Unhealthy sleep, whether it is too short or too long, is associated with a higher risk of type 2 diabetes in a racially and economically diverse population of adults. The research team, composed of international experts, published these findings. Previous research has already linked poor sleep duration with an increased risk of diabetes, but the new study, published in the journal Diabetologia, extends these findings to a larger group of low-income, older, and middle-aged adults from the southeastern United States.

The study highlighted the importance of sleep health in middle age, especially maintaining a regular sleep schedule to reduce the risk of cardiometabolic diseases. Kelsie Full, PhD, MPH, an epidemiologist and associate professor of medicine at Vanderbilt University Medical Center, emphasized the importance of new information supporting this conclusion.

The study was conducted by Full and her colleague Loren Lipworth, ScD, along with lead author Qian Xiao, PhD, MPH, from the University of Texas Health Science Center at Houston, and Martin Rutter, MD, professor of cardiometabolic medicine at the University of Manchester, United Kingdom.

By definition, non-optimal sleep duration refers to sleeping less than seven hours or more than nine hours per night. Previous research has shown that black adults are more likely to experience long-term unhealthy sleep patterns and a higher risk of diabetes compared to white adults. Additionally, low-income individuals are more prone to poor sleep and the development of diabetes.

The research was based on questionnaires completed by about 36,000 adult participants in the Southern Community Cohort Study, which monitors the health of a racially and economically diverse group of people in 12 southeastern states. Most participants were recruited through community health centers.

Abnormally long sleep may not directly cause diabetes, but it can be an indicator of other risk factors for diabetes, including diabetes-related fatigue. Unlike earlier studies conducted mainly in white or Chinese populations with a single sleep measurement, about 62% of participants in this study were black, and their sleep duration was recorded in two separate questionnaires, five years apart.

One of the main advantages of this study is focusing on long-term sleep patterns rather than single measurements, said Xiao. Moreover, the study was conducted in a large group of predominantly poor and black populations that have traditionally been under-researched in health studies.

The greatest association with diabetes was found among participants who reported extreme changes and greater variability in sleep duration. Highly variable sleep patterns are associated with poorer blood glucose control, obesity, and diabetes. The current results suggest that variable sleep duration in vulnerable populations may be a significant factor contributing to racial and socioeconomic disparities in cardiometabolic health.

Although long sleep may not directly cause diabetes, it can indicate the presence of other risk factors for diabetes, including diabetes-related fatigue. Long sleep remains an important predictor of diabetes risk that can be used for disease prediction and screening. The authors recommended further research to identify social and environmental factors, such as living in stressful, deprived neighborhoods, that can disrupt normal, healthy sleep and how sleep disruption can contribute to racial and socioeconomic disparities in health outcomes.

Interventional studies are also needed to assess whether improving sleep health can reduce health disparities in the US. The study was partially supported by the National Institutes of Health (NIH) through grants R21HL165369 and R01AG063946, and the NIHR Manchester Biomedical Research Centre. The Southern Community Cohort Study is supported by the National Cancer Institute of the NIH.

The study found that sleep regularity is key to reducing the risk of cardiometabolic diseases. Kelsie Full, PhD, MPH, an epidemiologist and associate professor of medicine at Vanderbilt University Medical Center, stated that the research provides new information supporting the importance of sleep health in middle age. It is important to maintain a regular sleep schedule over time to reduce the risk of harmful cardiometabolic conditions. This information is crucial for understanding the connection between sleep and health.

The research was conducted in a large cohort that includes predominantly poor and black populations. These groups have traditionally been under-researched in health studies. The research results suggest that variable sleep duration may be a significant factor contributing to racial and socioeconomic disparities in cardiometabolic health. Long sleep remains an important predictor of diabetes risk and can be used for disease prediction and screening.

Further research should focus on identifying social and environmental factors that can disrupt normal sleep, such as living in stressful and deprived neighborhoods. Sleep disruption can contribute to racial and socioeconomic disparities in health outcomes. Interventional studies are also needed to assess whether improving sleep health can reduce health disparities in the US.

The study was partially supported by the National Institutes of Health (NIH) through grants R21HL165369 and R01AG063946, and the NIHR Manchester Biomedical Research Centre. The Southern Community Cohort Study is supported by the National Cancer Institute of the NIH.

Source: Vanderbilt University Medical Center