Smoking and alcohol are both vices for people, but there are only treatment facilities to treat addiction for the latter. This doesn’t mean the two are unrelated, though — actually, the opposite is true. A recent study has linked continued smoking to an increased risk of relapse in alcohol treatment.

Most treatments for substance abuse, alcohol included, focus not only on the abuse itself but on surrounding factors that could aid, encourage, or contribute to a person’s substance abuse. Though many of the people with alcohol problems also smoke cigarettes, they have not traditionally been considered in treatment. Asking patients to quit both smoking and drinking at the same time is viewed as too difficult in most clinical settings, and some see smoking as the lesser of two evils when compared to alcohol.

“Quitting smoking will improve anyone’s health,” said study lead author Dr. Renee Goodwin, in a press release. “But our study shows that giving up cigarettes is even more important for adults in recovery from alcohol, since it will help them stay sober.”

The study involved almost 35,000 adults with past alcohol use disorder, who were taken from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). They were tracked and assessed at two different points in time, three years apart, on substance use, substance use disorders, and all related physical and mental disorders.

Researchers found that both daily smokers and non-daily smokers had about twice the odds of having a relapse into alcohol dependence compared with nonsmokers. All other factors, including mood, anxiety, and illicit drug use disorders were controlled for.

The team wasn’t sure why exactly smoking makes alcohol relapse more likely, but the study mentions past research looking at behavioral and neurochemical relationships between smoking and alcohol, and on the negative cognitive effects smoking has.

Source: Goodwin R, Weinberger A, Platt J, Jiang B. “Cigarette Smoking And Risk Of Alcohol Use Relapse Among Adults In Recovery From Alcohol Use Disorders.” Alcoholism: Clinical And Experimental Research. 2015.