"We need to find ways to limit the adverse health implications for night shift workers so they can continue in their roles whilst protecting their long-term health."

To investigate the impact of melatonin, 24 night shift workers and 12 healthy non-shift workers were recruited and underwent glucose tolerance testing and blood pressure monitoring for 24 hours. Night shift workers were then randomised to receive oral melatonin (2 mg) or a placebo at night time or in the morning, depending on their shift schedule, for 12 weeks.

The authors identified that night shift workers were significantly more insulin-resistant than non-night shift workers. After 12 weeks of taking the hormone melatonin, no significant effect was observed in serum glucose or insulin concentrations, which are markers of insulin resistance. Similarly, for blood pressure, treatment with melatonin had no significant effect.

Unsurprisingly, melatonin significantly improved the sleep quality of night shift workers. During the initial assessment, only 21 per cent of night shift workers described their sleep quality as good; however, after 12 weeks of melatonin treatment, 50 per cent of this cohort indicated good sleep quality. The proportion of good versus poor sleepers remained almost unchanged in the placebo group.

Professor Skene added:

"The benefits of improved sleep for shift workers via melatonin are undeniable, and people should feel more rested and alert. However, since there is no evidence that the use of melatonin reduces insulin resistance, we need to find alternate ways to improve insulin resistance and lessen the likelihood of a person developing type 2 diabetes."

This study was published in the journal Pharmacological Research