A study presented at the European Association for the Study of Diabetes 2024 Annual Meeting examined the associations between chronotype, body composition, and type 2 diabetes risk.

Researchers from Dutch institutions analyzed data from the Netherlands Epidemiology of Obesity study involving 5,026 participants (54% women) with a mean age of 56 years and a mean body mass index (BMI) of 30 kg/m². Chronotypes were categorized based on midpoint of sleep (MPS): late (MPS ≥ 4:00), intermediate (MPS 02:30–04:00), and early (MPS < 2:30). The intermediate chronotype served as the reference category.

Participants with late chronotype had a higher risk of developing T2D compared with those with intermediate chronotype (hazard ratio [HR] = 1.46). Late chronotype was associated with a 0.7 kg/m² higher BMI, 1.9 cm larger waist circumference,1.9 cm larger waist circumference, 7 cm² more visceral fat, and 14% more liver fat.

Of participants, 20% were classified as having a late chronotype. During a median follow-up of 6.6 years, 225 participants were diagnosed with T2D.

The researchers employed various techniques to assess body composition, including BMI and waist circumference were measured in all participants Visceral fat was quantified using MRI in a subset of 1,576 participants. Liver fat was measured using MR spectroscopy in the same subset.

Statistical analyses included linear regression for cross-sectional associations between late chronotype and body fat measures and Cox regression for calculating HRs of T2D.

All analyses were adjusted for age, sex, education, physical activity, diet, and sleep quality and duration

Exclusion criteria for the analysis included lost to follow-up, preexisting T2D, or missing MPS or covariate date.

The researchers collected T2D incidence data through electronic health records. They defined chronotype using the midpoint of sleep, calculated from self-reported sleep timing information.

The authors declared having no competing interests.