Among people who carry HIV, those who smoke have poorer health than those who do not smoke.
definition
The human immunodeficiency virus (HIV) is the virus that causes AIDS (acquired immunodeficiency syndrome).
explanation
People who are HIV-positive are at risk of getting a variety of unusual infections, called opportunistic infections. Some of these infections occur more often in HIV-positive people who smoke than in HIV-positive people who don't smoke. This is particularly true for infections of the mouth. Smoking increases the risk of three types of mouth infections common among HIV-positive people: oral warts, thrush (a fungal infection that can make eating and swallowing difficult), and hairy leukoplakia (a viral infection that causes white sores on the tongue). Smoking also increases an HIV-positive person's risk of getting warts on the sex organs.
People who are HIV-positive have a high risk of catching bacterial pneumonia. Smoking further increases this risk because it impairs the immune system and damages the lungs.
The combination of smoking and HIV also greatly increases a person's risk of heart disease. This interaction doesn't involve the immune system, though. Instead, the problem is that some of the medications used to treat HIV infection increase blood cholesterol levels -- a situation that is especially undesirable in people who have other risk factors for heart disease, such as smoking.
