Social media use and adolescent health-risk behaviours: A systematic review and meta-analysis

Objectives To examine the association between social media (SM) use and health-risk behaviours: alcohol/drug/tobacco/electronic nicotine delivery system (ENDS) use, unhealthy dietary behaviour, inadequate physical activity, gambling, anti-social, sexual risk, and multiple risk behaviours in adolescents aged 10-19 years. Design Systematic review and meta-analysis. Data sources Embase, MEDLINE, APA PsycINFO, SocINDEX, CINAHL, SSRN, SocArXic, PsyArXiv, MedRxiv, and Google Scholar (01/1997-06/2022). Methods Included studies reported a SM exposure (time spent, frequency of use, exposure to health-risk behaviour content or other SM activities) and ≥1 relevant outcome. Screening and risk of bias (RoB) assessments were completed independently by two reviewers. Synthesis without meta-analysis (SWiM) based on effect direction and random-effects meta-analyses were used. Effect modification was explored using meta-regression and stratification. Certainty of evidence was assessed using GRADE (Grading of Recommendations, Assessment, Development and Evaluations). Results Of 17,077 studies screened, 126 were included (76 meta-analysed). The final sample included 1,431,534 adolescents (mean age:15.0 years). SWiM indicated harmful associations between SM and all health-risk behaviours in most included studies, except inadequate physical activity where beneficial associations were reported in 63.6% of studies. Frequent (vs infrequent) SM use was associated with increased alcohol consumption (OR 1.48, 1.32 to 1.62; n=383,670), drug use (1.28, 1.05 to 1.56; n=117,646), tobacco use (1.78, 1.45 to 2.19; n=424,326), sexual risk (1.78, 1.49 to 2.13; n=47,325), anti-social behaviour (1.73, 1.44 to 2.06; n=54,993), multiple risk behaviours (1.75, 1.30 to 2.35; n=43,571), and gambling (2.84, 2.04 to 3.97; n=26,537). Exposure to health-risk behaviour content on SM (vs no exposure) was associated with increased odds of ENDS use (1.73, 1.34 to 2.23; n=721,322), unhealthy dietary behaviour (2.12, 1.87 to 2.39; n=9424), and alcohol consumption (2.43, 1.25 to 4.71; n=14,731). For alcohol consumption, stronger associations were identified for exposure to user-generated content (3.21, 2.37 to 4.33) vs marketer-generated content (2.18, 0.96 to 4.97). For time spent on SM, use for ≥2hrs/day (vs <2hrs) increased odds of alcohol consumption (2.13, 1.56 to 2.92; n=12,390). GRADE certainty was moderate for unhealthy dietary behaviour, low for alcohol use and very low for other investigated outcomes. Conclusions Social media use is associated with adverse adolescent health-risk behaviours, but further high quality research is needed to establish causality, understand effects on health inequalities, and determine which aspects of social media are most harmful. Given the pervasiveness of social media, efforts to understand and reduce the potential risks adolescents face may be warranted. Funding, competing interests, data sharing Funded by the Medical Research Council, Chief Scientist Office, NHS Research Scotland and the Wellcome Trust. All authors declare no competing interests. Template data forms, data extracted, and data analysed are available from the corresponding author on request. Systematic review registration PROSPERO: CRD42020179766. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Protocols ### Funding Statement This work was supported by the Medical Research Council (MC\_UU\_00022/2), Chief Scientist Office (SPHSU17), an NHS Research Scotland Senior Clinical Fellowship (SCAF/15/02) and the Wellcome Trust (218105/Z/19/Z, 205412/Z/16/Z). The funders played no active role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data analysed were based on published data. Template data forms, the data extracted from included studies and data used for analyses are available from the corresponding author on reasonable request. The study protocol is published on PROSPERO: (ID: CRD42020179766)