The Association of Frequency of Worry About Financial Debt With Substance Use Among Adults in Ontario, Canada.

BACKGROUND: Financial debt and associated stress might increase the risk of substance use problems or exacerbate existing ones. Little evidence is available about the degree of debt stress and its association with substance use. The objective of this study was to examine the associations of the frequency of worry about debt with heavy episodic drinking (HED), daily smoking, e-cigarette use, and cannabis use in the past 30 days. METHODS: Data were utilized from the 2020/2022 Monitor study, a repeated cross-sectional survey of adults 18 years and older in Ontario, Canada. The surveys employed a web-based panel survey of 6038 adults and collected data on debt-related stress, HED, tobacco smoking, e-cigarettes, and cannabis use in the past 30 days. Odds ratios (OR) were estimated from logistic regression models accounting for sociodemographic factors. RESULTS: Overall, 18.4% of respondents reported that they were worried about their debt most or all of the time. Accounting for household income, educational status, employment status, and other factors, the results revealed that there was a dose-response relationship between the frequency of worry about debt and substance use including daily smoking, e-cigarette use, and cannabis use in the past 30 days compared to those who were not worried at all about their debt. Sex differences were also found in the association between worry about debt and e-cigarette use. CONCLUSIONS: The frequency of worry about debt might have an important role in substance use, which suggests that financial well-being is vital in substance use prevention and harm reduction.

Combined photodynamic therapy and transpupillary thermotherapy for small choroidal melanoma.

OBJECTIVE: The objective of this study was to determine whether combining verteporfin-based photodynamic therapy (PDT) and transpupillary thermotherapy (TTT) achieves adequate tumour control while maintaining visual acuity in individuals with small choroidal melanoma of amelanotic, melanotic, and variable pigmentation. DESIGN: Individuals with posterior choroidal melanomas up to 3 mm in height underwent verteporfin-based PDT followed by immediate TTT. Further combined laser therapy was performed if a poor response was noted at 12 weeks or beyond. Tumours that demonstrated significant further growth were treated with brachytherapy or enucleation. A total of 37 eyes of 37 patients from the Terrace Eye Centre in Brisbane, Australia were studied. Average age of participants was 59.62 ± 12.45 years, and 17 of 37 participants were female (46%). METHODS: This was a retrospective, noncomparative interventional study. RESULTS: Seven of the 37 participants (19%) had recurrence of their tumour requiring further brachytherapy or enucleation. There was no statistically significant difference in visual acuity before and after treatment. There were no baseline characteristics that predicted treatment outcome. Ten individuals developed complications including epiretinal membrane (16%), scotoma (8%), cataract (3%), and macular edema (3%). No individuals experienced extraocular extension or progressed to metastatic disease. The mean follow-up time was 49 months. CONCLUSION: Combined PDT and TTT achieved 81% tumour control in this study while preserving visual acuity. However, higher rates of local recurrence compared with brachytherapy warrant close follow-up to identify recurrences early.

Associations between problem technology use, life stress, and self-esteem among high school students.

BACKGROUND: Adolescence is a critical period for development, with many risk factors resulting in long-term health consequences, particularly regarding mental health. The purpose of this study was to examine the associations between problem technology use, life stress, and self-esteem in a representative sample of adolescents residing in Ontario, Canada. METHODS: Self-reported data were obtained from a cross-sectional sample of 4,748 students (57.9% females) in grades 9 to 12 (mean age: 15.9 ± 1.3 years) who participated in the 2019 Ontario Student Drug Use and Health Survey. Problem technology use was measured using the 6-item Short Problem Internet Use Test, life stress was assessed using an item from the British Columbia Adolescent Health Survey and self-esteem was assessed using a global measure from the Rosenberg Self-Esteem Scale. Ordinal logistic regression models were adjusted for age, sex, ethnoracial background, subjective socioeconomic status, body mass index z-score, tobacco cigarette smoking, alcohol consumption and cannabis use. RESULTS: We found that 18.3% of participants reported symptoms of moderate-to-high problem technology use, although symptoms were more common in females than males (22% vs. 14.7%, respectively). Moderate-to-high problem technology use was associated with 2.04 (95% CI: 1.77-2.35) times higher odds of reporting high life stress and 2.08 (95% CI: 1.76-2.45) times higher odds of reporting low self-esteem compared to all other response options. CONCLUSIONS: Findings from this study show that problem technology use is strongly associated with higher life stress and lower self-esteem in adolescents. This study supports the importance of developing and implementing effective strategies that help to mitigate the adverse effects of problem technology use on adolescent mental health.

Effects of cannabis legalisation on patterns of cannabis consumption among adolescents in Ontario, Canada (2001-2019).

INTRODUCTION: Cannabis legalisation was enacted on 17 October 2018 in Canada. Accordingly, the effects of cannabis legalisation on patterns of cannabis consumption were examined among adolescents, including on cannabis initiation, any cannabis use, daily cannabis use and cannabis dependence. METHODS: Data from a biennial population-based, cross-sectional survey of students in Ontario were pooled in a pre-post design (2001-2019; N = 89,238). Participants provided self-reports of cannabis initiation, any cannabis use, daily cannabis use and cannabis dependence. Long-term trends in these patterns of cannabis consumption over two decades of observation were characterised to provide a broader context of usage. The effects of cannabis legalisation on patterns of cannabis consumption were quantified using logistic regression analyses. RESULTS: Long-term trends over the two decades of observation indicated that cannabis initiation decreased and then increased (p = 0.0220), any cannabis use decreased and daily cannabis use decreased (p < 0.0001 and p = 0.0001, respectively) and cannabis dependence remained unchanged (p = 0.1187). However, in comparisons between the pre-cannabis legalisation period (2001-2017) and the post-cannabis legalisation period (2019), cannabis legalisation was not associated with cannabis initiation (odds ratio; 95% confidence interval 1.00; 0.79-1.27), but it was associated with an increased likelihood of any cannabis use (1.31; 1.12-1.53), daily cannabis use (1.40; 1.09-1.80) and cannabis dependence (1.98; 1.29-3.04). DISCUSSION AND CONCLUSIONS: Cannabis legalisation was not associated with cannabis initiation, but it was associated with an increased likelihood of any cannabis use, daily cannabis use and cannabis dependence.

Cannabis legalization and cannabis use, daily cannabis use and cannabis-related problems among adults in Ontario, Canada (2001-2019).

BACKGROUND: In the context of cannabis legalization in Canada, we examined the effects on cannabis patterns of consumption, including cannabis use, daily cannabis use and cannabis-related problems. In addition, we examined differential effects of cannabis legalization by age and sex. METHODS: A pre-post design was operationalized by combining 19 iterations of the Centre for Addiction and Mental Health (CAMH) Monitor Surveys (N = 52,260; 2001-2019): repeated, population-based, cross-sectional surveys of adults in Ontario. Participants provided self-reports of cannabis use (past 12 months), daily cannabis use (past 12 months) and cannabis-related problems though telephone interviews. The effects of cannabis legalization on cannabis patterns of consumption were examined using logistic regression analyses, with testing of two-way interactions to determine differential effects by age and sex. RESULTS: Cannabis use prevalence increased from 11 % to 26 % (p < 0.0001), daily cannabis use prevalence increased from 1 % to 6 % (p < 0.0001) and cannabis-related problems prevalence increased from 6 % to 14 % (p < 0.0001) between 2001 and 2019. Cannabis legalization was associated with an increased likelihood of cannabis use (OR, 95 % CI: 1.62, 1.40-1.86), daily cannabis use (1.59, 1.21-2.07) and cannabis-related problems (1.53, 1.20-1.95). For cannabis-related problems, a significant two-way interaction was observed between cannabis legalization and age (p = 0.0001), suggesting differential effects among adults ≥55 years. CONCLUSIONS: Cannabis legalization was associated with an increased likelihood of cannabis use, daily cannabis use and cannabis-related problems. Given increases in these cannabis patterns of consumption, broader dissemination and uptake of targeted prevention tools is indicated.

Machine learning applications in tobacco research: a scoping review.

OBJECTIVE: Identify and review the body of tobacco research literature that self-identified as using machine learning (ML) in the analysis. DATA SOURCES: MEDLINE, EMABSE, PubMed, CINAHL Plus, APA PsycINFO and IEEE Xplore databases were searched up to September 2020. Studies were restricted to peer-reviewed, English-language journal articles, dissertations and conference papers comprising an empirical analysis where ML was identified to be the method used to examine human experience of tobacco. Studies of genomics and diagnostic imaging were excluded. STUDY SELECTION: Two reviewers independently screened the titles and abstracts. The reference list of articles was also searched. In an iterative process, eligible studies were classified into domains based on their objectives and types of data used in the analysis. DATA EXTRACTION: Using data charting forms, two reviewers independently extracted data from all studies. A narrative synthesis method was used to describe findings from each domain such as study design, objective, ML classes/algorithms, knowledge users and the presence of a data sharing statement. Trends of publication were visually depicted. DATA SYNTHESIS: 74 studies were grouped into four domains: ML-powered technology to assist smoking cessation (n=22); content analysis of tobacco on social media (n=32); smoker status classification from narrative clinical texts (n=6) and tobacco-related outcome prediction using administrative, survey or clinical trial data (n=14). Implications of these studies and future directions for ML researchers in tobacco control were discussed. CONCLUSIONS: ML represents a powerful tool that could advance the research and policy decision-making of tobacco control. Further opportunities should be explored.

Cross-sectional Study of Factors Associated With Suicide Ideation in Ontario Adolescents.

OBJECTIVE: Suicide is the second leading cause of death in Canadian adolescents. The Interpersonal Theory of Suicide attempts to explain suicide etiology and proposes that feelings of perceived burdensomeness or thwarted belongingness lead to suicide ideation, but this has not been extensively studied in adolescents. This study aimed to use the Interpersonal Theory of Suicide to examine factors that may be associated with suicide ideation in adolescents. The factors of interest were school connectedness, perceived availability of support, self-esteem, feelings of worthlessness, feelings of hopelessness, bullying and cyberbullying victimization, substance use, and social media use. METHODS: Data were from the 2017 Ontario Student Drug Use and Health Survey, a survey of 7th to 12th graders enrolled in a publicly funded school in Ontario. Weighted multivariate logistic regression of suicide ideation on all exposure variables was conducted. RESULTS: 13.6% of students in the sample endorsed having suicidal ideation in the preceding 12 months. Not knowing where to turn to for support, feeling worthless, endorsing low self-esteem, being bullied, and using cannabis were each associated with greater odds of suicide ideation. Feeling hopeless, social media use, using alcohol and tobacco, and being cyberbullied were not associated with suicide ideation in the weighted multivariate logistic regression model. CONCLUSIONS: This study is consistent with the Interpersonal Theory of Suicide as low self-esteem and feelings of worthlessness, two indicators of perceived burdensomeness, and not knowing where to turn to for support, an indicator of thwarted belongingness, were associated with greater odds of suicide ideation. These findings can help guide interventions aimed at reducing the burden of suicidality during adolescence and demonstrate the need to provide accessible mental health support for youth.

Exploring the Association of e-Cigarette and/or Cannabis Use with Heavy Episodic Drinking among Ontario Adults.

Background: The use of electronic cigarettes and cannabis has significantly increased in recent years, which raises public health concerns. There are also concerns about the association of these substances with drinking behaviors. The main objective of the present study is to examine the association of e-cigarettes and/or cannabis use with heavy episodic drinking (HED) among Ontario adults. Methods: The sample consisted of 5,564 adults from the Monitor Survey in 2018 and 2019. Cannabis and e-cigarette use reflected any use of the substances in the past 12 months. HED was defined as consumption of four/five or more drinks on a single occasion at least monthly in the past 12 months. Odds ratios (OR) were estimated from logistic regression models accounting for complex survey design and sociodemographic factors. Results: Overall, the prevalence of HED was 17.5% in 2018 and 2019. Among participants who reported both e-cigarette and cannabis use, about one-half (50.4%) reported HED at least monthly. Adjusting for covariates, the odds of HED were 5.71 (95%CI, 3.92-8.30) times higher among those who reported both e-cigarette and cannabis use compared to those who used neither substance. Conclusions: The use of e-cigarettes and cannabis are significantly associated with heavy episodic drinking among adults, indicating that those who engage in the dual use of e-cigarette and cannabis may be an important group to target with intervention programs.

A machine learning approach to predict e-cigarette use and dependence among Ontario youth. / Une approche d'apprentissage automatique pour prédire l'utilisation des cigarettes électroniques et la dépendance à celles-ci chez les jeunes de l'Ontario.

INTRODUCTION: We developed separate random forest algorithms to predict e-cigarette (vaping) ever use and daily use among Ontario youth, and subsequently examined predictor importance and statistical interaction. METHODS: This cross-sectional study used a representative sample of Ontario elementary and high school students in 2019 (N = 6471). Vaping frequency over the last 12 months was used to define ever-vaping and daily vaping. We considered a large set of individual characteristics as potential correlates for ever-vaping (176 variables) and daily vaping (179 variables). Using cross-validation, we developed random forest algorithms and evaluated model performance based on the C-index, a measure to assess the discriminatory ability of a model, for both outcomes. Further, the top 10 correlates were identified by relative importance score calculation and their interaction with sociodemographic characteristics. RESULTS: There were 2064 (31.9%) ever-vapers, and 490 (7.6%) of the respondents were daily users. The random forest algorithms for both outcomes achieved high performance, with C-index over 0.90. The top 10 correlates of daily vaping included use of caffeine, cannabis and tobacco, source and type of e-cigarette and absence in last 20 school days. Those of ever-vaping included school size, use of alcohol, cannabis and tobacco; 9 of the top 10 ever-vaping correlates demonstrated interactions with ethnicity. CONCLUSION: Machine learning is a promising methodology for identifying the risks of ever-vaping and daily vaping. Furthermore, it enables the identification of important correlates and the assessment of complex intersections, which may inform future longitudinal studies to customize public health policies for targeted population subgroups.

Correlates of driving after cannabis use in high school students.

Driving under the influence of cannabis is a growing public health concern among young people. This study assessed the prevalence of cannabis-impaired driving and its related sociodemographic, psychological, and knowledge-based correlates among Canadian adolescents. The sample for this study were drawn from the 2017 Ontario Student Health and Drug Use Survey (OSDUHS), consisting of high school students with valid driver's licenses (mean age = 16.8, SD = 0.71) who were asked about their driving behaviors, drug use, and attitudes regarding cannabis use (N = 1161). A multivariable logistic regression model was performed to determine the strongest correlates of driving after cannabis use. The prevalence of past-year driving within an hour of cannabis use was 10.3% (95% CI: 7.8,13.5). In the final multivariable model, probable cannabis dependence (OR = 12.7, 95%CI: 3.4,47.7), low perceived risk of cannabis use (OR = 5.3, 95%CI: 2.5,11.1), pro-legalization attitudes, (OR = 4.3, 95%CI: 2.0,9.1) and male gender (OR = 2.6, 95%CI: 1.5,4.5) were significantly associated with driving under the influence of cannabis. Other correlates of driving after cannabis user were risky driving behaviors, including past-year texting and driving and driving after alcohol use. There are various correlates of driving under the influence of cannabis, including attitudes related to cannabis which may be amenable to intervention. Future efforts should continue to monitor the prevalence of cannabis-impaired driving in this population and determine whether changes in students' attitudes surrounding cannabis are linked to behavioural changes.

24-h Movement Guidelines and Substance Use among Adolescents: A School-Based Cross-Sectional Study.

Children and youth are recommended to achieve at least 60 min/day of moderate-to-vigorous physical activity, no more than 2 h/day of recreational screen time, and a sleep duration of 9-11 h/night for 11-13-year-olds or 8-10 h/night for 14-17-year-olds. Meeting the physical activity, screen time, and sleep duration recommendations have previously been associated with substance use among adolescents. However, previous research has mainly examined these factors individually rather than looking at how these indicators could concurrently relate to substance use in this age group. Therefore, this study examined the associations between meeting the 24-h movement guidelines for screen time, sleep duration, and physical activity (independent variables) with substance use outcomes including alcohol consumption, cannabis use, and cigarette smoking (dependent variables) among adolescents. Self-reported data from a cross-sectional and representative sample of 10,236 students (mean age = 15.1 years) in Ontario, Canada were analyzed. Logistic regression models stratified by gender were adjusted for potential confounders. Combinations of 24-h movement guidelines was differentially associated with substance use in boys and girls. Overall, findings showed that meeting 24-h movement guidelines is associated with lower odds of alcohol consumption, cannabis use, and cigarette smoking differentially with type of recommendation met and gender. Given that the associations between 24-h movement guidelines and substance use differ between boys and girls, future efforts should take this into consideration.

Young drivers vs. non-drivers: are there differences in behaviour?

BACKGROUND: Traditionally, a first step toward independence for a North American youth has been to obtain a driver's licence. Licensure can be associated with freedom and independence to provide teens opportunities to participate in conventional and health-enhancing behaviours, such as school, work, sporting events and other social activities, and/or provide opportunities to engage in unconventional, risk taking and health compromising behaviours. Yet, recent trends show that youth are delaying getting their licence. OBJECTIVE: The purpose of this study was to use the constructs of conventional and unconventional behaviours identified in Problem Behaviour Theory (PBT) under the behaviour system to examine whether driver licensure status in youth was associated with conventional, health-enhancing behaviours or unconventional, health compromising, risky behaviours. METHOD: Data were derived from the 2015 and 2017 cycles of the Ontario Student Drug Use Survey (OSDUHS). Analyses are based on a subsample of students who were at least 16 years of age. Included measures: driver's licence (at least a G1 - the first stage of a 3-stage graduated licensing system), conventional behaviours (academic performance, school connectedness, employment, physical activity, and sleep), unconventional behaviours (tobacco use, cannabis use, alcohol use, binge drinking, hazardous drinking, problematic drug use, screen time, and number of antisocial behaviours), and control factors (age, sex, region, family Socio-Economic Status (SES)). RESULTS: 67.97 % of youth 16-19 years of age obtained a driver's licence. Of the sample, 71.80 % of males, 75.05 % not living in the Greater Toronto Area (GTA), and 70.86 % of youth with an average family SES received their driver's licence. In regression analyses, older youth, males, and youth not living in the GTA had significantly higher odds of obtaining a driver's licence than younger youth, females, and youth living in the GTA. Conventional behaviours that were significantly positively associated with licensure status included youth who had high academic achievement, good social connectedness, and who were employed. Unconventional behaviours that were significantly positively associated with licensure status included alcohol use and binge drinking. DISCUSSION: In agreement with Problem Behaviour Theory, the results show that youth who obtain their licence show limited problematic lifestyle or 'proneness' (Gohari, 2019). Alcohol use and binge drinking were significantly associated with youth obtaining a driver's licence but hazardous drinking was not. This study suggests that a driver's licence for youth could both control but also instigate unconventional behaviours as identified by PBT. A driver's licence could also provide opportunities for conventional behaviours associated with education and school connectedness. However, the independence provided by a driver's licence could offer youth unsupervised social opportunities to drink and binge drink that may be health-compromising. Thus, based on PBT, licensure status is associated with both conventional behaviours, as well as problem behaviours associated with alcohol use.

Nonmedical use of prescription opioids, psychological distress, and suicidality among adolescents.

PURPOSE: The present study examined associations between nonmedical use of prescription opioids and serious psychological distress, suicidal ideation, and suicide attempts, and tested whether age and sex moderate these relationships. METHODS: Data on 5582 adolescents were obtained from a representative province-wide survey of students in grades 7 through 12 (mean age: 15.3 years) across Ontario, Canada. Nonmedical use of prescribed opioids in the last 12 months was categorized in "no use", "infrequent use (1-2 times)", and "regular use (3 times or more)". Logistic regression analysis was adjusted for age, sex, ethnicity, subjective socioeconomic status, and other substance use (i.e., tobacco cigarette, alcohol, cannabis). RESULTS: Overall, regular nonmedical use of prescription opioids was strongly associated with greater odds of serious psychological distress (OR: 3.47; 95% CI 1.42-8.45), suicidal ideation (OR: 2.73; 95% CI 1.84-4.05), and suicide attempts (OR: 3.21; 95% CI 1.40-7.37). However, infrequent nonmedical use of prescription opioids was associated with greater odds of serious psychological distress (OR: 1.79; 95% CI 1.08-2.98) and suicidal ideation (OR: 1.63; 95% CI 1.20-2.21), but not suicide attempts (OR: 1.84; 95% CI 0.76-4.45). Age-stratified analyses showed that both infrequent (OR: 1.61; 95% CI 1.01-2.58) and regular (OR: 3.40; 95% CI 2.11-5.46) nonmedical use of prescription opioids was strongly associated with greater odds of suicidal ideation among 15- to 20-year-olds, but not 11- to 14-year-olds. CONCLUSION: These findings suggest that nonmedical use of prescription opioids is strongly associated with mental health problems among adolescents. Future research using a longitudinal design is needed to confirm age differences and temporality.

Prevalence and Correlates of Medicinal Cannabis Use Among Adolescents.

PURPOSE: Prior studies of medicinal cannabis use (MCU) have focused primarily on adults. This study examined the prevalence and correlates of self-reported MCU among adolescents. METHODS: Secondary school students (grades 9-12; N = 3,221) completed a cross-sectional survey in classrooms across Ontario, Canada, in 2016-2017. Participants reported on cannabis use behavior, cannabis dependence, other drugs use, and general health and sleep. Participants reporting cannabis use in the past year were grouped based on whether they reported MCU or not (i.e., recreational cannabis use only [RCU-only]). RESULTS: An estimated 6.89% (95% confidence interval 5.48%-8.63%) of students reported MCU, representing one quarter of the students reporting current cannabis use. Relative to the RCU-only group, the MCU group reported using cannabis more frequently, were more likely to report vaping and eating cannabis, had greater risk for cannabis dependence, perceived cannabis as less harmful, were more likely to report tobacco use, recreational use of other drugs, and medicinal use of sedatives or tranquilizers, and were less likely to report good health and sleeping for seven or more hours per night. Frequency of cannabis use accounted for differences between MCU and RCU-only groups in cannabis dependence risk, recreational use of other drugs, and perceiving cannabis as harmful, but it did not account for the other differences. CONCLUSIONS: A sizable portion of secondary school students report MCU, which appears to be associated with more frequent cannabis use and certain substance use and health-related correlates. Research is needed to further characterize motives for self-reported MCU among adolescents.

Genomic analysis of adult case of ocular surface giant congenital melanocytic nevus and associated clinicopathological findings.

INTRODUCTION: Conjunctival nevi are the most common tumor of the ocular surface. There are some rare reports of so-called 'giant' conjunctival nevi. We report a case of a 47-year-old female with a cutaneous and ocular surface giant congenital melanocytic nevus and describe her clinical course. CASE DESCRIPTION: This is a retrospective case report of a single patient. A 47-year-old female with a history of biopsy-proven periorbital congenital melanocytic nevus, with an associated giant conjunctival nevus presented for structural and functional rehabilitation. Serial surgeries were performed and excised tissue was sent for histopathological and genetic examination. The conjunctival nevus had a low tumor mutation burden, and of the 647 somatic mutations, only one occurred within a protein coding region, namely NRAS p.Gln61Arg. CONCLUSION: This is the first reported adult case including genomic analysis of an ocular surface giant congenital melanocytic nevus. The case shows a possible association between periorbital congenital melanocytic nevi and giant conjunctival nevi, and underscores the possible role that targeted drug therapies may have in malignant transformation of these conditions.

Energy Drink Consumption and Substance Use Among Middle and High School Students.

This study examined the association between energy drink consumption and substance use among adolescents and tested whether sex and/or grade level (i.e., middle vs. high school) moderate the association. Data were derived from the 2017 Ontario Student Drug Use and Health Survey, a representative survey of students in 7th to 12th grade. Analyses included 10,662 students who self-reported information on energy drink consumption and substance use. Poisson regression models were used with adjustments for important covariates. Energy drink consumption was associated with tobacco cigarette smoking (incidence rate ratio (IRR): 3.74; 95% confidence interval (CI): 3.22-4.35), cannabis use (IRR: 2.90; 95% CI: 2.53-3.32), binge drinking (IRR: 2.46; 95% CI: 2.05-2.96), opioid use (IRR: 2.23; 95% CI: 1.85-2.68), and alcohol use (IRR: 1.31; 95% CI: 1.26-1.36). The associations of energy drink consumption with tobacco cigarette smoking, cannabis use, and alcohol consumption were modified by grade level (two-way interaction terms p < 0.05). The association between energy drink consumption and substance use was generally much stronger among middle school students compared with high school students. The findings suggest that middle school students may be more vulnerable to the negative effects of energy drinks in relation with substance use.

Whole genome landscapes of uveal melanoma show an ultraviolet radiation signature in iris tumours.

Uveal melanoma (UM) is the most common intraocular tumour in adults and despite surgical or radiation treatment of primary tumours, ~50% of patients progress to metastatic disease. Therapeutic options for metastatic UM are limited, with clinical trials having little impact. Here we perform whole-genome sequencing (WGS) of 103 UM from all sites of the uveal tract (choroid, ciliary body, iris). While most UM have low tumour mutation burden (TMB), two subsets with high TMB are seen; one driven by germline MBD4 mutation, and another by ultraviolet radiation (UVR) exposure, which is restricted to iris UM. All but one tumour have a known UM driver gene mutation (GNAQ, GNA11, BAP1, PLCB4, CYSLTR2, SF3B1, EIF1AX). We identify three other significantly mutated genes (TP53, RPL5 and CENPE).