Melatonin improves sleep but fails to impact increased insulin resistance in night shift workers

A recent randomized, placebo-controlled study aimed to assess the impact of melatonin administration on glucose tolerance, insulin resistance, sleep quality, and circadian profiles in rotating night shift workers. The findings shed light on the role of melatonin in enhancing sleep quality but indicate limited effects on insulin resistance in this specific group. This study was published in Pharmacological Research journal by Hannemann J. and colleagues.

The study, conducted over 12 weeks with a subsequent 12-week wash-out period, enrolled 24 rotating night shift workers who received 2 mg of sustained-release melatonin or placebo. A unique aspect of this trial was the timing of melatonin administration, aligning with the participants' shift schedules, either at night or in the morning. Researchers compared these night shift (NS) workers with 12 healthy non-night shift (NNS) controls to evaluate baseline profiles.

At the outset, the night shift workers displayed impaired indices of insulin resistance compared to non-night shift workers (p < 0.05). Interestingly, there were no differences noted in oral glucose tolerance tests or in the diurnal profiles of melatonin, cortisol, or blood pressure between the two groups. However, sleep quality was significantly impaired in night shift workers compared to non-night shift workers at baseline (p < 0.001).

Despite the promising improvement in sleep quality observed with melatonin administration, which was significantly impaired in night shift workers initially, the 12-week treatment did not yield significant improvements in insulin resistance. Furthermore, melatonin did not significantly impact diurnal blood pressure or the profiles of melatonin and cortisol among the night shift workers.

Researchers highlighted the study's important findings. While melatonin administration notably improved sleep quality in rotating night shift workers, it did not lead to significant improvements in insulin resistance after the 12-week treatment.

These results indicate the complexities of addressing the challenges faced by night shift workers, emphasizing the need for further research into interventions that effectively mitigate the adverse metabolic effects associated with shift work.

Reference:

Hannemann, J., Laing, A., Middleton, B., Schwedhelm, E., Marx, N., Federici, M., Kastner, M., Skene, D. J., & Böger, R. Effect of oral melatonin treatment on insulin resistance and diurnal blood pressure variability in night shift workers. A double-blind, randomized, placebo-controlled study. Pharmacological Research: The Official Journal of the Italian Pharmacological Society,2024;199(107011):107011. https://doi.org/10.1016/j.phrs.2023.107011