Night Shift Workers With Diabetes Tend to Have Poorer Glycemic Control

Research presented this week at the 99th annual meeting of the Endocrine Society suggested that people with type 2 diabetes who worked overnight shifts tend to have poorer control over their blood sugar levels than those who worked during the day or were unemployed.

The study was conducted by researchers in Thailand, who collected data on 260 diabetes patients in that country who either worked the night shift or the day shift or were unemployed. In a press release from the meeting, they explained that prior studies have found night shift workers are at higher risk of developing diabetes, but it remained unclear what kind of effects this type of work schedule could have on glucose outcomes after diagnosis.

"Previously, there were little data whether people who already have type 2 diabetes and work the night shift have trouble controlling their blood sugars," said lead author Sirimon Reutrakul, MD, associate professor at Mahidol University Faculty of Medicine in Bangkok. "Our study data raise awareness of the difficulty in diabetes control among night shift workers."

Over a study period of 3 months, the night shift workers had the highest average hemoglobin A1C levels at 8.2%. The average A1C levels of those who worked during the day or not at all were similar at 7.6% and 7.5%, respectively. The night shift workers tended to consume more calories daily and report a higher body mass index and shorter sleep duration, all risk factors that affect glucose control. However, after adjusting the analyses to account for these variables, the researchers found that the association between work schedule and glycemic control continued to be statistically significant.

As of 2004, nearly 15 million Americans worked full time on evening or night shifts or regularly rotated into such shifts. Numerous studies have assessed the risks of this disruption to the body’s circadian rhythms, from fatigue-related accidents to increased risk of metabolic syndrome, according to the American Psychological Association.

Even if workers cannot control what time they clock in and out, the authors of the glycemic control study said they can take some steps to mitigate the harmful effects of shift work on their health. The entire population of night shift workers may benefit from efforts to reduce the disruptions in the sleep-wake cycle, while patients with diabetes in particular should take additional precautions.

"Diabetic individuals who work at night should pay special attention to managing their disease through healthy eating, regular exercise and optimal use of medications prescribed by their physician," Reutrakul recommended.

The night shift study was not the only research on diabetes and sleep that Reutrakul presented at the Endocrine Society’s meeting. Another study examined diabetes patients in the United States and Thailand and found that those who stayed up later at night were more prone to depression, which can make optimal diabetes management more difficult.

Taken together, the findings of the 2 studies point to the importance of sleep as a key determinant of wellness, particularly for patients attempting to keep their diabetes under control.