Too much or too little sleep, along with other unhealthy sleep patterns, was found to be associated with a significantly increased risk of type 2 diabetes in a racially and economically diverse population of middle-aged and older Americans. Diabetology The study was conducted by an international research team led by Vanderbilt University Medical Center.
“Our study provides new information supporting the importance of sleep health in midlife, particularly maintaining a regular sleep schedule over time, in reducing the risk of cardiometabolic deterioration,” said Kelsey Full, PhD, MPH, a behavioral epidemiologist and assistant professor of medicine at Vanderbilt University Medical Center.
Unhealthy sleep patterns
Unhealthy/suboptimal sleep duration is defined as sleeping more than 9 hours or less than 7 hours per night. Previous studies have shown that low-income adults are more likely to suffer from poor sleep and develop diabetes. Other studies have also shown that Black adults are more likely to experience long-term unhealthy sleep patterns and a disproportionately higher burden of diabetes.
the study
The study was based on questionnaires from nearly 36,000 adults who took part in the Southern Community Cohort Study, which tracks the health of racially and economically diverse participants in 12 southeastern states recruited through community health centers. Participants’ sleep duration was reported in two separate surveys conducted an average of five years apart.
“One of the major strengths of our study is that we focused on long-term sleep patterns rather than a one-time measurement,” said Xiao, an associate professor of epidemiology, human genetics and environmental sciences at the University of Texas Health Science Center at Houston School of Public Health.
“Furthermore, we conducted our study in a large cohort of primarily low-income and Black people, populations that have traditionally been understudied in health research,” she said. “By focusing on long-term sleep patterns, we demonstrate the importance of maintaining healthy sleep patterns over time for metabolic health.”
What they found
The researchers found that the strongest associations with diabetes were among people who reported extreme changes and large fluctuations in their sleep duration — high sleep variability has previously been linked to poor blood sugar control, obesity and diabetes.
Based on their findings, the researchers concluded that “the wide variation in sleep duration among disadvantaged populations may be an important contributing factor to racial and socioeconomic disparities in cardiometabolic health.”
They also point out that while abnormally long sleep duration does not directly cause diabetes, it may reflect other diabetes risk factors, such as diabetes-related fatigue, and explain that “long sleep duration remains an important behavioral predictor of diabetes risk and may be used for risk prediction and disease screening.”
Further research needed
The team also recommended further research to explore and identify social and environmental factors, such as living in stressful or disadvantaged areas, that may disrupt sleep, and how disrupted sleep may contribute to disparities in health outcomes.
“Intervention studies are also needed to evaluate whether improving sleep health could reduce health disparities in the United States.”
