New research suggests that people with a history of alcohol problems who continue to smoke are at a greater risk of relapsing.

Researchers at Columbia University's Mailman School of Public Health and the City University of New York found that adult smokers with a history of problem drinking who continue smoking are at a greater risk of relapsing three years later compared with adults who do not smoke.

"Quitting smoking will improve anyone's health," Renee Goodwin, lead author of the study and an associate professor in the Department of Epidemiology at the Mailman School of Public Health. "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."

For the study, researchers collected and analyzed data from more than 34,600 people with a past alcohol use disorder enrolled in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) who were assessed at two time points, three years apart, on substance use, substance use disorders, and related physical and mental disorders.

They found that daily smokers and nondaily smokers had approximately twice the odds of relapsing to alcohol dependence compared with nonsmokers. The relationships held even after controlling for factors, including mood, anxiety, illicit drug use disorders, and nicotine dependence.

Researchers said it is unclear why smoking makes alcohol relapse more likely, but the study's authors point to past research on the behavioral and neurochemical links between smoking and alcohol, and the detrimental effects of smoking on cognition.

The findings are detailed in the journal Alcoholism: Clinical and Experimental Research.