Research Study on the Effects of Smoking on Arteries

Inclusion Criteria: * Chronic smokers (of between 4 and 20 years duration) and non-smokers will be recruited to the GCRC. Smokers will be allocated to a "light" group, smoking 4-10 cigarettes per day and a "heavy" smoking group who smoke 11-20 cigarettes per day. * Non-smokers will be defined as those with a life time consumption of no more than 20 cigarettes, do not live or work in a smoky atmosphere. * All individuals will have a normal history and clinical examination, including a normal EKG, urinalysis and serum chemistry, haemogram and negative urinary pregnancy test. Exclusion Criteria: * previously suffered an acute major cardiovascular event * those with a chronic disease * those taking chronic medication * those with a history of alcoholism or substance abuse * Ex-smokers * Subjects, who have less than or equal to 60% platelet aggregation in response to arachidonic acid