Men infected with the human immunodeficiency virus (HIV) are more sensitive to the effects of alcohol than uninfected men, according to a recent study.

Researchers at Yale University and VA Pittsburgh Healthcare System compared the number of drinks that men with HIV infection, versus those without it, needed to get a buzz. They found that HIV-infected men with detectable virus were more sensitive to the effects of alcohol than both HIV-infected men with suppressed virus and uninfected men.

HIV and alcohol can make for a dangerous mix, researchers noted.

"Alcohol makes it more likely you're going to get HIV due to risky sexual behavior," Dr. Amy C. Justice, professor of medicine and public health at Yale, said in a statement. "Once people have HIV, alcohol makes it less likely they will take their antiretroviral medications." Drinking, like HIV infection, also harms the liver and immune system.

For the study, researchers collected and analyzed data from more than 2,600 men enrolled in the Veterans Aging Cohort Study, an ongoing multi-site study of veterans. They analyzed survey responses from both HIV-infected and uninfected veterans who were asked how many alcoholic drinks it took for them to feel a buzz or high. The researchers also compared responses from HIV-infected men with unsuppressed or detectable HIV infection versus those with suppressed HIV.

"All else equal, people who have HIV infection have a lower tolerance for alcohol than similar people without HIV infection," Justice explained.

They still don't know whether HIV-infected individuals are simply more susceptible to alcohol or if they achieve higher concentrations of alcohol in the blood from the same number of drinks. It's not exactly clear.

The findings, which are detailed in the journal AIDS and Behavior, suggest that there is no clearly safe level of alcohol consumption for people with HIV.