Injecting drug use and hepatitis C virus infection independently increase biomarkers of inflammatory disease risk which are incompletely restored by curative direct-acting antiviral therapy.

Background: Hepatitis C virus (HCV) infections are more prevalent in people who inject drugs (PWID) who often experience additional health risks. HCV induces inflammation and immune alterations that contribute to hepatic and non-hepatic morbidities. It remains unclear whether curative direct acting antiviral (DAA) therapy completely reverses immune alterations in PWID. Methods: Plasma biomarkers of immune activation associated with chronic disease risk were measured in HCV-seronegative (n=24) and HCV RNA+ (n=32) PWID at baseline and longitudinally after DAA therapy. Adjusted generalised estimating equations were used to assess longitudinal changes in biomarker levels. Comparisons between community controls (n=29) and HCV-seronegative PWID were made using adjusted multiple regression modelling. Results: HCV-seronegative PWID exhibited significantly increased levels of inflammatory biomarkers including soluble (s) TNF-RII, IL-6, sCD14 and sCD163 and the diabetes index HbA1c as compared to community controls. CXCL10, sTNF-RII, vascular cell adhesion molecule-1 and lipopolysaccharide binding protein (LBP) were additionally elevated in PWID with viremic HCV infection as compared to HCV- PWID. Whilst curative DAA therapy reversed some biomarkers, others including LBP and sTNF-RII remained elevated 48 weeks after HCV cure. Conclusion: Elevated levels of inflammatory and chronic disease biomarkers in PWID suggest an increased risk of chronic morbidities such as diabetes and cardiovascular disease. HCV infection in PWID poses an additional disease burden, amplified by the incomplete reversal of immune dysfunction following DAA therapy. These findings highlight the need for heightened clinical surveillance of PWID for chronic inflammatory diseases, particularly those with a history of HCV infection.

Approaches and reporting of alcohol and other drug testing for injured patients in hospital-based studies: A systematic review.

ISSUE: Hospital alcohol and/or other drug (AOD) testing is important for identifying AOD-related injuries; however, testing methods vary. This systematic review aimed to examine biological AOD testing methods from hospital-based studies of injured patients and quantify what proportion reported key information on those testing methods. APPROACH: Observational studies published in English from 2010 onwards involving biological AOD testing for injured patients presenting to hospital were included. Studies examining single injury causes were excluded. Extracted data included concentration thresholds for AOD detection (e.g., lower limits of detection, author-defined cut-offs), test type (e.g., immunoassay, breathalyser) and approach (e.g., routine, clinical discretion), timing of testing, sample type and the proportion of injured cases tested for AODs. KEY FINDINGS: Of 83 included studies, 76 measured alcohol and 37 other drugs. Forty-nine studies defined blood alcohol concentration thresholds (ranging from 0 to 0.1 g/100 mL). Seven studies defined concentration thresholds for other drugs. Testing approach was reported in 39/76 alcohol and 18/37 other drug studies. Sample type was commonly reported (alcohol: n = 69/76; other drugs: n = 28/37); alcohol was typically measured using blood (n = 60) and other drugs using urine (n = 20). Studies that reported the proportion of cases tested (alcohol: n = 53/76; other drugs: n = 28/37), reported that between 0% and 89% of cases were not tested for alcohol and 0% and 91% for other drugs. Timing of testing was often unreported (alcohol: n = 61; other drugs: n = 30). IMPLICATIONS AND CONCLUSION: Variation in AOD testing methods alongside incomplete reporting of those methods limits data comparability and interpretation. Standardised reporting of testing methods will assist AOD-related injury surveillance and prevention.

Prevalence of alcohol and other drug detections in non-transport injury events.

OBJECTIVE: To measure the prevalence of alcohol and/or other drug (AOD) detections in suspected major trauma patients with non-transport injuries who presented to an adult major trauma centre. METHODS: This registry-based cohort study examined the prevalence of AOD detections in patients aged ≥18 years who: (i) sustained non-transport injuries; and (ii) met predefined trauma call-out criteria and were therefore managed by an interdisciplinary trauma team between 1 July 2021 and 31 December 2022. Prevalence was measured using routine in-hospital blood alcohol and urine drug screens. RESULTS: A total of 1469 cases met the inclusion criteria. Of cases with a valid blood test (n = 1248, 85.0%), alcohol was detected in 313 (25.1%) patients. Of the 733 (49.9%) cases with urine drug screen results, cannabinoids were most commonly detected (n = 103, 14.1%), followed by benzodiazepines (n = 98, 13.4%), amphetamine-type substances (n = 80, 10.9%), opioids (n = 28, 3.8%) and cocaine (n = 17, 2.3%). Alcohol and/or at least one other drug was detected in 37.4% (n = 472) of cases with either a blood alcohol or urine drug test completed (n = 1263, 86.0%). Multiple substances were detected in 16.6% (n = 119) of cases with both blood alcohol and urine drug screens (n = 718, 48.9%). Detections were prevalent in cases of interpersonal violence (n = 123/179, 68.7%) and intentional self-harm (n = 50/106, 47.2%), and in those occurring on Friday and Saturday nights (n = 118/191, 61.8%). CONCLUSION: AOD detections were common in trauma patients with non-transport injury causes. Population-level surveillance is needed to inform prevention strategies that address AOD use as a significant risk factor for serious injury.

Prevalence of Alcohol and Other Drug Use in Patients Presenting to Hospital for Violence-Related Injuries: A Systematic Review.

Substance use is a risk factor for being both a perpetrator and a victim of violence. The aim of this systematic review was to report the prevalence of acute pre-injury substance use in patients with violence-related injuries. Systematic searches were used to identify observational studies that included patients aged ≥15 years presenting to hospital after violence-related injuries and used objective toxicology measures to report prevalence of acute pre-injury substance use. Studies were grouped based on injury cause (any violence-related, assault, firearm, and other penetrating injuries including stab and incised wounds) and substance type (any substance, alcohol only, drugs other than alcohol only), and they were summarized using narrative synthesis and meta-analyses. This review included 28 studies. Alcohol was detected in 13%-66% of any violence-related injuries (five studies), 4%-71% of assaults (13 studies), 21%-45% of firearm injuries (six studies; pooled estimate = 41%, 95% CI: 40%-42%, n = 9,190), and 9%-66% of other penetrating injuries (nine studies; pooled estimate = 60%, 95% CI: 56%-64%, n = 6,950). Drugs other than alcohol were detected in 37% of any violence-related injuries (one study), 39% of firearm injuries (one study), 7%-49% of assaults (five studies), and 5%-66% of penetrating injuries (three studies). The prevalence of any substance varied across injury categories: any violence-related injuries = 76%-77% (three studies), assaults = 40%-73% (six studies), firearms = n/a, other penetrating injuries = 26%-45% (four studies; pooled estimate = 30%, 95% CI: 24%-37%, n = 319).Overall, substance use was frequently detected in patients presenting to hospital for violence-related injuries. Quantification of substance use in violence-related injuries provides a benchmark for harm reduction and injury prevention strategies.

Prevalence and incidence of emergency department presentations and hospital separations with injecting-related infections in a longitudinal cohort of people who inject drugs.

People who inject drugs are at risk of acute bacterial and fungal injecting-related infections. There is evidence that incidence of hospitalizations for injecting-related infections are increasing in several countries, but little is known at an individual level. We aimed to examine injecting-related infections in a linked longitudinal cohort of people who inject drugs in Melbourne, Australia. A retrospective descriptive analysis was conducted to estimate the prevalence and incidence of injecting-related infections using administrative emergency department and hospital separation datasets linked to the SuperMIX cohort, from 2008 to 2018. Over the study period, 33% (95%CI: 31-36%) of participants presented to emergency department with any injecting-related infections and 27% (95%CI: 25-30%) were admitted to hospital. Of 1,044 emergency department presentations and 740 hospital separations, skin and soft tissue infections were most common, 88% and 76%, respectively. From 2008 to 2018, there was a substantial increase in emergency department presentations and hospital separations with any injecting-related infections, 48 to 135 per 1,000 person-years, and 18 to 102 per 1,000 person-years, respectively. The results emphasize that injecting-related infections are increasing, and that new models of care are needed to help prevent and facilitate early detection of superficial infection to avoid potentially life-threatening severe infections.

Identifying the Most Effective Recruitment Strategy Using Financial Reimbursements for a Web-Based Peer Network Study With Young People Aged 16-18 Years: Protocol for a Randomized Controlled Trial.

BACKGROUND: Peers are an important determinant of health and well-being during late adolescence; however, there is limited quantitative research examining peer influence. Previous peer network research with adolescents faced methodological limitations and difficulties recruiting young people. OBJECTIVE: This study aims to determine whether a web-based peer network survey is effective at recruiting adolescent peer networks by comparing 2 strategies for reimbursement. METHODS: This study will use a 2-group randomized trial design to test the effectiveness of reimbursements for peer referral in a web-based cross-sectional peer network survey. Young people aged 16-18 years recruited through Instagram, Snapchat, and a survey panel will be randomized to receive either scaled group reimbursement (the experimental group) or fixed individual reimbursement (the control group). All participants will receive a reimbursement of Aus $5 (US $3.70) for their own survey completion. In the experimental group (scaled group reimbursement), all participants within a peer network will receive an additional Aus $5 (US $3.70) voucher for each referred participant who completes the study, up to a maximum total value of Aus $30 (US $22.20) per participant. In the control group (fixed individual reimbursement), participants will only be reimbursed for their own survey completion. Participants' peer networks are assessed during the survey by asking about their close friends. A unique survey link will be generated to share with the participant's nominated friends for the recruitment of secondary participants. Outcomes are the proportion of a participant's peer network and the number of referred peers who complete the survey. The required sample size is 306 primary participants. Using a multilevel logistic regression model, we will assess the effect of the reimbursement intervention on the proportion of primary participants' close friends who complete the survey. The secondary aim is to determine participant characteristics that are associated with successfully recruiting close friends. Young people aged 16-18 years were involved in the development of the study design through focus groups and interviews (n=26). RESULTS: Participant recruitment commenced in 2022. CONCLUSIONS: A longitudinal web-based social network study could provide important data on how social networks and their influence change over time. This trial aims to determine whether scaled group reimbursement can increase the number of peers referred. The outcomes of this trial will improve the recruitment of young people to web-based network studies of sensitive health issues. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/44813.

Time-to-hepatitis C treatment initiation among people who inject drugs in Melbourne, Australia.

This study aims to understand the time-to-treatment initiation pre and post DAA access to inform strategies to improve HCV care. The data for our study were derived from the SuperMIX cohort study of people who inject drugs in Melbourne, Australia. Time-to-event analysis using Weibull accelerated failure time was performed for data collected between 2009 and 2021, among a cohort of HCV-positive participants. Among 223 participants who tested positive for active hepatitis C infection, 102 people (45.7%) reported treatment initiation, with a median time-to-treatment of 7 years. However, the median time-to-treatment reduced to 2.3 years for those tested positive after 2016. The study found that treatment with Opioid Agonist Therapy (TR 0.7, 95% CI 0.6-0.9), engagement with health or social services (TR 0.7, 95% CI 0.6-0.9), and having a first positive HCV RNA test after March 2016 (TR 0.3, 95% CI 0.2-0.3) were associated with a reduced time-to-treatment initiation. The study highlights the need for strategies to improve engagement with health services, including drug treatment services into routine HCV care to achieve timely treatment.

COVID-19 vaccine attitudes and facilitators among people in Australia who inject drugs.

INTRODUCTION: We aimed to describe COVID-19 vaccination attitudes and identify potential facilitators for vaccine uptake among people who inject drugs. METHODS: People who inject drugs were recruited from all eight Australian capital cities (N = 884; 65% male, mean age 44 years) and interviewed face-to-face or via telephone in June-July 2021. COVID-19 and broader vaccination attitudes were used to model latent classes. Correlates of class membership were assessed through multinomial logistic regression. Probability of endorsing potential vaccination facilitators were reported by class. RESULTS: Three classes of participants were identified: 'vaccine acceptant' (39%), 'vaccine hesitant' (34%) and 'vaccine resistant' (27%). Those in the hesitant and resistant groups were younger, more likely to be unstably housed and less likely to have received the current season influenza vaccine than the acceptant group. In addition, hesitant participants were less likely to report a chronic medical condition than acceptant participants. Compared to vaccine acceptant and hesitant participants, vaccine-resistant participants were more likely to predominantly inject methamphetamine and to inject drugs more frequently in the past month. Both vaccine-hesitant and resistant participants endorsed financial incentives for vaccination and hesitant participants also endorsed facilitators related to vaccine trust. DISCUSSION AND CONCLUSION: People who inject drugs who are unstably housed or predominantly inject methamphetamine are subgroups that require targeted interventions to increase COVID-19 vaccination uptake. Vaccine-hesitant people may benefit from interventions that build trust in vaccine safety and utility. Financial incentives may improve vaccine uptake among both hesitant and resistant people.

Comparison of routine blood alcohol tests and ICD-10-AM coding of alcohol involvement for major trauma patients.

BACKGROUND: Alcohol use is a key preventable risk factor for serious injury. To effectively prevent alcohol-related injuries, we rely on the accurate surveillance of alcohol involvement in injury events. This often involves the use of administrative data, such as International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM) coding. OBJECTIVE: To evaluate the completeness and accuracy of using administrative coding for the surveillance of alcohol involvement in major trauma injury events by comparing patient blood alcohol concentration (BAC) with ICD-10-AM coding. METHOD: This retrospective cohort study examined 2918 injury patients aged ≥18 years who presented to a major trauma centre in Victoria, Australia, over a 2-year period, of which 78% (n = 2286) had BAC data available. RESULTS: While 15% of patients had a non-zero BAC, only 4% had an ICD-10-AM code suggesting acute alcohol involvement. The agreement between blood alcohol test results and ICD-10-AM coding of acute alcohol involvement was fair (κ = 0.33, 95% confidence interval: 0.27-0.38). Of the 341 patients with a non-zero BAC, 82 (24.0%) had ICD-10-AM codes related to acute alcohol involvement. Supplementary factors Y90 Evidence of alcohol involvement determined by blood alcohol level codes, which specifically describe patient BAC, were assigned to just 29% of eligible patients with a non-zero BAC. CONCLUSION: ICD-10-AM coding underestimated the proportion of alcohol-related injuries compared to patient BAC. IMPLICATIONS: Given the current role of administrative data in the surveillance of alcohol-related injuries, these findings may have significant implications for the implementation of cost-effective strategies for preventing alcohol-related injuries.

The onset and severity of acute opioid toxicity in heroin overdose cases: a retrospective cohort study at a supervised injecting facility in Melbourne, Australia.

AIM: To differentiate the severity of acute opioid toxicity and describe both the clinical and physiological features associated with heroin overdose in a cohort of witnessed overdose cases. METHODS: Witnessed heroin overdose cases over a 12-month period (30 June 2018 - 30 June 2019) at the Medically Supervised Injecting Room (MSIR) in Melbourne, Australia were examined. The severity of acute opioid toxicity was classified according to the level of clinical intervention required to manage the overdose cases where an escalating level of care was provided. Heroin overdose cases were classified into one of three graded severity categories and a fourth complicated heroin overdose category. RESULTS: A total of 1218 heroin overdose cases were identified from 60,693 supervised injecting visits over the study period. On the spectrum of toxicity, 78% (n = 955) of overdose cases were classified as Grade 1 severity, 7% (n = 83) as Grade 2 severity, and 13% (n = 161) as Grade 3 acute opioid toxicity severity cases, as well as 2% (n = 19) classified as complicated heroin overdose cases. The median onset time for heroin overdose cases was 17 min (IQR 11-28 min) from the time the individual was ready to prepare and inject heroin until clinical intervention was initiated. CONCLUSION: We demonstrated that heroin overdose is a dynamic illness and cases differ in the severity of acute opioid toxicity. The risk of airway occlusion including positional asphyxia was an early and consistent feature across all levels of toxicity, while exaggerated respiratory depression together with exaggerated depression of consciousness was increasingly observed with greater levels of toxicity. We also demonstrated the importance of early intervention in overdose cases, where in a large cohort of heroin overdose cases there were no fatal outcomes, a very low hospitalisation rate and most cases were able to be managed to clinical resolution on-site.

Level and correlates of social support in a community-based sample of Australians who primarily smoke methamphetamine.

Little is known about the level and correlates of social support amongst people who use methamphetamine. We aimed to describe, and determine characteristics associated with, social support amongst a community-recruited cohort of Australians who primarily smoked methamphetamine. A cross-sectional study was conducted with data from the Victorian Methamphetamine Cohort Study (VMAX). Adults (aged ≥18 years) who used methamphetamine were recruited from June 2016 to March 2020 across metropolitan and non-metropolitan areas using convenience, snowball, and respondent-driven sampling. Social support was measured using the seven-item Enhancing Recovery In Coronary Heart Disease (ENRICHD) Social Support Inventory (ESSI). Characteristics independently associated with ESSI quartiles were assessed via multivariable partial proportional odds regression. Overall, 718 participants were included for complete-case analysis. Their mean (standard deviation [SD]) age was 34.7 (9.7) years and 62% were male. The mean (SD) and median (lower quartile-upper quartile) ESSI scores were 22.6 (7.6) and 24 (16-29), respectively, on a scale of 8 to 34 where higher scores denote better self-perceived social support. Characteristics independently associated with lower ESSI included past-year homelessness (adjusted odds ratio [aOR] = 0.49, 95% confidence interval [CI] = 0.36-0.66), moderate/severe depression (aOR = 0.60, 95% CI = 0.42-0.86), increasing age relative to <30 years (aOR[30-39] = 0.61, 95% CI = 0.41-0.91; aOR[≥40] = 0.56, 95% CI = 0.35-0.91) and greater than fortnightly methamphetamine use (aOR = 0.69, 95% CI = 0.52-0.91). Characteristics independently associated with higher ESSI were employment (aOR = 1.51, 95% CI = 1.06-2.14) and female gender (aOR = 1.39, 95% CI = 1.00-1.92). Social support services for people who use methamphetamine could be targeted and tailored to subgroups defined by correlates of social support, such as those who experience homelessness, depression or unemployment.

Trends in methamphetamine use, markets and harms in Australia, 2003-2019.

INTRODUCTION: To describe trends in methamphetamine use, markets and harms in Australia from 2003 to 2019. METHODS: Data comprised patterns of use and price from sentinel samples of people who inject drugs and who use MDMA/other illicit stimulants and population-level amphetamine-related police seizures, arrests, hospitalisations, treatment episodes and deaths from approximately 2003 to 2019. Bayesian autoregressive time-series models were analysed for: no change; constant rate of change; and change over time differing in rate after one to three changepoints. Related indicators were analysed post hoc with identical changepoints. RESULTS: The percentage of people who inject drugs reporting weekly use increased from 2010 to 2013 onwards, while use among samples of people who regularly use ecstasy and other illicit stimulants decreased. Seizures and arrests rose steeply from around 2009/10 to 2014/15 and subsequently plateaued. Price increased ($15.9 [95% credible interval, CrI $9.9, $28.9] per point of crystal per year) from around 2009 to 2011, plateauing and then declining from around 2017. Hospitalisation rates increased steeply from around 2009/10 until 2015/16, with a small subsequent decline. Treatment also increased (19.8 episodes [95% CrI 13.2, 27.6] with amphetamines as the principal drug of concern per 100 000 persons per year) from 2010/11 onwards. Deaths involving amphetamines increased (0.285 per 100 000 persons per year) from 2012 until 2016. DISCUSSION AND CONCLUSIONS: These findings suggest that problematic methamphetamine use and harms escalated from 2010 to 2012 onwards in Australia, with continued demand and a sustained market for methamphetamine. [Correction added on 30 May 2022, after first online publication: In the Abstract under 'Discussion and Conclusions' 'onwards' has been added after … 2010 to 2012].

Prevalence of alcohol and other drug use in patients presenting to hospital for fall-related injuries: a systematic review.

BACKGROUND: Alcohol and other drug (AOD) use is a key preventable risk factor for serious injuries. Prevention strategies to date have largely focused on transport injuries, despite AOD use being a significant risk factor for other injury causes, including falls. This systematic review aimed to report the prevalence of AOD use in patients presenting to hospital for fall-related injuries. METHODS: This systematic review includes studies published in English after the year 2010 that objectively measured the prevalence of AOD use in patients presenting to hospital for a fall-related injury. Screening, data extraction and risk of bias assessments were completed by two independent reviewers. Data were presented using narrative synthesis and, where appropriate, meta-analyses. RESULTS: A total of 12 707 records were screened. Full texts were retrieved for 2042 records, of which 29 were included. Four studies reported the combined prevalence of any alcohol and/or drug use, generating a pooled prevalence estimate of 37% (95% CI 25% to 49%). Twenty-two records reported on the prevalence of acute alcohol use alone and nine reported specifically on the prevalence of drugs other than alcohol, with prevalence ranging from 2% to 57% and 7% to 46%, respectively. The variation in prevalence estimates likely resulted from differences in toxicology testing methods across studies. CONCLUSIONS: AOD exposure was common in hospitalised fall-related injuries. However, research addressing prevalence across different types of falls and the use of drugs other than alcohol was limited. Future research should address these areas to improve our understanding of which populations should be targeted in AOD and injury prevention strategies . PROSPERO REGISTRATION NUMBER: CRD42020188746.

The Overdose Response with Take Home Naloxone (ORTHN) project: Evaluation of health worker training, attitudes and perceptions.

INTRODUCTION: Naloxone is a life-saving medication that reverses opioid overdose; naloxone can be provided on a 'take-home' basis so naloxone can be administered outside of the health-care setting. The Overdose Response and Take Home Naloxone (ORTHN) project established a model of care for take-home naloxone (THN) interventions across alcohol and other drug and harm reduction services in NSW, Australia. This paper evaluates the staff training and credentialing program, and examines staff attitudes and perspectives regarding the provision of THN interventions in these settings. METHODS: Staff across seven services were trained through a 'train-the-trainer' credentialing model to deliver ORTHN, including naloxone supply. Staff were surveyed regarding their experience, attitudes and knowledge on THN prior to and after training, and after 6 months. At the 6 months follow up, staff were asked about the interventions they provided, barriers and enablers to uptake, and opinions regarding future rollout. RESULTS: A total of 204 staff were trained and credentialed to provide the ORTHN intervention. Most (60%) were nurses, followed by needle syringe program workers and allied health/counsellors (32%). Linear and logistic regression analyses indicated that the training program was associated with significant improvements in staff knowledge and attitudes towards overdose and THN; however, only attitudinal improvements were maintained over time. There were high rates of staff satisfaction with the ORTHN intervention and training. DISCUSSION/CONCLUSIONS: The ORTHN program is 'fit for purpose' for broad implementation in these settings. A number of potential barriers (e.g. time, medication and staffing costs) and enablers (e.g. peer engagement, regulatory framework for naloxone supply) in implementing THN interventions were identified.

COVID-19 vaccine acceptability among people in Australia who inject drugs: Update from the 2021 Illicit Drug Reporting System interviews.

People who inject drugs may be at higher risk of COVID-19 transmission and more severe negative health outcomes following COVID-19 infection. Early research on hypothetical COVID-19 vaccines suggests this population may be less likely to accept vaccination. This commentary extends this research by presenting vaccine intention data from Illicit Drug Reporting System interviews conducted in June-July 2021, in the early stages of vaccine rollout, with people in Australia who inject drugs (N = 888). Half the sample (48%, n = 419) reported that they were hesitant to receive the COVID-19 vaccine, with key barriers relating to vaccine safety and side effect concerns. This level of hesitancy is substantially higher than that of the general population at a similar time. While we note that the subsequent Delta variant-driven third wave of cases in Australia and efforts to increase population vaccination coverage may have altered intent in this group, this level of hesitancy warrants a targeted strategy to mitigate vaccine-related concerns and maximise uptake. Ideally, this should comprise an inclusive health response that is peer-led, with peer-based organisations ideally positioned to direct immunisation service delivery and provide vaccine-related messaging.

The Role of Parental Control and Support in Declining Adolescent Drinking: A Multi-Level Study Across 30 European Countries.

BACKGROUND: Adolescent drinking has declined in many high-income countries since the early 2000s. It has been suggested that changing parenting practices may have contributed to the decline. However, previous studies investigating parenting have focused on single countries and have provided conflicting evidence. This study tested the association between changes in individual- and population-level parental control and parental support and changes in past month adolescent drinking. METHODS: A total of 271,823 adolescents aged 15-16 years, from 30 European countries between 2003 and 2015 were included in this study. Our key independent variables were adolescent reports of parental control and parental support. Our outcome measure was a dichotomous measure of any alcohol use in the 30 days before the survey, referred as past month drinking. Aggregated measures of parenting variables were used to estimate between-country and within-country effects of parenting on adolescent drinking. Data were analysed using three-level hierarchical linear probability methods. RESULTS: At the individual-level, we found a negative association between the two parental measures, i.e. parental control (ß = -0.003 and 95% CI = -0.021 to 0.017) and parental support (ß = -0.008 and 95% CI = -0.010 to 0.006) and past month drinking. This suggests adolescents whose parents exert higher control and provide more support tend to drink less. At a population level, we did not find any evidence of association on between-country and within-country parenting changes and past month drinking. CONCLUSIONS: It is unlikely that changes in parental control or support at the population-level have contributed to the decline in drinking among adolescents in 30 European countries.

An examination of the role of changes in country-level leisure time internet use and computer gaming on adolescent drinking in 33 European countries.

INTRODUCTION: Adolescent alcohol consumption has been declining in many high-income countries since the turn of this century. Research investigating the plausible explanations for these declines has been mostly based on individual-level studies, which are largely inconclusive. Changes in leisure time internet use and computer gaming (referred to in this article as 'computer activities') have been hypothesised to play a role in declining adolescent alcohol consumption at a country-level. The aim of this study was to examine the association between country-level changes over time in computer activities and adolescent drinking in 33 European countries. METHODS: This is a multi-level repeated cross-national study examining the role of changes over time in country-level and individual-level computer activities on regular drinking. We utilised four waves of the European School Survey Project on Alcohol and Drugs (ESPAD) from 2003, 2007, 2011 and 2015. At an individual-level the primary exposure of interest was daily engagement in computer activities and aggregated means were used to measure country-level daily computer activities in each included country. Data were analysed using three-level hierarchical linear probability methods. RESULTS: In the fully adjusted model, for between individual effects, we found significant positive association between daily computer activities and regular drinking (ß = 0.043, p-value <0.001 and 95% CI = 0.033-0.054). However, at a country-level, we did not find any association between within-country changes in daily computer activities and regular drinking (ß = 0.031, p-value = 0.652 and 95% CI = -0.103-0.164. CONCLUSION: Findings from this study suggest that broad cultural shifts towards increased computer-based activities among adolescents has played a little or no role in declining adolescent drinking. Future research should be directed towards examining other high-level cultural changes which may have influenced cross-national reductions in adolescent drinking.