4. Cardiovascular system
Alcohol affects the heart and vessels in many ways not just directly through the elevated blood pressure and increased heart rate but also indirectly through increasing the risk of obesity that leads to atherosclerosis with subsequent coronary artery disease and heart attacks.
There is also an increased risk of arrhythmias most commonly atrial fibrillation along with cardiac muscle weakness and dilated cardiomyopathy.
But the poison can be actually protective depending on the dose, some studies suggest that consuming alcohol regularly and modestly can lead to reduction in coronary artery disease risk through its antithrombotic activity and action on the lipid profile as it increases HDL cholesterol (a.k.a. the good cholesterol) concentrations in the blood and lowers LDL cholesterol (a.k.a. the bad cholesterol) concentration in the blood. It is also believed to be a good insulin sensitizer, increasing glucose metabolism, and reducing the risk of developing metabolic syndrome.
Despite the much evidence and research many doctors believe that it is dangerous for people with high risk for addiction to go with this rationale as alcoholism is a far greater problem with worse outcomes compared to the minimal cardio protective effect it provides.