Much of the increased risk of lung cancer associated with HIV can be explained by a previous diagnosis of AIDS-related pneumonia, aidsmap reports. Publishing their findings in the journal AIDS, researchers compared lung cancer statistics among participants in two longitudinal cohort studies of people living with HIV: the Multicenter AIDS Cohort Study (MACS, including 4,274 men), and the Women’s Interagency HIV Study (WIHS, including 2,549 women). Both studies had HIV-negative comparison groups.

Forty-six people with HIV and 14 HIV-negative participants developed lung cancer during the two studies. All of these individuals were smokers.

The incidence of lung cancer per 100,000 people was 151.8 among women, 50.7 among men, 119 among people with HIV, and 45 among HIV-negative individuals.

When analyzing the two cohorts separately, the researchers did not find that HIV was significantly associated with an increased risk of lung cancer. But combining the cohorts showed that HIV was linked to a 2.64-fold increased risk of lung cancer.

After combining the cohorts and controlling for various factors, the investigators found that variables independently associated with lung cancer included being older, having less education and the level of cigarette use. About two-thirds of the increased risk of lung cancer resulting from having HIV was explained by a previous diagnosis of AIDS-related pneumonia .

Having ever had a CD4 count below 200 was associated with a 2.55-fold greater risk of dying from lung cancer when compared with those who had always maintained CD4s at 200 or above.

To read the aidsmap article, click here.

To read the study abstract, click here.