Associations between sleep bruxism, sleep quality, and exposure to secondhand smoke in Japanese young adults: a cross-sectional study

Naoki Toyama, Daisuke Ekuni, Ayano Taniguchi-Tabata, Toshiki Yoneda, Kota Kataoka, Aya Yokoi, Yoko Uchida, Daiki Fukuhara, Hikari Saho, Islam Md Monirul, Nanami Sawada, Yukiho Nakashima, Yoshiaki Iwasaki, Manabu Morita

Research output: Contribution to journalArticle


Objective: Sleep bruxism, a major sleep disorder that causes serious harm to oral health, is considered a multifactorial disease. Sleep bruxism can be induced by smoking, which also adversely affects sleep quality. The objective of present study was to clarify the associations between sleep bruxism, sleep quality, and exposure to secondhand smoke (SHS). Methods: To assess the prevalence of sleep bruxism, sleep quality, and SHS exposure, we conducted oral examinations and self-report questionnaires on university students in Japan. Sleep bruxism and quality were screened using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI) and the third edition of the International Classification of Sleep Disorders (ICSD-3). The inclusion criteria were adults aged between 18 and 19 years, non-smokers and non-alcohol drinkers. The exclusion criteria was failing to complete the questionnaire in full. Results: We analyzed a total of 1781 Japanese young adults. Young adult females who had been exposed to SHS had worse sleep quality (p = 0.019) than those who had not. Young adult female with worse sleep quality showed a higher prevalence of sleep bruxism (p = 0.034) than those with better sleep quality. Using structural equation modeling, direct associations were identified between SHS exposure and poor sleep quality (standardized coefficients, 0.153; p = 0.008) and between sleep bruxism and poor sleep quality (standardized coefficients, 0.187; p = 0.022) in young adult females. However, no association was found among young adult males. Conclusion: SHS exposure is indirectly associated with sleep bruxism through poor sleep quality in Japanese young adult females.

Original languageEnglish
Pages (from-to)57-62
Number of pages6
JournalSleep medicine
Publication statusPublished - Apr 2020



  • Cross-sectional study
  • Secondhand smoke
  • Sleep bruxism
  • Sleep quality
  • Young adults

ASJC Scopus subject areas

  • Medicine(all)

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