Deaths from AIDS have declined dramatically since the introduction of highly active antiretroviral therapy in HIV infected patients. However the incidence of heart disease has increased four-fold and is now one of the major causes of death in HIV infected patients. While HIV drugs are known to adversely affect serum lipids, the evidence concerning the association between raised blood pressure (a major risk for cardiovascular disease) HIV and/or its treatment is limited and conflicting. The researchers believe it of interest to study heart disease risk factors in patients with HIV infection to avoid one premature cause of death (AIDS) being replaced with another potentially preventable cause of death and disability (heart disease). In this cross sectional observational study the researchers will systematically measure blood pressure and other cardiovascular risk factors in HIV positive patients on and off antiretroviral therapy. These individuals will be matched for age, sex and ethnic group with HIV negative individuals.