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Circadian rhythm amplification in diabetic retinopathy: a pilot study

Reutrakul S, McAnany JJ, Park JC, Cross A, Danielson KK, Van Cauter E, Hanlon EC, Law J et al.

Sleep advances : a journal of the Sleep Research Society, 2026

Abstract

Study objectives: Data suggested that diabetic retinopathy (DR) may be associated with a dysregulated melatonin rhythm and disturbed sleep. This pilot study explored the effects of a novel behavioral intervention "Amplify-RHYTHM" in type 2 diabetes (T2D) with DR.

Materials and methods: Eight T2D persons (5M/3F, mean age 57.2 years) with DR participated in a 6-week "Amplify-RHYTHM" intervention, consisting of sleep stability (remote weekly coaching and educational content), and timed light exposure (morning bright light exposure, evening blue light reduction, and nightly light-blocking sleep mask). Data were collected before and after the intervention. Primary outcomes were insomnia symptoms and 14-day actigraphy-derived sleep parameters. Circadian-related parameters included rest-activity rhythm parameters, dim light melatonin onset (n = 5), and overnight urinary 6-sulfatoxymelatonin. Cardiometabolic parameters included glucose levels from a 14-day continuous glucose monitor, high sensitivity C-reactive protein, resting blood pressure, and heart rate. Statistical analysis was performed using paired t-tests or Wilcoxon signed rank tests.

Results: Compared to baseline, after Amplify-RHYTHM intervention, insomnia symptoms significantly decreased (p = .041), variability of sleep midpoint reduced (0.90 [0.27] vs. 1.33 [0.39] h, p = .018), and intradaily variability decreased (0.82 [0.13] vs. 0.95 [0.21], p = .049). Urinary 6-sulfatoxymelatonin remained low and the dim light…

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Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.

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