What’s worse for HIV outcomes: smoking or heavy drinking? The answer might surprise you.

Previous studies showed that heavy drinkers living with HIV were less likely to reach an undetectable viral load. But new research, published in the journal Drug and Alcohol Dependence, found the opposite. Researchers reviewed the medical records of 8,958 people living with HIV who received care at Kaiser Permanente Northern California. They found that smokers were 91% less likely to achieve viral suppression than nonsmokers. No such association between heavy drinking and viral load was found.

The association between smoking and viral load held for everyone who smoked, no matter how often or how long they did so. And while 84% of study participants were engaged in HIV care and 92% had an undetectable viral load during the study period, smokers were 60% less likely to be linked to HIV care in the first place and 30% less likely to stay engaged in care, after adjusting for race, sex and socioeconomic status.