Colorectal cancer (CRC) is the fourth most common cancer in the UK and second leading cause of cancer-related deaths. The faecal immunochemical test (FIT) is a non-invasive home-based test used for both symptomatic assessment and population-based screening. However, approximately 30% of screening FIT kits and 10% of symptomatic FIT kits are never returned. Under-served populations, including ethnic minorities, socioeconomically deprived communities and those with mental health conditions, experience particularly low FIT return rates, contributing to health inequalities in CRC outcomes. This systematic review aims to synthesise evidence on the effectiveness and acceptability of interventions to improve FIT returns in both asymptomatic screening and symptomatic populations, with particular focus on under-served communities.

We will conduct a systematic review of qualitative and quantitative evidence. We will search Scopus, MedLine via Ovid, CINAHL via Ebsco and Cochrane Central Register of Controlled Trials from September 2010 onwards, supplemented by reference screening and trial registry searches. Eligible studies will include randomised controlled trials, quasi-experimental studies, observational studies, qualitative studies, mixed-methods studies and implementation studies examining FIT interventions in screening or symptomatic populations. Two reviewers will independently screen search results for eligible studies. Data extraction will capture study characteristics, population demographics, intervention components and outcomes including FIT return rates, acceptability, feasibility and implementation factors. Quantitative data will undergo systematic tabulation and meta-analysis where appropriate, with narrative synthesis for heterogeneous studies. Qualitative data will be analysed using framework-based thematic analysis, mapping findings to both the theoretical domains framework and theoretical framework of acceptability. A mixed-methods synthesis will integrate quantitative and qualitative findings to identify intervention characteristics, implementation strategies and contextual factors associated with improved outcomes across different population groups.

Ethics approval is not required as this systematic review will analyse published studies. Findings will be disseminated through peer-reviewed publication and conference presentations.

CRD420251111663.

To assess the prevalence of depression or depressive symptoms among engineering students.

Systematic review and meta-analysis of prevalence surveys using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

PubMed, Index Medicus Global, EMBASE, Web of Science, Scopus and PsycINFO were searched from 1 January 2003 to 28 June 2024.

Studies were included if they: (1) reported the prevalence of depression or depressive symptoms among engineering students, (2) used a validated instrument with defined cut-off points to assess depression or depressive symptoms and (3) were published in a peer-reviewed journal.

Two researchers independently extracted data using a standardised spreadsheet, collecting information on country of data collection, survey years, year of training, sample size, mean age of participants, number and percentage of male participants, assessment instrument, cut-off points and prevalence estimates. Discrepancies were resolved by a third researcher. Risk of bias was assessed with the Risk of Bias for Studies of the Prevalence of Mental Health Disorders tool. Prevalence estimates were synthesised using random-effects meta-analysis. Between-study heterogeneity was assessed with ² tests and the I² statistic. Subgroup analyses were conducted according to severity cut-off points, and meta-regression was used to explore the influence of study-level characteristics on prevalence estimates.

23 studies involving 12 758 students across 11 countries were analysed. All studies used validated scales with cut-off points to assess depression or depressive symptoms. The overall pooled prevalence was 42.6% (95% CI 32.7 to 53.1) for studies using symptom severity cut-off points at mild or above, and 33.1% (95% CI 25.2 to 42.0) for studies using symptom severity cut-off points at moderate or above. Meta-regression indicated a progressive annual increase in prevalence (OR 1.14, 95% CI 1.01 to 1.28, p=0.034) across studies conducted from 2014 to 2024.

Prevalence of depression and depressive symptoms is high among engineering students, at levels comparable to medical students. Given the substantial impact, further research should investigate risk factors and evaluate preventive, early detection and treatment strategies tailored to engineering students.

CRD42024571131.