Low Melatonin Linked to Diabetes

Melatonin is a hormone most commonly linked to sleep and the body's biological clock; melatonin receptors are found throughout the body, including in the islet cells of the pancreas, which produce insulin. Previous studies suggest that loss-of-function mutations in the melatonin receptor are associated with insulin resistance and type 2 diabetes. Claran McMullan, from Harvard School of Public Health (Massachusetts, USA), and colleagues  reviewed data from the U.S. Nurses' Health Study. The researchers found 370 women who developed type 2 diabetes during the study period, from 2000 to 2012. They also selected 370 women without diabetes for comparison. Melatonin levels were obtained through urine samples. When researchers compared women with the lowest levels of melatonin to those with the highest, they found that low levels increased the risk of developing type 2 diabetes by 2.17 times.  This association held true even after the researchers controlled for other risk factors for type 2 diabetes, such as body weight and dietary habits. Writing that: “Lower melatonin secretion was independently associated with a higher risk of developing type 2 diabetes,” the study authors submit that: “Further research is warranted to assess if melatonin secretion is a modifiable risk factor for diabetes within the general population.”