Irregular Sleep May Lead to 35% Higher Diabetes Risk, According to a New Study

We have previously reported on the link between circadian rhythms, which are influenced by our sleep and wake cycles (and vice versa), and health. When our circadian rhythms are out of sync with no consistent flow, it throws processes in our bodies out of whack, increases inflammation and may increase our risk of disease, including heart disease, high blood pressure and obesity. 

But what about diabetes? While there is evidence that inconsistent sleep and circadian rhythms may increase the chances of diabetes, a new study published on July 17, 2024, in Diabetes Care set out to see how strong the connection is, and whether having a genetic propensity toward diabetes would increase this risk. Let’s see what they found.

How Was This Study Conducted & What Did It Find?

Participants were all a part of the UK Biobank, a large, ongoing community-based cohort study in the United Kingdom. Researchers chose 84,421 participants with the necessary information and demographics needed for the study from the over 500,000 people in the Biobank. At the time of enrollment (2006-2010) into the Biobank, participants were 40 to 69 years old and free of diabetes. About 57% of them were female. 

Participants provided information about demographics, lifestyle and family medical history. They also provided blood samples and physical measurements (height, weight, waist circumference, etc.). Researchers had access to participants’ medical records, as well.

During enrollment into the Biobank, participants wore a waterproof accelerometer on their dominant wrist for seven days. The accelerometer recorded movement and sleep duration so that researchers could determine how long participants slept and how consistent they were with their sleep patterns. 

In addition, each participant was tested for specific genes that tend to predispose people to diabetes. One of the hypotheses researchers were testing for with this study was whether those with a higher genetic risk for diabetes would be more adversely affected by irregular sleep patterns, placing them at an even higher risk for diabetes. 

Participants were followed for an average of 7.5 years. During that time, 2,058 participants developed diabetes. 

After statistical analyses were run, the results were in. Before adjusting for certain confounders, those with irregular sleep patterns had a 35% higher risk of diabetes compared to those with more consistent sleep patterns. After taking into account and adjusting for certain medical conditions and adiposity (body fat, particularly in the abdominal region), the risk decreased to 11% but the link remained strong.

What was surprising was that when sleep patterns were inconsistent, it was not those with a higher genetic tendency for diabetes that were at higher risk for it. In this study, the data suggested that it was those with lower genetic risk for diabetes.

The association between inconsistent sleep patterns and diabetes was also greater in those who tended to average more than the recommended amount of sleep—in this case, more than eight hours a night.

They also found that when the sleep inconsistencies averaged an hour or more a night, this also placed participants at higher risk for diabetes. This can be complicated to explain, but basically, let’s say that in a week, you get anywhere from 9 to 10 hours of sleep a night. Because that is more sleep than is recommended and because it varies an hour per night, that inconsistency, especially when your average sleep time is more than recommended, may place you at higher risk for diabetes. 

How Does This Apply to Real Life?

Researchers gave several possible reasons why longer and inconsistent sleep patterns seem to be associated with a higher risk of diabetes. First, they say that sleeping longer than is recommended decreases the amount of daylight exposure, which can throw off circadian rhythms. Irregular sleep patterns also disrupt circadian rhythms, so those who are inconsistent with their sleep and sleep longer than is recommended are in a double-whammy sort of situation. 

They also explain that the circadian timing system in our bodies coordinates certain metabolic processes, like insulin secretion and glucose metabolism. When the circadian rhythms are thrown off, it could lead to reduced insulin sensitivity and disrupted glucose metabolism, which can place you at higher risk for diabetes and other related cardiometabolic diseases—like heart disease. 

When we’re not getting enough sleep or when our sleep patterns are inconsistent, it can also disrupt our eating patterns, as well as cause inflammation and gut dysbiosis (an unfavorable ratio of beneficial to harmful gut bacteria). 

So, what do your sleep patterns look like? Are you getting too little or too much? Are you consistent with the amount of sleep you average each night? 

You can work to improve your sleep patterns by establishing a bedtime routine that includes shutting down your devices, dimming lights and allowing your brain to relax and your body to prepare for sleep. Alcohol and an unhealthy gut microbiome can disrupt sleep, as can eating too close to bedtime—so being consistent with eating patterns earlier in the day can help sleep patterns at night. And make sure you’re eating gut-friendly foods to help your microbiome thrive. This includes fiber-rich plant-based foods that will feed your beneficial bacteria, as well as fermented foods, like yogurt and kimchi, which will add probiotics (beneficial bacteria) to your gut. 

If you feel like you’re getting the right amount of sleep but are still exhausted, this might be a sign of a sleep disorder, like sleep apnea. Sleep apnea can affect your heart, so it’s important to talk to your health care practitioner about it. 

The Bottom Line

This study adds to the growing body of research that shows how inconsistent sleep patterns affect many other aspects of our lives, including increasing inflammation levels in our bodies and our risk of disease. Specifically, it suggests that inconsistent sleep patterns plus getting more than the recommended amount of sleep increases the risk of developing diabetes compared to those with more consistent sleep patterns who average around eight hours of sleep a night. It’s important to recognize the importance of sleep and make it a priority for your overall good health.