1168Are there non-linear alcohol–health relationships?: Review of observational studies employing enhanced causal methods. (2nd September 2021) - Visontay, Rachel
Abstract: Focus of Presentation: Research has long found 'J-shaped' relationships between alcohol consumption and certain health outcomes, indicating a protective effect of moderate consumption. However, methodological limitations in most studies hinder causal inference. While enhanced methods for data analysis (e.g. G-methods) and alternative observational designs (e.g. Mendelian Randomisation) have been developed, they are not commonly applied to alcohol–health research. This presentation will report on a systematic review of observational studies that employ improved approaches to mitigate confounding in characterising alcohol–long-term health relationships (PROSPERO registration: CRD42020185861). Findings: MEDLINE, PsycINFO, Embase and SCOPUS were searched in May 2020, yielding 16 published manuscripts reporting on cancer, diabetes, dementia, mental health, cardiovascular health, mortality, HIV seroconversion, and musculoskeletal health. Study findings were qualitatively synthesised. A variety of functional forms were found, including reverse J/J-shaped relationships for prostate cancer and related mortality, dementia risk, mental health, and certain lipids. However, most outcomes were only evaluated by a single study, and few studies provided information on the role of alcohol consumption pattern. Conclusions/Implications: More research employing enhanced causal inference methods is urgently required to accurately characterise alcohol–long-term health relationships. Those studies that have been conducted find a variety of linear and non-linear functional forms, with results tending to be discrepant even within specific health outcomes. Key messages: A systematic review found that those studies of alcohol–long-term health relationships employing enhanced causal methods are too few and inconsistent to establish whether non-linear alcohol–health relationships exist.