Sleep bruxism - genetic factors and psychoactive substances : Studies in Finnish twins
Year: 2014
Type: dissertation
Study design: Observational Study
Abstract: Background: Genetic and environmental factors have a varying influence on oral health-related problems. Although studies have been conducted, the contribution of genetic factors to sleep-related bruxism remains obscure. Bruxism causes several physical problems, including abnormal tooth wear, pain in the temporomandibular joint or jaw muscles, and headaches, as well as social problems. The detailed aetiology of bruxism is unknown. In addition to genetic factors, psychoactive substances are considered to be potential risk factors for bruxism. Aims: The aim of the present study was to explore the role of genetic and environmental factors in the phenotypic variance of self-reported sleep-related bruxism. A second aim was to investigate the potentially independent roles of three commonly used legal psychoactive substances, tobacco, alcohol, and coffee, in the occurrence of self-reported sleep-related bruxism. Subjects: The study was based on two large twin cohorts, one of young adults and the other of middle-aged twins. The data of young adult twins were derived from the fourth wave of the longitudinal FinnTwin16 cohort study consisting of twins born in 1975-1979. The participants (n=3124 subjects, mean age 24 years) completed a questionnaire in 2000-2002 enquiring about the, the occurrence of sleep-related bruxism in young adults and the use of tobacco products. The data of middle-aged adult twins derived from the Finnish Twin Cohort study consisting of twins born in 1930¬-1957. The participants (n=12 502 subjects, mean age 44 years) completed a questionnaire in 1990 enquiring about sleep-related bruxism and the use of psychoactive substances, tobacco products, alcohol, and coffee. Methods: Quantitative genetic modelling was based on the genetic similarity of monozygotic and dizygotic twins and on the decomposition of phenotypic variance into the following components: additive genetic effects (A), dominant genetic effects (D), and non-shared environmental effects (E). Quantitative genetic modelling was used to evaluate the relative proportion of genetic factors of the phenotypic variance in the liability to bruxism. Multinomial logistic regression was used to explore the association between bruxism and psychoactive substances as independent risk factors. Results: The models revealed a clear genetic component behind bruxism. The best fitting genetic model for bruxism was the AE-model in which additive genetic effects accounted for 52% of the total phenotypic variance with no gender differences. The three legal psychoactive substances (tobacco, alcohol, and coffee) were clearly associated with bruxism. In addition, all of them raised the odds for bruxism independently, and there were no significant interactions between them. Conclusions: Genetic factors contribute to inter-individual differences and account for a substantial proportion of the phenotypic variation of the liability to sleep-related bruxism. Bruxism had no gender difference in their genetic architecture. Psychoactive substances are associated strongly with bruxism, and the relationship is independent of other psychoactive substances, cumulative, and dose-dependent. The twin approach provides evidence of a possible causal link between psychoactive substances and bruxism. Thus, this study consolidates new information about genetic and environmental factors in sleep-related bruxism.
Source: Työväentutkimus Vuosikirja
Author: K. Rintakoski
Language: English
Subfield: Oral Surgery
Field: Dentistry
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1539145975