Association of chronotype with glycemic control, sleep patterns and meal timings among adults with type 2 diabetes mellitus

Background: Type 2 Diabetes Mellitus (T2DM) is a major public health concern, with lifestyle factors such as chronotype potentially influencing glycemic control and daily behavioral patterns. The present study aimed to assess the association of chronotype with glycemic control, sleep patterns, and meal timings among adults with type 2 diabetes mellitus. Methods: A hospital-based cross-sectional study was conducted among 100 adults with T2DM attending Yashoda Hospital, Malakpet, Hyderabad. Data were collected using a structured questionnaire, clinical records, and the Reduced Morningness-Eveningness Questionnaire (rMEQ). Glycemic control was assessed using fasting blood glucose (FBG), postprandial blood glucose (PPBG), and glycated haemoglobin (HbA1c). One-way analysis of variance (ANOVA) and Chi-square tests were used for statistical analysis, with p<0.05 considered statistically significant. Results: The intermediate chronotype was the most prevalent (49%), followed by the evening chronotype (28%) and morning chronotype (23%). The mean HbA1c was highest among participants with the evening chronotype (8.257±1.641%) and lowest among those with the morning chronotype (7.617±0.780%); however, the difference was not statistically significant (p=0.242). Similarly, no significant associations were observed between chronotype and FBG (p=0.962) or PPBG (p=0.725). Significant associations were observed between chronotype and wake-up time (p<0.001), bedtime (p<0.001), lunch timing (p=0.013), and dinner timing (p=0.004). No significant associations were observed with breakfast timing (p=0.089), sleep duration (p=0.640), sleep quality (p=0.109), or BMI (p=0.229). Conclusions: Chronotype was significantly associated with certain daily behavioral patterns, particularly wake-up time, bedtime, lunch timing, and dinner timing, but was not significantly associated with glycemic control in the study population.