Cigarette smoking, not HIV disease–specific factors, is the most important risk factor for lung cancer in people living with HIV, according to a new paper in the British Journal of Cancer reported by aidsmap.

The new study involving 68 Swiss HIV-positive people with lung cancer, compared with 337 demographic-matched controls, calls into question the results of other papers suggesting that histories of low CD4 cell counts, uncontrolled viral loads and AIDS-related lung disease are also major risk factors for lung cancer.

According to the aidsmap review of the data, 85 percent of the lung cancer patients were current smokers, whereas 6 percent were former smokers, confirming the high prevalence of smoking and its strong association with lung cancer.

Roughly 80 percent of the patients with cancer were men, and their average age at cancer diagnosis was 50. Survival, unfortunately, was poor—only 14 percent, aidsmap reports, were still alive two years after their lung cancer diagnosis.

The strongest associated risk between smoking and lung cancer was among current smokers, who faced a 14-fold increase in the risk of the disease compared with nonsmokers. Former smokers had a significantly lower risk of lung cancer compared with current smokers.

There was no evidence that an AIDS diagnosis with or without pulmonary involvement was associated with lung cancer, the aidsmap report notes. Similarly, neither a history of immune deficiency nor a limited use of antiretroviral therapy was found to increase the risk of lung cancer.

“Our carefully matched case-controlled study…suggests no evidence for a significant effect of HIV-related immunodeficiency on lung cancer risk in this high-risk population,” the investigators wrote. “None of the classic markers or HIV-related immunodeficiency, including low CD4 cell counts, high viral load nor history of AIDS or AIDS-related pulmonary disease, showed any clear association with lung cancer.”