Methods: The material derives from the Finnish Twin Cohort study consisting of 12,502 twin individuals (45.6% men, 54.4% women, mean age 44 years) born in 1930¬-1957. Twins responded to a questionnaire in 1990 (response rate of 77%) consisting of 103 multiple choice questions, four dealing with alcohol use, seven with tobacco use and two with perceived bruxism.
Results: Based on subjective responses and multivariate analyses adjusted for age and sex, and for age, sex and smoking status (never, occasional, former, current), those drinking alcohol heavily, i.e. more than 13 bottles beer per week, 3 bottles wine per week, at least 2 bottles of spirits per month, were more than two times more likely report weekly bruxism compared to those drinking no alcohol (OR 2.7 beer, 2.7 wine, 2.3 spirits; 95 % CI 1.61-4.44, 1.02-6.99, 1.59-3.27). The significant association between consumption of beer and spirits with bruxism held when the effect of smoking was controlled while the effect of wine consumption lost statistical significance. Also, binge drinking and passing out due to alcohol raised the risk independently. When the overall consumption was computed as grams of alcohol per day (log-transformed), this was highly significantly associated with bruxism even when adjusted for smoking status.
Conclusions: Given the observed associations with heavy drinking, binge drinking and passing out due to alcohol, the present results support our hypothesis of an independent link between alcohol use and bruxism.