Cigarette smoking as a risk factor or an exacerbating factor for restless legs syndrome and sleep bruxism.

Cigarette smoking has been associated with sleep disturbances. However, little is known about how smoking affects restless legs syndrome (RLS) and sleep bruxism, two movement disorders associated with sleep. From a nationwide survey of 2,019 Canadian adults, we estimated the prevalence of smoking to be 36%. Although there was no difference between smokers and nonsmokers for RLS prevalence, almost twice as many smokers (12%) as nonsmokers (7%) were aware of experiencing sleep bruxism. The estimated risk of a smoker suffering from RLS was nonsignificant. On the other hand, the risk of a smoker grinding his or her teeth was moderate (odds ratio = 1.9). Analysis of sleep laboratory findings revealed no differences in motor RLS and periodic leg movements in sleep (PLMS) indices between smoking and nonsmoking patients; after adjustment for age, there were no differences in sleep efficiency, latency, number of awakenings, or the arousal index for the RLS/PLMS patients. Among those suffering from bruxism, smokers had more tooth-grinding episodes than did nonsmokers (35.0 vs. 7.0; p = 0.056); none of the sleep variables differentiated sleep bruxism smokers from nonsmokers. It appears that cigarette smoking does not influence RLS/PLMS, whereas the risk that smoking and tooth grinding are concomitant is moderate. Smoking was not significantly associated with more motor activity in RLS/PLMS, but more grinding was noted in sleep bruxism.