European researchers say past or present smoking is a "major contributor" to the common problem, which affects up to 33% of men and 19% of women.
Karl Franklin, MD, PhD, of the respiratory medicine department at University Hospital in Umeå, Sweden, worked with colleagues on the study. It's one of only a handful addressing tobacco smoke and snoring.
They evaluated questionnaires from more than 15,000 men and women aged 25-54 in Iceland, Estonia, Denmark, Norway, and Sweden. The study appears in the October issue of the American Journal of Respiratory and Critical Care Medicine.
Habitual snoring, defined as loud and disturbing snoring at least three nights per week, affected 24% of smokers, 20% of ex-smokers, and almost 14% of people who had never smoked.
The more people smoked, the more frequently they snored.
Even nonsmokers were more likely to snore if they were exposed to secondhand smoke in their homes.
Almost 20% of these nonsmokers snored, compared with nearly 13% who had never been exposed to secondhand smoke at home.
And although more men tend to snore, female smokers were slightly more likely to snore than male smokers.
There are several explanations about smoking's impact on snoring, say the researchers.
One theory says smoking irritates and inflames the upper airways, making snoring more likely. Another suggests that smokers with overnight nicotine withdrawal have more sleep instability, raising the risk of upper airway obstruction.
Alcohol, which was not addressed in this study, could also be a factor.
"It is likely that smokers drink more than others, and snoring is probably induced or worsened under the influence of alcohol," say the researchers.