A176: Meta-Analysis of the Effects of Phototherapy on Sleep QualityAcross Different Populations

Background: Sleep, a fundamental physiological need for humans, significantly impacts an individual's physical and mental health. Phototherapy, a non-pharmacological intervention, has been extensively researched in recent years to improve sleep quality. This study aimed to systematically evaluate the effects of phototherapy on sleep quality across different populations through a meta-analysis, using Pittsburgh Sleep Quality Index as the outcome measure, thereby providing a scientific basis for improving the population health levels and life quality. Method: As of March 1, 2024, this study conducted a systematic search of four databases: Web of Science, PubMed, Embase, and CNKI. A comprehensive set of inclusion and exclusion criteria was established for literature screening, with statistical analysis performed using Review Manager software. Results: From the initial retrieval of 90 articles, 12 were ultimately included in the meta-analysis after systematic screening. The meta-analysis results showed that phototherapy significantly improved short-term sleep quality compared to placebo (MD = -1.39, 95% CI: -2.33 to -0.45, Z = 2.89, I^² = 94%, P = 0.004 < 0.05). However, the improvement in sleep quality was not significant 2-4 weeks after the cessation of phototherapy (MD = -0.48, 95% CI: -2.60 to 1.65, Z = 0.44, I^² = 97%, P = 0.66 > 0.05). Phototherapy significantly improved sleep quality in older adults (MD = -2.70, 95% CI: -3.59 to -2.29, Z = 2.70, I^² = 91%, P < 0.01), but had no significant effect on adolescents and middle-age (MD = -1.67, 95% CI: -4.23 to -0.69, Z = 1.39, I^² = 54%, P = 0.17 > 0.05) and (MD = -0.89, 95% CI: -2.64 to 0.87, Z = 0.99, I^² = 52%, P = 0.32 > 0.05). Additionally, phototherapy significantly improved sleep quality in patients with depression and sleep disorders (MD = -0.32, 95% CI: -0.64 to -0.00, Z = 1.97, I^² = 0%, P = 0.05) and (MD = -1.66, 95% CI: -2.81 to -0.51, Z = 2.82, I^² = 91%, P < 0.01). Discussion: Phototherapy stimulated retinal photoreceptors with specific light intensities and wavelengths, which signaled the Suprachiasmatic Nucleus (SCN) to adjust the internal biological clock, affecting the sleep-wake cycle. Blue light suppressed melatonin production during the day, enhancing alertness, while red light promotes melatonin secretion at night, aiding sleep. This study, despite variability and heterogeneity across different experiments, provides a scientific basis for improving sleep quality.