Late chronotype, or a tendency to go to sleep later, has been found to be associated with an increased risk of type 2 diabetes. While it was previously assumed that this risk was due to poorer lifestyle habits of people with late chronotype, new data presented at the Annual Meeting of the European Association for the Study of Diabetes suggests that this risk is independent of lifestyle factors. Late chronotype has been linked with higher levels of adiposity, which could potentially increase the risk of type 2 diabetes, although the exact reasons for this are not yet clear. Research presented at the conference showed that individuals with late chronotypes are at a higher risk of developing type 2 diabetes, as well as having higher levels of adiposity, independent of lifestyle factors.
Previous research has also shown a link between having a late chronotype and type 2 diabetes. A study published in the Annals of Internal Medicine found that individuals with late chronotypes were more likely to engage in unhealthy lifestyle behaviors, such as smoking and physical inactivity. However, the new research presented at the EASD conference suggests that the link between late chronotype and type 2 diabetes exists independently of these lifestyle factors. Researchers from Leiden University Medical Center in the Netherlands analyzed data from nearly 5,000 participants without type 2 diabetes and found that those with late chronotypes were at a significantly higher risk of developing type 2 diabetes over a 6-year follow-up period.
The researchers adjusted their results for various lifestyle factors, including age, sex, education, physical activity, diet quality, alcohol intake, smoking, and sleep quality and duration. They found that the relationship between type 2 diabetes and obesity, as indicated by waist circumference and visceral fat, was independent of these factors. Lead researcher Jeroen van der Velde noted that the study yielded unexpected results when examining the risk for individuals with early chronotypes. While early chronotypes were expected to have a similar risk of type 2 diabetes as intermediate chronotypes, the study found a slightly higher risk that was not statistically significant.
Van der Velde suggested that circadian misalignment may play a role in the increased risk of type 2 diabetes among individuals with late chronotypes. Circadian misalignment can lead to metabolic disturbances, which may contribute to the higher risk of type 2 diabetes. Additionally, late chronotypes may be more likely to eat later in the evening, consuming less healthy foods and snacks. Although the study did adjust for overall diet quality, researchers did not measure the timing of food intake. The societal environment, which is structured around early chronotypes, may also contribute to the metabolic health disparities seen in late chronotypes.
Our circadian rhythm dictates our natural sleep-wake cycle and other daily patterns. While there is inherent variation between individuals in terms of their chronotypes, societal norms often favor early chronotypes. This can lead to challenges for individuals with late chronotypes, who may struggle to adapt to early morning schedules that conflict with their natural body rhythms. Dr. Maria Knobel emphasized the detrimental health effects that late chronotypes may experience due to the misalignment between their natural sleep patterns and societal expectations. These findings underscore the importance of considering individual chronotypes and circadian rhythms in understanding and managing the risk of type 2 diabetes and other metabolic disorders.
