ARTICLE Stanesby_PONE_2019/IDIAP The contexts of heavy drinking: A systematic review of the combinations of context-related factors associated with heavy drinking occasions Stanesby, Oliver Labhart, Florian Dietze, Paul Wright, Cassandra Kuntsche, Emmanuel EXTERNAL PUBLIC PLOS ONE 14 7 29 2019 URL doi Background The amount of alcohol consumed during an occasion can be influenced by physical and social attributes of the setting, characteristics and state of individuals, and the interactions of these components. This systematic review identifies and describes the specific combinations and sequences of context-related factors that are associated with heavy drinking occasions. Materials and methods We conducted a systematic literature search of MEDLINE, Embase and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases. Eligible articles were event-level and event-based studies that quantitatively analysed associations of sequences or combinations of context-related factors with event-level alcohol consumption. We extracted information on study design, sample, variables, effect estimates and analytical methods. We compiled a list of combinations and sequences associated with heavier drinking (i.e., ‘risky contexts’) and with lighter drinking (‘protective contexts’). The review protocol was registered with PROSPERO (registration number: CRD42018089500). Results We screened 1902 retrieved records and identified a final sample of 65 eligible studies. Daily mood, day of week, location and drinking group characteristics are important drivers of whether an individual engages in a heavy drinking occasion. The direction and magnitude of some associations differed by gender, age, personality and motives, such that in particular social or physical contexts, some people may feel compelled to drink more while others are compelled to drink less. Very few sequences of factors were reported as being associated with event-level alcohol consumption. Conclusions Contexts or factors are experienced in specific sequences that shape the broader drinking context and influence drinking behaviours and consequences but are under-studied. Event-level studies such as those using ecological momentary assessment can harness new technologies for data collection and analysis to improve understandings of why people engage in heavy drinking. Continued event-level research will facilitate public health interventions and policies that reduce heavy drinking and alcohol-related harms.