Drawing Connections Between Diabetes, Obesity, and Sleep

Brian Wojeck, MD, MPH, researches the interrelated disease processes of diabetes, obesity, and sleep disorders. An assistant professor of medicine (endocrinology and metabolism) and weight management specialist, he first came to Yale School of Medicine to pursue a sleep fellowship before becoming interested in endocrinology.

“Somewhere along the way, I thought, ‘How can I put this together? What is the link between hormones and sleep?’” Wojeck said. He subsequently received training in obesity medicine.

In a Q&A, Wojeck discusses how weight and sleep impact each other and how discovering connections between diabetes, obesity, and sleep disorders can lead to better treatment.

We know that heavier people are at a higher risk of obstructive sleep apnea. One of the pieces of obstructive sleep apnea is upper airway anatomy, and weight can worsen upper airway anatomy and increase collapsibility. We know that increased weight is associated with increased obstructive sleep apnea and often worsening severity.

As people lose weight, apnea tends to improve. Studies in the general population with dietary interventions, bariatric surgery, and novel weight-loss agents have shown that weight loss significantly decreases obstructive sleep apnea. For example, a study showed that patients taking the weight-loss drug tirzepatide had, on average, a 50% reduction in the severity of obstructive sleep apnea after about one year of therapy.

Data shows that sleep deprivation has important effects on our hormones. When people are sleep-deprived, they have increases in hormones like ghrelin and decreases in hormones like leptin, and they get hungrier. These changes in hormone levels can cause people to gain weight.

Part of my research is focused on polysomnographic predictors of type 2 diabetes. For example, I’ve studied which characteristics of sleep apnea are linked to increased incidence of type 2 diabetes and pre-diabetes. We’ve found a correlation between individuals who have more hypopneas—which are sleep disorders marked by shallow breathing—with concurrent low oxygen saturation and the incidence of type 2 diabetes. Oxygen saturation levels alone, which can decrease in people with sleep apnea, also seem predictive.

Obesity is often the starting point of many different disease processes, and each disease impacts the other. We hope to continue developing links between sleep disorders, obesity, and diabetes to better understand mechanisms and find novel therapeutics to address all these interrelated conditions.

Yale School of Medicine’s Section of Endocrinology and Metabolism works to improve the health of individuals with endocrine and metabolic diseases by advancing scientific knowledge, applying new information to patient care, and training the next generation of physicians and scientists to become leaders in the field. To learn more, visit Endocrinology and Metabolism.