Exploring the Link between Evening Chronotypes and T2DM among South Indians: A Cross-Sectional Study

Chronotype refers to an individual's circadian preference in biological and behavioral rhythm relative to the external light-dark cycle. light-dark cycle. Evening chronotype is associated with increased diabetes risk, probably due to inappropriate eating habits, reduced physical activity, and altered sleeping habits. This study aims to find an association between evening chronotropic and diabetes.

A cross-sectional study was conducted in the General Medicine department over six months. 201 patients satisfying the study criteria were included. Horne-Ostberg Morningness- Eveningness Questionnaire (MEQ), blood samples, sleep quality, and anthropometric indicators were obtained. Postprandial blood sugar (PPBS), fasting blood sugar (FBS), glycated hemoglobin (HbA1c), Total cholesterol (TC), triglycerides (TGs), High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and very low-density lipoproteins (VLDL) were measured with standard techniques. A univariate logistic regression analysis, along with post-hoc tests, was employed to find the role of independent variables on each chronotype.

Among the 81 evening chronotypes, 85.1% were diabetics, the mean HDL value in the evening chronotypes was 35.2 mg/dl, significantly (p<0.001) lower than the other two chronotypes. Waist-to-hip ratio (WHR) and body mass index (BMI) were significantly higher in the evening chronotype p= 0.011, p<0.001, respectively. The mean FBS, PPBS, and HbA1c values (170.07 mg/dL, 242 mg/dL, and 8.95%) were higher among evening chronotypes and were statistically significant (p<0.001).

Findings highlight that evening chronotypes demonstrate poorer glycaemic control, dyslipidaemias, and adverse anthropometric indices, suggesting that circadian misalignment may contribute to T2DM progression. Lifestyle modification could be a promising intervention.

Our study suggests Evening chronotypes are more likely to have metabolic dysregulation and poor glycemic control.