement. This study is a cluster randomized controlled trial evaluating the impact of a school-based helmet promotion program on knowledge, attitudes and practices of eligible adolescent drivers. Four public, four private and four vocational high schools situated in Attica, Greece, were sorted by type and randomly assigned to receive a 1-month intervention, based on the concepts of the Health Belief Model, or serve as controls. Self-report data were collected at baseline from 741 second grade students (∼16 years) and immediately after program completion. Linear mixed models with random student effects were used to estimate mean changes in scores for each treatment group and corresponding between groups differences of changes. Likelihood-based analysis showed that the intervention yielded a significant improvement in knowledge about helmet use. Yet, its impact on attitudes and practices appeared to vary across different school types. With current research offering ambiguous results on the appropriate timing of injury prevention efforts, this study suggests that educational programs targeting road safety can lead to positive changes if tailored to the needs of specific population groups and implemented during critical life periods, such as the transition to driving status.

Prevention of HIV infection for people who inject drugs: why individual, structural, and combination approaches are needed

HIV can spread rapidly between people who inject drugs (through injections and sexual transmission), and potentially the virus can pass to the wider community (by sexual transmission). Here, we summarise evidence on the effectiveness of individual-level approaches to prevention of HIV infection; review global and regional coverage of opioid substitution treatment, needle and syringe programmes, and antiretroviral treatment; model the effect of increased coverage and a combination of these three approaches on HIV transmission and prevalence in injecting drug users; and discuss evidence for structural-level interventions. Each intervention alone will achieve modest reductions in HIV transmission, and prevention of HIV transmission necessitates high-coverage and combined approaches. Social and structural changes are potentially beneficial components in a combined-intervention strategy, especially when scale-up is difficult or reductions in HIV transmission and injection risk are difficult to achieve. Although further evidence is needed on how to optimise combinations of interventions in different settings and epidemics, we know enough now about which actions are effective: the challenge is to deliver these well and to scale.

The relative importance of different measures of peer smoking on adolescent smoking behavior: cross-sectional and longitudinal analyses of a large British cohort

PURPOSE

To examine the relative importance of smoking behavior of best friends, boyfriends/girlfriends, the wider friendship group, and school year group smoking prevalence as correlates and predictors of smoking behavior (peer influence). The article also aims to assess the relative extent to which smoking behavior is associated with changes in smoking among peers who are selected to be friends (selective association).

METHODS

Using two waves of data collected from 4,145 year 8 (12-13 years) and year 9 (13-14 years) students in 29 schools, logistic regression models estimated the cross-sectional association between four year 8 peer influence variables and weekly and occasional smoking, and the extent to which these peer influence variables and three selective association variables were predictors of weekly smoking in year 9.

RESULTS

The smoking behavior of best friend, boyfriend/girlfriend, the wider friendship group, and school year group prevalence were cross-sectionally associated with higher odds of weekly and occasional smoking. In longitudinal multivariate influence models, only the smoking behavior of boyfriend/girlfriend and the wider friendship group were associated with weekly smoking. Weekly smoking was associated with maintaining or changing to having smokers among best friends, boyfriends/girlfriends, and the wider friendship group. In models including all variables, only selective association effects were observed.

CONCLUSIONS

Although univariate analyses indicate an association of friends', peer group, and year group smoking with current and subsequent smoking behavior, multivariate longitudinal analyses indicate that simple peer influence models do not completely explain adolescent smoking and that a more complex interrelationship exists between smoking, peer's smoking and peer socialization.

Smoking-based selection and influence in gender-segregated friendship networks: a social network analysis of adolescent smoking

AIMS

The main goal of this study was to examine differences between adolescent male and female friendship networks regarding smoking-based selection and influence processes using newly developed social network analysis methods that allow the current state of continuously changing friendship networks to act as a dynamic constraint for changes in smoking behaviour, while allowing current smoking behaviour to be simultaneously a dynamic constraint for changes in friendship networks.

DESIGN

Longitudinal design with four measurements.

SETTING

Nine junior high schools in Finland.

PARTICIPANTS

A total of 1163 adolescents (mean age = 13.6 years) who participated in the control group of the ESFA (European Smoking prevention Framework Approach) study, including 605 males and 558 females.

MEASUREMENTS

Smoking behaviour of adolescents, parents, siblings and friendship ties.

FINDINGS

Smoking-based selection of friends was found in male as well as female networks. However, support for influence among friends was found only in female networks. Furthermore, females and males were both influenced by parental smoking behaviour.

CONCLUSIONS

In Finnish adolescents, both male and female smokers tend to select other smokers as friends but it appears that only females are influenced to smoke by their peer group. This suggests that prevention campaigns targeting resisting peer pressure may be more effective in adolescent girls than boys.

Predicting the life-time benefit of school-based smoking prevention programmes

AIM

School-based smoking prevention programmes may delay the age of smoking initiation, but do not appear to achieve lasting reductions in smoking prevalence beyond school-leaving age. We explored whether delaying the age at which someone initiates smoking may have life-time benefits by increasing the likelihood of quitting in later life.

DESIGN AND SETTING

Data from the General Household Survey of Great Britain were used in a logistic regression model to examine the association between age at which someone initiates regular smoking and the probability that the person will quit smoking later in life. The effect of confounding variables (sex, ethnicity, socio-economic class, education and geographical location) was taken into account. The predicted relationship was used in a cohort model to estimate the life-time reduction in smoking prevalence and all-cause mortality of a school-based smoking prevention programme.

RESULTS

Age of regular smoking initiation was associated strongly with the probability of quitting later in life (coefficient -0.103, P < 0.001). The strength of the association was slightly reduced but still significant when confounding variables were included (coefficient -0.075, P < 0.001). An intervention that delays smoking initiation without decreasing smoking prevalence at age 18 may reduce adult smoking prevalence by 0.13-0.32% (depending on age) and all-cause mortality by 0.09% over the life-time of the sample.

CONCLUSION

School-based smoking prevention programmes have potential for a beneficial effect over the life-time of the participants even if they have no apparent effect at school-leaving age.

The structure of male adolescent peer networks and risk for intimate partner violence perpetration: findings from a national sample

Although peer networks have been implicated as influential in a range of adolescent behaviors, little is known about relationships between peer network structures and risk for intimate partner violence (IPV) among youth. This study is a descriptive analysis of how peer network "types" may be related to subsequent risk for IPV perpetration among adolescents using data from 3,030 male respondents to the National Longitudinal Study of Adolescent Health. Sampled youth were a mean of 16 years of age when surveyed about the nature of their peer networks, and 21.9 when asked to report about IPV perpetration in their adolescent and early adulthood relationships. A latent class analysis of the size, structure, gender composition and delinquency level of friendship groups identified four unique profiles of peer network structures. Men in the group type characterized by small, dense, mostly male peer networks with higher levels of delinquent behavior reported higher rates of subsequent IPV perpetration than men whose adolescent network type was characterized by large, loosely connected groups of less delinquent male and female friends. Other factors known to be antecedents and correlates of IPV perpetration varied in their distribution across the peer group types, suggesting that different configurations of risk for relationship aggression can be found across peer networks. Implications for prevention programming and future research are addressed.

'Acceptable rebellion': marketing hipster aesthetics to sell Camel cigarettes in the US

OBJECTIVE

The aim of the present work was to understand why and how RJ Reynolds and other tobacco companies have marketed tobacco products to young adult social trendsetting consumers (termed 'hipsters') to recruit trendsetters and average consumers to smoke.

METHODS

Analysis of tobacco industry documents and industry marketing materials.

RESULTS

Since 1995, RJ Reynolds developed its marketing campaigns to better suit the lifestyle, image identity and attitudes of hip trendsetters (so-called 'hipsters'), and Camel's brand identity actively shifted to more closely convey the hipster persona. Camel emphasised in-venue events such as promotional music tours to link the brand and smoking to activities and symbols appealing to hipsters and their emulating masses.

CONCLUSIONS

To reach this targeted and socially valuable trend-setting population, public health advocates must tap into hipster psychology and expose to the targeted community the tobacco company's efforts to infiltrate the hipster community to turn hipsters into tobacco-using role models.

Community participation for malaria elimination in Tafea Province, Vanuatu: Part I. Maintaining motivation for prevention practices in the context of disappearing disease

Background

In the 1990s, the experience of eliminating malaria from Aneityum Island, Vanuatu is often given as evidence for the potential to eliminate malaria in the south-west Pacific. This experience, however, cannot provide a blueprint for larger islands that represent more complex social and environmental contexts. Community support was a key contributor to success in Aneityum. In the context of disappearing disease, obtaining and maintaining community participation in strategies to eliminate malaria in the rest of Tafea Province, Vanuatu will be significantly more challenging.

Method

Nine focus group discussions (FGDs), 12 key informant interviews (KIIs), three transect walks and seven participatory workshops were carried out in three villages across Tanna Island to investigate community perceptions and practices relating to malaria prevention (particularly relating to bed nets); influences on these practices including how malaria is contextualized within community health and disease priorities; and effective avenues for channelling health information.

Results

The primary protection method identified by participants was the use of bed nets, however, the frequency and motivation for their use differed between study villages on the basis of the perceived presence of malaria. Village, household and personal cleanliness were identified by participants as important for protection against malaria. Barriers and influences on bed net use included cultural beliefs and practices, travel, gender roles, seasonality of mosquito nuisance and risk perception. Health care workers and church leaders were reported to have greatest influence on malaria prevention practices. Participants preferred receiving health information through visiting community health promotion teams, health workers, church leaders and village chiefs.

Conclusion

In low malaria transmission settings, a package for augmenting social capital and sustaining community participation for elimination will be essential and includes: 'sentinel sites' for qualitative monitoring of evolving local socio-cultural, behavioural and practical issues that impact malaria prevention and treatment; mobilizing social networks; intersectoral collaboration; integration of malaria interventions with activities addressing other community health and disease priorities; and targeted implementation of locally appropriate, multi-level, media campaigns that sustain motivation for community participation in malaria elimination.

The effectiveness of a school-based substance abuse prevention program: 18-month follow-up of the EU-Dap cluster randomized controlled trial

AIM

To evaluate the effectiveness of a school-based substance abuse prevention program developed in the EU-Dap study (EUropean Drug Addiction Prevention trial).

MATERIALS AND METHODS

Cluster Randomized Controlled Trial. Seven European countries participated in the study; 170 schools (7079 pupils 12-14 years of age) were randomly assigned to one of three experimental conditions or to a control condition during the school year 2004/2005. The program consisted of a 12-h curriculum based on a comprehensive social influence approach. A pre-test survey assessing past and current substance use was conducted before the implementation of the program, while a post-test survey was carried out about 18 months after the pre-test. The association between program condition and change in substance use at post-test was expressed as adjusted prevalence odds ratio (POR), estimated by multilevel regression models.

RESULTS

Persisting beneficial program effects were found for episodes of drunkenness (any, POR=0.80; 0.67-0.97; frequent, POR=0.62; 0.47-0.81) and for frequent cannabis use in the past 30 days (POR=0.74; 0.53-1.00), whereas daily cigarette smoking was not affected by the program as it was at the short-term follow-up. Baseline non-smokers that participated in the program progressed in tobacco consumption to a lower extent than those in the control condition, but no difference was detected in the proportion of quitters or reducers among baseline daily smokers.

CONCLUSION

The experimental evaluation of an innovative school curriculum based on a comprehensive social influence approach, indicated persistent positive effects over 18 months for alcohol abuse and for cannabis use, but not for cigarette smoking.

A participatory parent-focused intervention promoting physical activity in preschools: design of a cluster-randomized trial

Background

With rates of childhood obesity increasing, physical activity (PA) promotion especially in young children has assumed greater importance. Given the limited effectiveness of most interventions to date, new approaches are needed. The General Systems theory suggests that involving parents as intervention targets may be effective in fostering healthier life styles in children. We describe the development of a parent-focused participatory intervention and the procedures used to evaluate its effectiveness in increasing daily PA in preschoolers.

Methods/Design

Thirty-seven South German preschools were identified for this study and agreed to participate. Using a two-armed, controlled cluster-randomized trial design we test a participatory intervention with parents as the primary target group and potential agents of behavioural change. Specifically, the intervention is designed to engage parents in the development, refinement and selection of project ideas to promote PA and in incorporating these ideas into daily routines within the preschool community, consisting of children, teachers and parents. Our study is embedded within an existing state-sponsored programme providing structured gym lessons to preschool children. Thus, child-based PA outcomes from the study arm with the parent-focused intervention and the state-sponsored programme are compared with those from the study arm with the state-sponsored programme alone. The evaluation entails baseline measurements of study outcomes as well as follow-up measurements at 6 and 12 months. Accelerometry measures PA intensity over a period of six days, with the mean over six days used as the primary outcome measure. Secondary outcomes include childrens' BMI, a sum of averaged skin fold thickness measurements across multiple sites, and PA behaviour. Longitudinal multilevel models are used to assess within-subject change and between-group differences in study outcomes, adjusted for covariates at the preschool and individual levels. Teacher qualitative interviews monitor the intervention implementation process.

Discussion

Participatory approaches that actively involve parents have the potential to promote PA in ways that might be better tailored to local needs and more sustainable. Our mixed methods approach to assess the intervention efficacy and implementation employing both quantitative and qualitative measures within a cluster-randomized controlled trial may serve as a framework for evaluating public health interventions in preschool settings.

Trial Registration

clinicaltrials.gov No: NCT00987532

Licence to be active: parental concerns and 10-11-year-old children's ability to be independently physically active

BACKGROUND

Physical activity independent of adult supervision is an important component of youth physical activity. This study examined parental attitudes to independent activity, factors that limit licence to be independently active and parental strategies to facilitate independent activity.

METHODS

In-depth phone interviews were conducted with 24 parents (4 males) of 10-11-year-old children recruited from six primary schools in Bristol.

RESULTS

Parents perceived that a lack of appropriate spaces in which to be active, safety, traffic, the proximity of friends and older children affected children's ability to be independently physically active. The final year of primary school was perceived as a period when children should be afforded increased licence. Parents managed physical activity licence by placing time limits on activity, restricting activity to close to home, only allowing activity in groups or under adult supervision.

CONCLUSIONS

Strategies are needed to build children's licence to be independently active; this could be achieved by developing parental self-efficacy to allow children to be active and developing structures such as safe routes to parks and safer play areas. Future programmes could make use of traffic-calming programmes as catalysts for safe independent physical activity.

Identifying influential young people to undertake effective peer-led health promotion: the example of A Stop Smoking In Schools Trial (ASSIST)

The objective of the study was to develop and evaluate an effective whole-community approach to identifying a diverse group of influential young people to effectively diffuse health promotion messages among their peers. A peer nomination questionnaire, developed through extensive piloting work, was completed by 10 730 Year 8 students (aged 12-13 years) in 59 schools (30 intervention, 29 control) as part of a cluster randomized controlled trial. Influential students identified in 30 intervention schools were trained to disseminate smoke-free health promotion messages through informal contacts with peers. This approach successfully identified, recruited and retained a diverse group of students, broadly representative of their year group, to undertake the role of 'peer supporter'. Although students and staff expressed doubts about the suitability of some young people recruited as peer supporters, the intervention achieved a 22% reduction in the odds of being a regular smoker in intervention compared with control schools [odds ratio 0.78 (95% CI 0.64-0.96)]. Carefully designed and developed peer-led interventions have potential for delivering effective smoking prevention among adolescents. Paying close attention to the way in which peer educators are identified, and involving young people themselves in this process, may be the key to increasing the effectiveness of peer education.

If cannabis caused schizophrenia--how many cannabis users may need to be prevented in order to prevent one case of schizophrenia? England and Wales calculations

BACKGROUND

We consider how many cannabis users may need to be prevented in order to prevent one case of schizophrenia or psychosis [defined as number needed to prevent (NNP)].

METHOD

Calculation for England and Wales using best available estimates of: incidence of schizophrenia; rates of heavy and light cannabis use; and risk that cannabis causes schizophrenia.

RESULTS

In men the annual mean NNP for heavy cannabis and schizophrenia ranged from 2800 [90% confidence interval (CI) 2018-4530] in those aged 20-24 years to 4700 (90% CI 3114-8416) in those aged 35-39. In women, mean NNP for heavy cannabis use and schizophrenia ranged from 5470 (90% CI 3640-9839) in those aged 25-29 to 10 870 (90% CI 6786-22 732) in 35-39-year-olds. Equivalent mean NNP for heavy cannabis use and psychosis were lower, from 1360 (90% CI 1007-2124) in men aged 20-24 and 2480 (90% CI 1408-3518) in women aged 16-19. The mean and median number of light cannabis users that would need to be prevented in order to prevent one case of schizophrenia or psychosis per year are four to five times greater than among heavy users.

CONCLUSIONS

The number of young people who need to be exposed to an intervention to generate NNP and prevent one case of schizophrenia will be even larger. The public health importance of preventing cannabis to reduce schizophrenia or psychosis remains uncertain. More attention should be given to testing the hypothesis that cannabis is related causally to psychotic outcomes, and to considering what strategies will be the most effective in reducing heavy cannabis use among young people.

Dynamics of adolescent friendship networks and smoking behavior: social network analyses in six European countries

The co-evolution of adolescents' friendship networks and their smoking behavior is examined in a large sample across six European countries. Selection and influence processes are disentangled using new methods of social network analysis that enable alternative selection mechanisms to be controlled for. The sample consisted of 7704 adolescents participating in the control group of the ESFA (European Smoking prevention Framework Approach) study. The design was longitudinal with four observations. The main measurements were friendship ties, adolescents smoking behavior, parental smoking behavior, and sibling smoking behavior. Results indicated that in each country adolescents preferred selecting friends based on similar smoking behavior. Support for the influence of friends was found in only two countries. A similarity in smoking behavior between friends was explained more strongly by smoking-based selection processes than by the influence of friends in each of the six countries. Prevention programs need to address aspects that drive peer selection, and reinforce non-smoking attitudes in adolescents.

Relative risks of exposure to different smoking models on the development of nicotine dependence during adolescence: a five-wave longitudinal study

PURPOSE

Many studies have focused upon predictors of smoking onset and continuation in adolescents. However, less is known about the development of nicotine dependence (ND) and how smoking in the interpersonal environment relates to this. To examine which smoking models have the largest impact on the development of ND, we examined the relative impact of current smoking from fathers, mothers, siblings, best friends, and friend groups on the development of ND in adolescents.

METHODS

Data were used from five annual waves of the "Family and Health" survey project. At baseline 428 adolescents (mean age=15.2 years; SD=.60), both their parents, and their siblings were participating. In this study we included only smoking adolescents (n=175). To assess the individual development of ND of each adolescent, and whether current smoking exposure affected changes from baseline across time, we used latent growth curve modeling (LGC).

RESULTS

Findings revealed that smoking of sibling and best friend were related to baseline levels of ND, but not to the rates of change over time. Of all models, only having smoking friends in the friend group was related to a faster development of ND.

CONCLUSIONS

The current findings highlight the key role of smoking friends in the development of ND and suggest that interventions targeting at peers are probably effective in reducing the prevalence of ND symptoms among adolescents.

Educating youth about health and science using a partnership between an academic medical center and community-based science museum

Declining student interest and scholastic abilities in the sciences are concerns for the health professions. Additionally, the National Institutes of Health is committed to promoting more research on health behaviors among US youth, where one of the most striking contemporary issues is obesity. This paper reports findings on the impact of a partnership between Oregon Health and Science University (OHSU) and the Oregon Museum of Science and Industry linked to a 17-week exhibition of BodyWorlds3 and designed to inform rural underserved youth about science and health research. Self-administered survey measures included health knowledge, attitudes, intended health behaviors, and interest in the health professions. Four hundred four surveys (88% of participants) were included in analyses. Ninety percent or more found both the BodyWorlds (n = 404) and OHSU (n = 239) exhibits interesting. Dental care habits showed the highest level of intended behavior change (Dental = 45%, Exercise = 34%, Eating = 30%). Overall, females and middle school students were more likely than male and high school students, respectively, to state an intention to change exercise, eating and dental care habits. Females and high school students were more likely to have considered a career in health or science prior to their exhibit visit and, following the exhibit, were more likely to report that this intention had been reinforced. About 6% of those who had not previously considered a career in health or science (n = 225) reported being more likely to do so after viewing the exhibits. In conclusion, high quality experiential learning best created by community-academic partnerships appears to have the ability to stimulate interest and influence intentions to change health behaviors among middle and high school students.

Solar drinking water disinfection (SODIS) to reduce childhood diarrhoea in rural Bolivia: a cluster-randomized, controlled trial

BACKGROUND

Solar drinking water disinfection (SODIS) is a low-cost, point-of-use water purification method that has been disseminated globally. Laboratory studies suggest that SODIS is highly efficacious in inactivating waterborne pathogens. Previous field studies provided limited evidence for its effectiveness in reducing diarrhoea.

METHODS AND FINDINGS

We conducted a cluster-randomized controlled trial in 22 rural communities in Bolivia to evaluate the effect of SODIS in reducing diarrhoea among children under the age of 5 y. A local nongovernmental organisation conducted a standardised interactive SODIS-promotion campaign in 11 communities targeting households, communities, and primary schools. Mothers completed a daily child health diary for 1 y. Within the intervention arm 225 households (376 children) were trained to expose water-filled polyethyleneteraphtalate bottles to sunlight. Eleven communities (200 households, 349 children) served as a control. We recorded 166,971 person-days of observation during the trial representing 79.9% and 78.9% of the total possible person-days of child observation in intervention and control arms, respectively. Mean compliance with SODIS was 32.1%. The reported incidence rate of gastrointestinal illness in children in the intervention arm was 3.6 compared to 4.3 episodes/year at risk in the control arm. The relative rate of diarrhoea adjusted for intracluster correlation was 0.81 (95% confidence interval 0.59-1.12). The median length of diarrhoea was 3 d in both groups.

CONCLUSIONS

Despite an extensive SODIS promotion campaign we found only moderate compliance with the intervention and no strong evidence for a substantive reduction in diarrhoea among children. These results suggest that there is a need for better evidence of how the well-established laboratory efficacy of this home-based water treatment method translates into field effectiveness under various cultural settings and intervention intensities. Further global promotion of SODIS for general use should be undertaken with care until such evidence is available.

TRIAL REGISTRATION

www.ClinicalTrials.govNCT00731497 Please see later in the article for Editors' Summary.

Theorising interventions as events in systems

Conventional thinking about preventive interventions focuses over simplistically on the "package" of activities and/or their educational messages. An alternative is to focus on the dynamic properties of the context into which the intervention is introduced. Schools, communities and worksites can be thought of as complex ecological systems. They can be theorised on three dimensions: (1) their constituent activity settings (e.g., clubs, festivals, assemblies, classrooms); (2) the social networks that connect the people and the settings; and (3) time. An intervention may then be seen as a critical event in the history of a system, leading to the evolution of new structures of interaction and new shared meanings. Interventions impact on evolving networks of person-time-place interaction, changing relationships, displacing existing activities and redistributing and transforming resources. This alternative view has significant implications for how interventions should be evaluated and how they could be made more effective. We explore this idea, drawing on social network analysis and complex systems theory.

Preventing bias in cluster randomised trials

Bruno Giraudeau and Philippe Ravaud discuss the difficulties in preventing selection bias and applying intention-to-treat analysis in cluster randomized trials, and propose some solutions.

Prevalence and risk factors for initiation of smoking in Greek high-school students

The smoking habits of 9,276 high-school students (15-18 years old) in six cities of Northern Greece were studied using a questionnaire in order to determine the prevalence and possible risk factors for initiation of smoking. We observed that 29.6% of high-school students (32.6% of boys and 26.7% of girls) were current smokers. A percentage of 43.3% had started smoking before the age of 14. Reactive behaviour towards parents' and teachers' advice (40.2%) and the existence of smoking friends (40.1%) were the main reasons of initiation. A well-planned integrated anti-smoking campaign is urgently required, especially among students and teachers.

Parental drug use, early adversities, later childhood problems and children's use of tobacco and alcohol at age 10: birth cohort study

AIMS

To estimate the prevalence of alcohol and tobacco use among children at age 10 years and to investigate possible influences on this.

DESIGN

Birth cohort study.

SETTING

England.

PARTICIPANTS

A total of 6895 children provided data at age 10.

MEASUREMENTS

Parental tobacco, alcohol and cannabis use, parental social position, children's intelligence, behavioural and emotional problems, children's tobacco and alcohol use at age 10.

FINDINGS

A total of 1.3% of children reported smoking and 1.8% reported drinking alcohol, with boys reporting higher use than girls. Parental social disadvantage was the strongest predictor of children's smoking and also predicted children's alcohol use. Some of this association appeared to be mediated through the greater experience of childhood behavioural and cognitive problems among the disadvantaged. Parental smoking and paternal alcohol use had little independent influence on offspring drug use. Postnatal, rather than prenatal, maternal alcohol use predicted children's alcohol use.

CONCLUSIONS

Strategies to prevent early initiation of tobacco and alcohol use should focus upon the reduction of childhood social disadvantage and the behavioural and cognitive problems associated with this.