Orthopaedic HTC is participating in a study examining cardiovascular disease in hemophilia. We are one of 15 centers nationwide collecting data for this project. This research is sponsored by ATHN and funded by the Centers for Disease Control. The study involves collecting blood samples for cholesterol, lipids and other tests from severe or moderate hemophilia A or B patients between the ages of 54-73 years old and a conducting a review of their medical history. The objective of this study is to determine how many men with severe hemophilia A or B in this age group have heart disease, a past stroke, or other symptoms of atherosclerosis (hardening of the arteries) and to obtain a better understanding of the similarities and differences in risk factors for cardiovascular disease (heart disease, stroke and atherosclerosis) between men with hemophilia and a group of US men of similar age without hemophilia.