- The risk of type 2 diabetes has been associated with late chronotype, or a tendency to sleep later.
- It was previously assumed that this was due to the poorer habits of people with a late chronotype, but new data presented at the Annual Meeting of the European Association for the Study of Diabetes have suggested that this risk is independent of lifestyle factors. living.
- Late chronotype is associated with higher body fat, which may be associated with a higher risk of type 2 diabetes, but the reasons for this are unclear and may be due to a number of factors, according to the researchers.
“Night owls” are at increased risk of type 2 diabetes, as well as having higher body fat, data presented at a conference showed.
Previous research has shown the link between having a late chronotype, where you feel the need to go to bed later than usual, and type 2 diabetes. This latest research has shown that this link is independent of lifestyle factors, the authors argue.
Previously, peer-reviewed research published in Annals of internal medicinee showed that late chronotype was associated with poorer lifestyle factors, including being more likely to smoke and being less active. This latest, non-peer-reviewed research, presented at the European Association for the Study of Diabetes (EASD) Annual Meeting in Madrid, Spain, held September 9-13, 2024, suggests that the link exists regardless of lifestyle factors .
Researchers from Leiden University Medical Center, Leiden, The Netherlands, presented their abstract to attendees showing the independent association between chronotype and type 2 diabetes.
The researchers analyzed data from 4,999 participants without type 2 diabetes from the Netherlands Obesity Epidemiology study, of whom 54% were women. They determined the participants’ chronotypes based on the information they provided about when they went to sleep and when they got up and calculated using the sleep midpoint. Twenty percent of the group were identified as having a late chronotype.
They showed that the later the mid-sleep point was, the higher a person’s waist measurement, as well as the higher amount of waist and liver fat. The analyzes showed that people they identified as having a late chronotype were not only at a 55% increased risk of type 2 diabetes over a 6-year follow-up, but they also had a higher average BMI, a smaller waist large and higher visceral. and liver fat, than people with an intermediate chronotype.
The researchers adjusted these results for age, gender, education, total body fat, physical activity, diet quality, alcohol intake, smoking, and sleep quality and duration, showing that the link between type 2 diabetes and obesity was independent of these.
Interestingly, the team found different results than expected when they chose to look at the risk for people who had early chronotypes, “From the literature, we expected that early chronotypes would have a similar risk of developing type 2 diabetes as intermediate chronotypes,” says the lead researcher. Jeroen van der VeldePhD, of Leiden University Medical Center. “Our results showed a slightly higher risk, but this was not statistically significant.”
Van der Velde said Medical News Today that he had investigated the link between chronotype and type 2 diabetes because he and others did not believe that lifestyle alone could account for changes in the first risk. The study had shown a more significant effect than expected.
“However, given the observational nature of our study, residual confounding may still have occurred. This means that despite our efforts to control for lifestyle variables such as diet and exercise, these factors may still influence the observed risk change,” he said.
“We didn’t really know what to expect about the associations with waist circumference, visceral fat and liver. In late chronotypes we observed in particular a larger waist and more visceral fat, suggesting that abdominal obesity may play a role in the increased metabolic risk for late chronotypes.
– Jeroen van der Velde
The study did not examine why the later chronotype resulted in this increased risk of type 2 diabetes, but the authors think that the circadian cycle may play a role.
“We believe that, in part, our result can be explained by the circadian misalignment that can occur in people with a late chronotype. From other studies, we know that circadian distortion can lead to metabolic disturbances. The current work or social environment of our society is more suited to people with an early or intermediate chronotype,” Van der Velde said.
“Another explanation could be that people with a late chronotype will also eat late in the evening. Some studies have shown that time-restricted eating, such as not eating after 6 p.m., can help improve metabolic health. Also, the quality of food eaten later in the evening may be less healthy (eg snacks). We adjusted for overall diet quality in our study, but unfortunately, we didn’t measure the timing of food intake,” he explained.
Our circadian rhythm describes the natural oscillation that occurs over a 24-hour period in our body. Our internal clock tells us when to wake up in the morning, when we might feel hungry, when we feel most energetic and when we should sleep.
There is a natural difference between humans that has been observed for generations, hence the concept of ‘night owls’ and ‘early birds’.
Despite this, there are certain periods that society adheres to, for example starting work at a certain time in the morning. This can be difficult for people with a late chronotype to adjust to, since of course, they would still be asleep then.
Maria Knobel, MDand medical director of Medical Cert UK, who was not involved in the research, told Medical News Today:
“Our society is built around the rhythms of early chronotypes, leaving late chronotypes at a disadvantage. Early chronotypes naturally fit into conventional work and school schedules, resulting in more consistent patterns for sleep, meals, and physical activity, all of which are beneficial for metabolic health.”
“On the other hand, late chronotypes are forced to wake up earlier than their bodies would prefer, leading to a cascade of negative health effects. This social discrepancy may be the main cause of what is perceived as dysregulation in late chronotypes,” she said.