Irregular sleep patterns increase risk of type 2 diabetes

Irregular sleep patterns are associated with an increased risk of diabetes in middle-aged and older people, according to a new study from UK Biobank.

An analysis of more than 84,000 participants with seven days of acceleration data suggested that those with the most irregular sleep patterns had a 34% higher risk of diabetes compared to those with more consistent sleep patterns.

“It's recommended that we get seven to nine hours of sleep each night, but policy guidelines and clinical levels don't really take into account how often we need to get that,” said Dr. Sina Chianese of Brigham and Women's Hospital in Boston. Medscape Medical News“Our study shows that it's not just the length of time that we sleep that matters, but also the consistency of our sleep. Patients can reduce their risk of diabetes by maintaining seven to nine hours of sleep, not just overnight, but across their lifetime.”

This study Publish online in Diabetes Care.

Lifestyle elements can be changed

Researchers analyzed data from 84,421 UK Biobank participants who were free of diabetes when they provided accelerometer data between 2013 and 2015. Participants were followed for an average of 7.5 years (622,080 person-years).

The mean age of participants was 62 years, 57% were female, 97% were white, and 50% worked non-shift jobs.

Variability in sleep duration was quantified by the within-person standard deviation (SD) of accelerometer-measured sleep duration across 7 nights.

Participants with a higher SD of sleep duration were younger, more likely to be female, shift workers, and smokers, and less likely to report a clear “evening” chronotype (the body's natural preference for sleeping at a particular time), have lower socioeconomic status, have a higher BMI, have shorter average sleep duration, and be white.

Additionally, family history of diabetes and depression was more common among these participants.

A total of 2058 incident cases of diabetes occurred during the follow-up period.

After adjusting for age, sex, and race, compared with sleep duration SD ≤ 30 min, hazard ratios (HRs) were 1.15 for 31–45 min, 1.28 for 46–60 min, 1.54 for 61–90 min, and 1.59 for ≥ 91 min.

After initial adjustment, diabetes risk was 34% higher in those with a sleep duration >60 min SD compared with ≤60 min SD, but after further adjustment for lifestyle, comorbidities, environmental factors, and obesity, the association weakened to an HR of 1.11 comparing those with a sleep duration >60 min SD compared with ≤60 min SD.

Furthermore, the researchers found that the association between sleep duration and diabetes was stronger in people with lower diabetes polygenic risk scores.

“One explanation for this finding could be that the effect of sleep irregularities on diabetes risk may be less pronounced in people with a strong genetic predisposition, i.e. in those in whom genetic factors are dominant,” Chianese said. “However, it should be noted that the effect of sleep-gene interactions was not consistently observed across different measures and gene-related variables. This needs to be further explored.”

But, he added, “we want to emphasize that the association between irregular sleep duration and increased diabetes risk was evident across all levels of the diabetes polygenic risk score.”

The association was stronger with longer sleep duration, which the authors suggested “may reduce exposure to sunlight, which may lead to circadian disruption.”

Overall, Kianelesi said, “our study has identified modifiable lifestyle factors that may help lower the risk of developing type 2 diabetes.”

This study had several limitations. There was an average 5-year time lag between sleep duration measurement and covariate assessment, which may introduce bias into lifestyle behaviors that may change over time. Furthermore, a single measurement of sleep duration over a 7-day period may not capture long-term sleep patterns. A constrained random sampling method was used to select participants, which may introduce selection bias.

Regular sleep habits are best

Anna Krieger, MD, MPH, director of the Center for Sleep Medicine at Weill Cornell Medicine in New York City, commented on the study: Medscape Medical News“This is a very interesting study that adds new information to the literature,” she said, “Previous studies have shown metabolic abnormalities associated with sleep duration and fluctuations in sleep time.”

“This particular study evaluated a large sample of predominantly middle-aged, white, UK patients and may not be representative of the general population,” she noted. Similar studies “In the Hispanic/Latino group, no significant association was found between sleep variability and diabetes incidence. It would be desirable to see prospective studies demonstrating whether implementing more regular sleep habits reduces diabetes risk.”

The importance of the body's natural circadian rhythm in regulating and anchoring many physiological processes Emphasized The 2017 Nobel Prize in Medicine was awarded to three researchers in circadian rhythm biology, she noted.

“Changes in circadian rhythms are known to affect a variety of factors, including mood regulation, gastrointestinal function, and alertness,” she says. “Maintaining regular sleep habits can help improve circadian rhythms and better regulate many processes, including hormones that control metabolism and appetite.”

Notably, one study Publish online June 27, 2024, Diabetology The study, which included a racially and economically diverse U.S. population, also found that adults with persistently suboptimal sleep (<7 hours or >9 hours per night over an average five-year period) were more likely to develop diabetes. The strongest associations were among participants who reported extreme changes and large fluctuations in their sleep duration.

This research was supported by the National Institutes of Health (grant number R01HL155395) and UKB Project 85501. Kianersi was supported by an American Heart Association Postdoctoral Fellowship. Kianersi and Krieger reported no conflicts of interest.

Marilynn Larkin is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (Contributing Editor), and Reuters Health.