Late chronotype, or a tendency to go to sleep later, has been associated with an increased risk of type 2 diabetes. While previous research suggested this link was due to poorer lifestyle habits of individuals with late chronotype, new data presented at the Annual Meeting of the European Association for the Study of Diabetes indicates that this risk is independent of such factors. Late chronotype is also associated with higher levels of adiposity, which could potentially contribute to the higher risk of type 2 diabetes, although the exact reasons for this association remain unclear. Researchers from Leiden University Medical Center presented their findings at the conference, showing that individuals with a late chronotype had a 55% increased risk of developing type 2 diabetes over a 6-year follow-up period, as well as higher amounts of fat on their waist and liver compared to those with an intermediate chronotype. They also had a higher average BMI and larger waist size.
The researchers analyzed data from almost 5,000 participants without type 2 diabetes from the Netherlands Epidemiology of Obesity study, with 20% of the cohort identified as having a late chronotype. The relationship between chronotype and type 2 diabetes remained significant even after adjusting for various lifestyle factors, suggesting that other mechanisms may be at play. Unexpectedly, the study found that individuals with early chronotypes also had a slightly higher but not statistically significant risk of developing type 2 diabetes compared to those with intermediate chronotypes. Lead researcher Jeroen van der Velde noted a larger waist and more visceral fat in individuals with late chronotype, which may contribute to their increased metabolic risk. The study did not explore the specific reasons behind this increased risk, but the researchers speculate that circadian misalignment or differences in eating patterns may be potential factors.
Our circadian rhythm, or internal clock, plays a crucial role in determining when we sleep, eat, and engage in physical activity. People with late chronotype may experience difficulties adapting to societal schedules that are tailored towards those with early or intermediate chronotypes, such as starting work early in the morning. This misalignment with societal norms can have negative effects on the health of individuals with late chronotype. According to Maria Knobel, MD, a medical director, and expert, society’s emphasis on early chronotypes may leave late chronotypes at a disadvantage, as they may struggle to maintain consistent patterns for sleep, meals, and physical activity. This disruption in routine could potentially contribute to the dysregulation observed in individuals with late chronotypes and increase their risk of metabolic health issues.
Late chronotype and type 2 diabetes risk may be linked through circadian misalignment, as late chronotypes may experience metabolic disturbances due to their internal clocks not being synchronized with societal schedules. Additionally, the timing of food intake, particularly eating later in the evening, may play a role in this association. Time-restricted eating and consuming healthier foods in the evening could potentially help improve metabolic health in individuals with late chronotype. Despite society’s preference for early chronotypes, it is essential to recognize and accommodate the natural variations in individuals’ circadian rhythms to promote optimal health outcomes. Further research is needed to understand the underlying mechanisms connecting late chronotype with an increased risk of type 2 diabetes and adiposity, as well as to develop strategies to mitigate these risks and improve metabolic health in individuals with late chronotype.
