Individuals with a late chronotype, or those who are biologically inclined to stay up late, face a heightened risk of developing type 2 diabetes (T2D), according to a study presented at the European Association for the Study of Diabetes' annual meeting held in Madrid from September 9 to 13.

The research, led by Dr. Jeroen H.P. van der Velde from Leiden University Medical Center in the Netherlands, explored the link between chronotype and various health indicators, including body mass index (BMI), waist circumference, visceral fat, liver fat, and the likelihood of developing T2D. The study utilized data from the Netherlands Epidemiology of Obesity study, analyzing 5,026 participants over a median follow-up period of 6.6 years.

The participants were divided into three chronotypes based on their mid-point of sleep (MPS): early, intermediate, and late. Those with a late chronotype (MPS ≥4:00 a.m.) constituted 20% of the study's sample. The findings revealed that people with a late chronotype had a 46% increased risk of developing T2D compared to those with an intermediate chronotype (MPS between 2:30 a.m. and 4:00 a.m.).

Additionally, participants with a late chronotype exhibited less favorable health indicators. They had a 0.7 g/m² higher BMI, a 1.9 cm larger waist circumference, 7 cm² more visceral fat, and 14% more liver fat compared to their intermediate counterparts. These factors, particularly the accumulation of visceral and liver fat, are known contributors to the onset of type 2 diabetes.

“People with a late chronotype appear to be at greater risk of developing type 2 diabetes compared to those with intermediate chronotype, possibly because of higher body fat including more visceral fat and liver fat,” van der Velde explained.

The study highlights the potential health risks linked to sleep patterns and reinforces the importance of understanding chronotypes in managing diabetes risk. As more individuals adopt irregular sleep schedules due to modern lifestyles, these findings serve as a call for further research and potential public health interventions.