Alcohol and stroke: the splitters win again

Study of the relationships of alcohol drinking and risk of stroke can readily become mired in the labyrinthine interactions of drinking categorizations, non-linear associations, disparate cardiovascular conditions, and the heterogeneous types of stroke. This Commentary discusses the recent article by Larsson et al. (BMC Medicine 14:178, 2016). The authors split their material into separate meta-analyses of subarachnoid hemorrhage, intracerebral hemorrhage, and ischemic stroke, finding disparate alcohol–stroke relationships. Our Commentary pursues the disparity theme, using the lumpers versus splitters paradigm to explore several aspects of this complex area. Please see related article: http://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-016-0721-4.