Effect of Bedtime Melatonin Administration in Patients With Type 2 Diabetes: A Triple-Blind, Placebo-Controlled, Randomized Trial

Document Type: Research article

Authors

1 Department Of Clinical Pharmacy, School Of Pharmacy, Shahid Beheshti University Of Medical Sciences, Tehran, Iran.

2 Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

3 Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences

4 Internal Medicine Department, Endocrinology Division, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

5 Food Safety Research Center, Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

6 Department of Clinical Pharmacy, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

7 Department of Çlinical Pharmacy, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Abstract

Melatonin is widely available as over the counter product. Despite promising effects of melatonin supplementation on glycemic control, there is a significant heterogeneity between studies. The current study aimed at determining the effect of melatonin on fasting blood glucose (FBG), insulin resistance/sensitivity indices, glycosylated hemoglobin A1c (HbA1c), and high sensitivity C-reactive protein (hs-CRP) among type 2 diabetes mellitus (T2D) population during 8 weeks in a randomized, triple-blind, placebo-controlled trial. Thirty four subjects with the mean age ± standard deviation of 57.74 ± 8.57 years and 36 subjects with the mean age of 57.61 ± 9.11 years were allocated to 6 mg nightly melatonin and placebo groups, respectively. Melatonin and placebo groups were matched by age, gender, body mass index, and duration of diabetes. Also, there was no significant difference in laboratory findings except for HbA1c, which was lower in the placebo group (7.00±0.89% vs 7.60±1.47%, P=0.042). After trial completion, the increase of serum levels of melatonin was greater in the intervention than the placebo group (3.38±1.33 vs 0.94±1.28 ng/L, P=0.192). Moreover, compared to placebo group, among melatonin users, homeostasis model assessment of insulin resistance (HOMA1-IR) tended to be unfavorable at the end of follow-up [-0.51 (-1.76-0.81) vs. 0.28 (-1.24-1.74), P=0.20]; the similar trend was also shown for insulin sensitivity index (HOMA1-S) [2.33 (-3.59-12.46) vs. -2.33 (-10.61-9.16), P=0.148]. No differences were observed in FBG, HbA1C, and hs-CRP changes between the trial groups. The current study did not support the improving effect of melatonin on glucose homeostasis.

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