Alcohol consumption – regardless of type of alcoholic beverage – of 30 grams or less per day is not associated with increased risk of subarachnoid hemorrhage1. A higher alcohol intake however, does increase the risk. Researchers concluded this after examining the data of 14 observational studies with over 480.000 people in a so-called meta-analysis. Previously, the evidence for an association between this type of stroke and alcohol consumption was not clear. Therefore, Chinese researchers decided to examine all data available on this topic. It remains unclear which mechanism causes the association with heavy alcohol consumption and why the association was not found with moderate alcohol consumption.
A subarachnoid hemorrhage is a type of stroke that causes bleeding in the space between the skull and brains. It is caused by a rupture in a blood vessel. This type of stroke is not so common. The most prevalent type of stroke (85%) is the ischaemic stroke2. Previous research shows that moderate alcohol consumption is associated with a risk reduction for ischaemic stroke. This type of stroke is caused by a blood clot that blocks an artery in the brain. The risk of experiencing an ischaemic stroke is at its lowest with a relative risk decrease of 20% when consuming 15 grams of alcohol per day3. Above this level the risk starts to increase, this is called a J-shaped curve.
- Yao X, Zhang K, Bian J, Chen G. (2016). Alcohol consumption and risk of subarachnoid hemorrhage: A meta-analysis of 14 observational studies. Biomed Rep, (5):4.
- Go AS, Mozzaffarian D, Roger VL et al. (2013). Heart Disease and Stroke Statistics—2013 Update. A Report From the American Heart Association. Circulation, 127(1):e6-e245.
- Ronksley PE, Brien SE, Turner BJ et al. (2011). Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ, 342:d671.