GENETIC AND ENVIRONMENTAL FACTORS INVOLVED IN SLEEP BRUXISM

目的是揭示遗传和环境因素在睡眠磨牙症中的重要性。这些双胞胎是通过大阪大学医学研究生院双胞胎研究中心从日本双胞胎母亲俱乐部招募的。研究对象为84对双胞胎（42对，平均年龄22.3±6.8岁）。用便携式自动睡眠磨牙分析仪记录左颞肌夜间肌电活动总数。这些录音连续进行了三个晚上。基于结构方程模型进行了定量遗传统计。协方差结构分析结果表明，加性遗传效应为0.42，独特环境效应为0.58。根据本研究的结果，遗传因素可以被认为是诱发睡眠磨牙症的重要因素。然而，估计的环境影响为0.58，表明对睡眠磨牙症患者进行个体评估的重要性。

The objective was to reveal the importance of genetic and environmental factors involved in sleep bruxism. Twins were recruited from the Twin Mothers Club Japan through the Twin Research Center, Osaka University Graduate School of Medicine. Subjects consisted of 84 twins (42 twin pairs, mean age = 22.3± 6.8 yrs.). The total numbers of nocturnal electromyographic activities of the left temporal muscle were recorded with a portable automatic sleep bruxism analyzer. The recordings were carried out for three consecutive nights. The quantitative genetic statistics based on the structural equation modeling was carried out. The result of covariance structure analysis showed that the additive genetic effect was 0.42 and the unique environmental effect was 0.58. According to the result obtained from the present study genetic factors could be considered as a significant contributing factor for the initiation of sleep bruxism. However, the estimated environmental effect at 0.58 suggests the importance of individual evaluation of patients with sleep bruxism.