Tobacco is a legal and widely-used drug, especially among HIV-positive people. In the Futures 5 survey, 47.6 percent of respondents had smoked tobacco in the last 12 months, a figure that is significantly higher than the 23 percent of Australians who smoke. Smoking is highly addictive and its negative health impacts have been well established.

Smoking, by itself, does not make HIV infection worse. In clinical studies, people who smoked tobacco did not do any worse (or better!) than those who didn’t in terms of HIV disease progression. But smoking has been linked to increased rates of some HIV-related opportunistic infections and HIV-positive people who smoke may be more likely to suffer smoking-related diseases than HIV-negative smokers.

Several studies have shown that the AIDS-related pneumonia PCP is more common among people who smoke, and that the risk of dying from PCP is higher in smokers. Positive smokers are also more likely to develop oral hairy leukoplakia, oral candidiasis and community-acquired bacterial pneumonia, compared to non-smokers.

Compared to HIV-negative smokers, HIV-positive smokers have an increased risk of developing emphysema, a debilitating smoking-related illness which prevents adequate oxygen from entering the bloodstream. There is also increasing evidence that the incidence of lung cancer is higher if you’re HIV-positive, regardless of your CD4 count or viral load.

It’s well known that smoking is a major cause of heart and artery disease, high blood pressure, and stroke. Living long-term with HIV, and taking some HIV treatments, are also considered risk factors for the development of these diseases, so it’s likely that HIV- positive people who smoke will have a significantly increased likelihood of developing them as they get older.

THE BOTTOM LINE: Clinical studies have not shown that smoking tobacco worsens HIV directly, but they have shown that positive people who smoke are more likely to develop smoking-related illnesses and some AIDS-related complications. If you’re one of the 47 percent of positive people who smoke, giving up the habit could be the most important health decision you can make.