The authors conducted a meta-analysis to summarise the evidence from prospective studies on alcohol drinking and stroke types.
Studies were identified by searching PubMed to September 1, 2016, and reference lists of retrieved articles. Additional data from 73,587 Swedish adults in two prospective studies were included. Study specific results were combined in a random-effects model.
The meta-analysis included 27 prospective studies with data on ischemic stroke (25 studies), intracerebral hemorrhage (11 studies), and/or subarachnoid hemorrhage (11 studies). Light and moderate alcohol consumption was associated with a lower risk of ischemic stroke, whereas high and heavy drinking was associated with an increased risk; the overall RRs were 0.90 (95 % CI, 0.85-0.95) for less than 1 drink/day, 0.92 (95 % CI, 0.87- 0.97) for 1-2 drinks/day, 1.08 (95 % CI, 1.01-1.15) for more than 2-4 drinks/day, and 1.14 (95 % CI, 1.02-1.28) for more than 4 drinks/day. Light and moderate alcohol drinking was not associated with any hemorrhagic stroke subtype. High alcohol consumption (>2-4 drinks/day) was associated with a non-significant increased risk of both hemorrhagic stroke subtypes, and the relative risk for heavy drinking (>4 drinks/day) were 1.67 (95 % CI, 1.25- 2.23) for intracerebral hemorrhage and 1.82 (95 % CI, 1.18-2.82) for subarachnoid hemorrhage.
As has been illustrated many times before from studies all over the world, light and moderate alcohol consumption was inversely associated with ischemic stroke (protective), whereas heavy drinking is associated with increased risk of all stroke types with a stronger association for hemorrhagic strokes.
Source: Differing association of alcohol consumption with different stroke types: a systematic review and metaanalysis. Larsson SC; Wallin A; Wolk A; Markus HS. Medicine, Vol 14, Art No 178.