Alcohol is a major public health issue. The volume of alcohol consumed, and the pattern of consumption are key factors in determining alcohol use-related harms [1]. The World Health Organization (WHO) considers harmful use of alcohol a causal factor in over 200 disease and injury conditions, whereby harmful use encompasses that which causes adverse health and social consequences to the drinker, those around the drinker and wider society, and patterns of use associated with detrimental health impacts [2, 3] The spectrum of adverse health consequences due to harmful alcohol use includes alcohol-related cancers, liver and cardiovascular disease, mental and behavioural disorders, and physical and psychological injuries due to alcohol-related violence and road traffic accidents [3]. In 2016, 5.3% of deaths and 5.1% of disability-adjusted life years (DALYs) globally were attributed to alcohol [3]. The non-health sectors impacts of alcohol-related harm, such as increased crime, economic losses and lost workforce productivity, are also significant [2].

Many factors influence the volume and pattern of alcohol consumption at a population level, from the level of the individual and community, to the broader sociocultural, legislative and policy context [3]. As a result, there are substantial geographic differences in alcohol consumption internationally [4]. In 2019, the average volume of alcohol consumed across all 38 Organisation for Economic Co-operation and Development (OECD) countries was 8.7 L per capita, ranging from 12.9 L in Lativa to 0.1 L in Indonesia [5]. Global changes in consumption trends over time were described in the 2018 WHO Global Status Report on Alcohol and Health [6]. While the WHO European Region has the highest per capita alcohol consumption, this has decreased over time, alongside stable consumption trends in the African Region, Americas and Eastern Mediterranean Regions, and increases in the Western Pacific and Southeast Asia Regions [2].

Patterns of alcohol consumption also vary by country. WHO considers heavy episodic drinking (HED)—defined as consumption of at least 60 g of pure alcohol at least once in the previous 30 days, and often referred to colloquially as binge drinking—the best indicator for alcohol consumption patterns associated with adverse health consequences [7]. While the overall prevalence of HED has decreased globally since 2000 (22.6% to 18.2% in 2016), in certain countries of Eastern Europe and Sub-Saharan Africa it remains high at over 60% of current drinkers [6]. In Europe, the 2016 prevalence of 30-day HED ranged from 62.3% in Lithuania to 28.3% in Ukraine [4].

In the Republic of Ireland (referred to as Ireland hereafter), nationally representative population-level surveys such as the annual Healthy Ireland Survey and National Drug and Alcohol Survey have identified a high prevalence of binge drinking (using a definition of consuming six or more standard drinks in a single drinking occasion) among the Irish population, with an overall declining trend over time [8, 9]. In the 2021 Healthy Ireland Survey, 22% of Irish drinkers aged 15 and older (15% of the population) reported binge drinking in a typical drinking occasion, a decrease compared to 37% of drinkers and 28% of the population respectively in 2018 [8]. The 2019–2020 National Drug and Alcohol Survey identified a more nuanced trend, with a decrease since 2002–2003 in monthly HED among 15–24 and 25–34 year olds (73.7% to 56.4%) accompanied by a stable and increased prevalence among 35–49 and 50–64 year olds respectively [9]. Sociodemographic differences in binge drinking have also been identified among the Irish population. The 2016 Healthy Ireland Survey found binge drinking to be more common among Irish men (35%) compared to women (10%), among younger age groups (31% of drinkers aged under 25) compared to older (13% of drinkers aged 65 or older), and among those living in disadvantaged areas (43%) compared to more affluent areas (33%) [8].

Adolescence, a period of biological, cognitive, emotional and social development, is when alcohol use typically begins [1, 10]. This is of significant concern, given adolescents are more vulnerable to the adverse health effects of alcohol consumption compared to adults. Harmful patterns of alcohol consumption, such as binge drinking, may emerge during adolescence and become established. This pattern of consumption places adolescents at greater risk of experiencing alcohol-related harm as well as other substance use in later life [10–12]. In the 2019 European School Survey Project on Alcohol and Other Drugs (ESPAD) Survey, one in three students (34%) from the 35 participating countries reported at least one episode of HED (defined as consumption of five or more drinks in a single occasion) in the previous 30 days [13]. Since 1995, 30-day HED prevalence as measured by ESPAD has increased among females (30% to 34%) and decreased for males (41% to 36%). Among Irish adolescents, there was a 32% 30-day prevalence of HED in ESPAD 2019 (33% for males and 32% for females) – a notable increase from 2015 (28%) and change from a previously declining trend since 2003. Understanding the determinants of binge drinking among adolescents is important to inform public health policy and intersectoral action to protect adolescents from alcohol-related harm. This knowledge can also inform comparisons between countries. A substantial body of international literature has examined possible determinants of adolescent binge drinking, generally termed ‘risk factors’ and ‘protective factors’. These factors are frequently grouped into specific domains—for example, factors at the sociodemographic level of the individual, as well as those specific to adolescents’ wider social environment, such as parental, peer, school and local community-related factors. There is heterogeneity in measurement of these exposure variables across the literature, and in definitions of binge drinking with respect to the volume of alcoholic drinks consumed and the time period in which consumption is measured.

While the body of international literature on risk and protective factors for binge drinking is sizeable, examination of risk and protective factors for binge drinking specifically among adolescents living in the Ireland is a notably understudied area in comparison to other high-income countries. Therefore, to further understanding of determinants of adolescent binge drinking in Ireland, this study aimed to examine the prevalence of, and potential risk and protective factors associated with, binge drinking among a cohort of 15–16-year-old adolescents in the West of Ireland who participated in the Planet Youth 2020 Survey.