This article previously appeared in HIV Update, a publication of aidsmap, here.
Numerous studies have shown that rates of cancer are higher in people with HIV than in the general population.
Some of this is to do with the immune damage caused by untreated HIV infection. In fact in the recent large study looking at the best time to start HIV treatment, cancers were one of the most important causes of ill health in people who delayed HIV treatment until their CD4 count dropped to around 350. Beginning HIV treatment promptly strengthens the immune system and protects against cancer.
But another reason for higher cancer rates is unhealthy lifestyles. If – on average – people with HIV smoke, drink and take more drugs than people in the general population, then we can expect cancer rates to be higher.
A group of researchers searched for and pooled the results of 113 studies which collected information on lifestyle and risk factors in people living with HIV. Around half the studies were done in North America and the other half in Western Europe. Two-thirds of the people included in the studies were men and their average age was 44.
This may not be an entirely representative sample but comparisons with figures from the general population of the United States are striking.
Whereas 20 to 23% of the general population are current smokers, 54% of people with HIV are. Similarly, 5 to 15% of the general population are heavy drinkers, compared to 24% of people with HIV.
Although fewer than 1% of the general population have either hepatitis B or C, rates in people with HIV are 5% and 26% respectively. (Hepatitis can lead to liver cancer.)
Human papillomavirus (HPV) can be picked up during sex and can in some cases result in cancer. In the general population, 29% have cervical HPV, compared to 46% of women with HIV. Rates of oral HPV are also strikingly different (4% and 16%). Over two-thirds of gay men with HIV have anal HPV but there isn’t a reliable figure for the wider population.
More encouragingly, the proportion who are overweight or obese is the same or lower than in the general population.
The researchers stress that the risk of cancer can be reduced by lifestyle changes.