Effects of light therapy on sleep and circadian rhythm in older type 2 diabetics living in long-term care facilities: a randomized controlled trial

Front Endocrinol (Lausanne). 2024 Feb 5:15:1307537. doi: 10.3389/fendo.2024.1307537. eCollection 2024.

Abstract

Background: Light influences the secretion of melatonin in the body and regulates circadian rhythms, which play an important role in sleep and mood. The light level of rooms in long-term care facilities is usually far below the threshold required to regulate the body's circadian rhythm, and insufficient light can easily lead to sleep and mood disturbances among older residents in nursing homes. Therefore, the objective of this study was to investigate the effects of light therapy on sleep and circadian rhythm in older adults with type 2 diabetes residing in long-term care facilities.

Methods: This study was a prospective, single-blind, randomized controlled trial. Participants were randomly assigned to either the light therapy (LT) group or the control group and received the intervention for four weeks. Primary outcomes included the Pittsburgh Sleep Quality Index (PSQI) and objective sleep parameters recorded by a sleep monitoring bracelet, Morningness-Eveningness Questionnaire (MEQ). The secondary outcome included glycated serum protein (GSP). Data was collected at three time points: at baseline (T0), immediate post-treatment (T1), and 4-week follow-up (T2). A linear mixed model analysis was used to analyzed the data.

Results: We enrolled 45 long-term care residents. Compared with the control group, significant reductions in PSQI scores were observed at T1 and T2. At T2, the sleep score of objective sleep parameters was significantly higher in the LT group compared to the control group. Additionally, compared to the baseline T0, MEQ scores were significantly lower in the LT group at T1 and T2, with no significant difference in the control group. There was no significant difference between groups in glycated serum protein values at T1 and T2. However, compared to T0, glycated serum protein values decreased in the LT group while increased in the control group at T2.

Conclusion: Light therapy had a positive effect on subjective sleep quality and circadian rhythm time type in long-term care residents with type 2 diabetes, and had a possible delayed effect on objective sleep. However, no discernible alterations in blood glucose levels were detected in this study.

Keywords: circadian rhythm; light therapy; long-term care facility; older adults; sleep disturbance; type 2 diabetes.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Circadian Rhythm / physiology
  • Diabetes Mellitus, Type 2* / complications
  • Diabetes Mellitus, Type 2* / therapy
  • Glycated Serum Proteins
  • Humans
  • Long-Term Care
  • Phototherapy
  • Prospective Studies
  • Single-Blind Method
  • Sleep / physiology

Substances

  • Glycated Serum Proteins

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The study was reviewed and approved for funding by the Health Humanities Research Center Project, a Key Research Base of Philosophy and Social Sciences in Zigong City (JKRWY23-17); the Nursing Key Laboratory of Sichuan Province (HLKF2022-4), 2022 Open Project of Development and Regeneration key Lab of Sichuan Province (2022LHZYYB-17), the 2022 Open Project of Clinical Research Center for Geriatric Diseases(2022LHFSSYB-03), the Science and Technology Research Special Project of Sichuan Provincial Administration of Traditional Chinese Medicine (2023MS262), the 2022 Chengdu Medical College Graduate Student Innovation Fund (YCX2022-01-43), and the 2022 Chengdu Medical College Graduate Student Innovation Fund (YCX2022-01-48).