Circadian rhythm disruption in type 2 diabetes mellitus: A new frontier in metabolic chrono-medicine

Objectives: Type 2 diabetes mellitus (T2DM) is a long-term condition marked by high blood sugar, insulin resistance, and related health problems. Circadian rhythms (our internal 24-h biological clocks) play an important role in regulating body functions, including metabolism. Impairment of these rhythms is thought to contribute to the development of metabolic diseases such as T2DM. The objective of the study is to investigate the correlation between circadian rhythm impairment and T2DM and assess whether this impairment affects the clinical profile of diabetic patients. Materials and Methods: A cross-sectional observational study was conducted at SRN Hospital, MLN Medical College, Prayagraj, from March 2024 to March 2025. A total of 109 postmenopausal women were enrolled and screened for diabetes. Circadian rhythm status was assessed using the composite morningness-eveningness questionnaire (CMEQ). Biochemical markers, anthropometric parameters, and glycemic indicators (fasting blood sugar and glycated hemoglobin [HbA1c]) were evaluated. Results: Among 109 participants, 46 were diabetic. The mean CMEQ score among diabetic participants (45.1 ± 4.25) was comparable to that of nondiabetics (44.4 3.82; p = 0.350), indicating a similar circadian rhythm preference between the two groups. Overall circadian rhythm distribution did not differ significantly according to diabetic status. Importantly, higher morningness-eveningness questionnaire (MEQ) scores reflecting greater morningness were associated with better glycemic status, while participants with lower MEQ scores tended to have higher HbA1c levels. This suggests that a more morning-oriented circadian pattern may be associated with improved glycemic control in postmenopausal women. Conclusion: Although no strong statistical association was found between circadian rhythm type and diabetes, the observed patterns suggest that daily rhythm may play a role in blood sugar control. More long-term and detailed studies are needed to better understand how body clocks affect diabetes and whether adjusting them could help manage the disease.