Objective To quantify the effect of opiate substitution treatment in relation to HIV transmission among people who inject drugs. Design Systematic review and meta-analysis of prospective published and unpublished observational studies. Data sources Search of Medline, Embase, PsychINFO, and the Cochrane Library from the earliest year to 2011 without language restriction. Review methods We selected studies that directly assessed the impact of opiate substitution treatment in relation to incidence of HIV and studies that assessed incidence of HIV in people who inject drugs and that might have collected data regarding exposure to opiate substitution treatment but not have reported it. Authors of these studies were contacted. Data were extracted by two reviewers and pooled in a meta-analysis with a random effects model. Results Twelve published studies that examined the impact of opiate substitution treatment on HIV transmission met criteria for inclusion, and unpublished data were obtained from three additional studies. All included studies examined methadone maintenance treatment. Data from nine of these studies could be pooled, including 819 incident HIV infections over 23 608 person years of follow-up. Opiate substitution treatment was associated with a 54% reduction in risk of HIV infection among people who inject drugs (rate ratio 0.46, 95% confidence interval 0.32 to 0.67; P<0.001). There was evidence of heterogeneity between studies (I²=60%, χ²=20.12, P=0.010), which could not be explained by geographical region, site of recruitment, or the provision of incentives. There was weak evidence for greater benefit associated with longer duration of exposure to opiate substitution treatment. Conclusion Opiate substitution treatment provided as maintenance therapy is associated with a reduction in the risk of HIV infection among people who inject drugs. These findings, however, could reflect comparatively high levels of motivation to change behaviour and reduce injecting risk behaviour among people who inject drugs who are receiving opiate substitution treatment.

Background and Aims: Peer‐led interventions may offer a beneficial approach in preventing substance use, but their impact has not yet been quantified. We conducted a systematic review to investigate and quantify the effect of peer‐led interventions that sought to prevent tobacco, alcohol and/or drug use among young people aged 11–21 years.Methods: Medline, EMBASE, PsycINFO, CINAHL, ERIC and the Cochrane Library were searched from inception to July 2015 without language restriction. We included randomized controlled trials only. Screening and data extraction were conducted in duplicate and data from eligible studies were pooled in a random effects meta‐analysis.Results: We identified 17 eligible studies, approximately half of which were school‐based studies targeting tobacco use among adolescents. Ten studies targeting tobacco use could be pooled, representing 13 706 young people in 220 schools. Meta‐analysis demonstrated that the odds of smoking were lower among those receiving the peer‐led intervention compared with control [odds ratio (OR) = 0.78, 95% confidence interval (CI) = 0.62–0.99, P = 0.040]. There was evidence of heterogeneity (I² = 41%, χ² 15.17, P = 0.086). Pooling of six studies representing 1699 individuals in 66 schools demonstrated that peer‐led interventions were also associated with benefit in relation to alcohol use (OR = 0.80, 95% CI = 0.65–0.99, P = 0.036), while three studies (n = 976 students in 38 schools) suggested an association with lower odds of cannabis use (OR = 0.70, 0.50–0.97, P = 0.034). No studies were found that targeted other illicit drug use.Conclusions: Peer interventions may be effective in preventing tobacco, alcohol and possibly cannabis use among adolescents, although the evidence base is limited overall, and is characterized mainly by small studies of low quality.

Adolescent risk behaviours such as smoking, alcohol use and antisocial behaviour are associated with increased risk of morbidity and mortality. Patterns of risk behaviour may vary between genders during adolescence. Analysis of data from a longitudinal birth cohort to assess the prevalence and distribution of multiple risk behaviours by gender at age 15–16 years with a focus on alcohol use at age 10, 13 and 15 years. By age 15 years, over half of boys and girls had consumed alcohol and one-fifth had engaged in binge drinking with no clear difference by gender. At age 15–16 years, the most prevalent risk behaviours were physical inactivity (74%), antisocial and criminal behaviour (42%) and hazardous drinking (34%). Boys and girls engaged in a similar number of behaviours but antisocial and criminal behaviours, cannabis use and vehicle-related risk behaviours were more prevalent among boys, whilst tobacco smoking, self-harm and physical inactivity were more prevalent among girls. Multiple risk behaviour is prevalent in both genders during adolescence but the pattern of individual risk behaviour varies between boys and girls. Effective interventions at the individual, family, school, community or population level are needed to address gender-specific patterns of risk behaviour during adolescence.

Background Engagement in multiple risk behaviours can have adverse consequences for health during childhood, during adolescence, and later in life, yet little is known about the impact of different types of interventions that target multiple risk behaviours in children and young people, or the differential impact of universal versus targeted approaches. Findings from systematic reviews have been mixed, and effects of these interventions have not been quantitatively estimated. Objectives To examine the effects of interventions implemented up to 18 years of age for the primary or secondary prevention of multiple risk behaviours among young people. Search methods We searched 11 databases (Australian Education Index; British Education Index; Campbell Library; Cumulative Index to Nursing and Allied Health Literature (CINAHL); Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; Embase; Education Resource Information Center (ERIC); International Bibliography of the Social Sciences; MEDLINE; PsycINFO; and Sociological Abstracts) on three occasions (2012, 2015, and 14 November 2016)). We conducted handsearches of reference lists, contacted experts in the field, conducted citation searches, and searched websites of relevant organisations. Selection criteria We included randomised controlled trials (RCTs), including cluster RCTs, which aimed to address at least two risk behaviours. Participants were children and young people up to 18 years of age and/or parents, guardians, or carers, as long as the intervention aimed to address involvement in multiple risk behaviours among children and young people up to 18 years of age. However, studies could include outcome data on children > 18 years of age at the time of follow‐up. Specifically,we included studies with outcomes collected from those eight to 25 years of age. Further, we included only studies with a combined intervention and follow‐up period of six months or longer. We excluded interventions aimed at individuals with clinically diagnosed disorders along with clinical interventions. We categorised interventions according to whether they were conducted at the individual level; the family level; or the school level. Data collection and analysis We identified a total of 34,680 titles, screened 27,691 articles and assessed 424 full‐text articles for eligibility. Two or more review authors independently assessed studies for inclusion in the review, extracted data, and assessed risk of bias. We pooled data in meta‐analyses using a random‐effects (DerSimonian and Laird) model in RevMan 5.3. For each outcome, we included subgroups related to study type (individual, family, or school level, and universal or targeted approach) and examined effectiveness at up to 12 months' follow‐up and over the longer term (> 12 months). We assessed the quality and certainty of evidence using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. Main results We included in the review a total of 70 eligible studies, of which a substantial proportion were universal school‐based studies (n = 28; 40%). Most studies were conducted in the USA (n = 55; 79%). On average, studies aimed to prevent four of the primary behaviours. Behaviours that were most frequently addressed included alcohol use (n = 55), drug use (n = 53), and/or antisocial behaviour (n = 53), followed by tobacco use (n = 42). No studies aimed to prevent self‐harm or gambling alongside other behaviours. Evidence suggests that for multiple risk behaviours, universal school‐based interventions were beneficial in relation to tobacco use (odds ratio (OR) 0.77, 95% confidence interval (CI) 0.60 to 0.97; n = 9 studies; 15,354 participants) and alcohol use (OR 0.72, 95% CI 0.56 to 0.92; n = 8 studies; 8751 participants; both moderate‐quality evidence) compared to a comparator, and that such interventions may be effective in preventing illicit drug use (OR 0.74, 95% CI 0.55 to 1.00; n = 5 studies; 11,058 participants; low‐quality evidence) and engagement in any antisocial behaviour (OR 0.81, 95% CI 0.66 to 0.98; n = 13 studies; 20,756 participants; very low‐quality evidence) at up to 12 months' follow‐up, although there was evidence of moderate to substantial heterogeneity (I² = 49% to 69%). Moderate‐quality evidence also showed that multiple risk behaviour universal school‐based interventions improved the odds of physical activity (OR 1.32, 95% CI 1.16 to 1.50; I² = 0%; n = 4 studies; 6441 participants). We considered observed effects to be of public health importance when applied at the population level. Evidence was less certain for the effects of such multiple risk behaviour interventions for cannabis use (OR 0.79, 95% CI 0.62 to 1.01; P = 0.06; n = 5 studies; 4140 participants; I² = 0%; moderate‐quality evidence), sexual risk behaviours (OR 0.83, 95% CI 0.61 to 1.12; P = 0.22; n = 6 studies; 12,633 participants; I² = 77%; low‐quality evidence), and unhealthy diet (OR 0.82, 95% CI 0.64 to 1.06; P = 0.13; n = 3 studies; 6441 participants; I² = 49%; moderate‐quality evidence). It is important to note that some evidence supported the positive effects of universal school‐level interventions on three or more risk behaviours. For most outcomes of individual‐ and family‐level targeted and universal interventions, moderate‐ or low‐quality evidence suggests little or no effect, although caution is warranted in interpretation because few of these studies were available for comparison (n ≤ 4 studies for each outcome). Seven studies reported adverse effects, which involved evidence suggestive of increased involvement in a risk behaviour among participants receiving the intervention compared to participants given control interventions. We judged the quality of evidence to be moderate or low...

Drinking is viewed by young people as a predominantly social activity which provides an opportunity for entertainment and bonding with friends. Using Bourdieu's concepts of habitus, field and capital, this article explores young people's attitudes and beliefs around alcohol use, influences on behaviour, and the role of peers, with a view to informing the development of preventive interventions. Semi‐structured interviews were conducted with 28 young people aged 18–20 in the south west of England. We describe how friends were integral in drinking experiences, and drinking with friends was equated with fun and enjoyment. In this way, the desire for social and symbolic capital appeared to be a key motivator for adolescent drinking. Critically, however, wider cultural norms played the predominant role in shaping behaviour, via the internalisation of widely accepted practice and the subsequent externalisation of norms through the habitus. Applying Bourdieu's theory suggests that population‐level interventions that regulate alcohol consumption, and thus disrupt the field, are likely to facilitate behaviour change among young people by driving a response in habitus.