Association between circadian rhythm and daily glycaemic status

초록

Background and aims: Although it is well-known glycemia can be affected by circadian rhythms, the evidence in a free-living setting was scarce. We investigated the relationship between circadian rhythm and daily glycemic status using continuous glucose monitoring (CGM). Materials and methods: We analyzed data from 77 insulin-treated patients with type 2 diabetes. Participants wore Dexcom G6 and Fitbit for 10 days. Daily percentage of time in the range of 70 to 180 mg/dL (TIR70-180), time <70 mg/dL (TBR<70), and >180mg/dL (TAR>180) were reorganized from CGM data. As a feature of circadian rhythm, we extracted heart rate (HR), sleep, and activity data from Fitbit. Spearman correlation analysis was performed between Fitbit and CGM data with adjustment for age and sex. Results: The mean age and HbA1c levels were 54 ± 12.3 years and 8.1 ± 1.1%, respectively. TIR70-180 was positively associated with amplitude, R2 value, and step counts, whereas there was a negative association between mesor or resting HR with TIR70-180. In general, a more sedentary time during the daytime was related to low TIR70-180, and active minutes during the daytime showed a positive correlation with TIR70-180. TAR>180 exhibited inverse significance with TIR70-180. In the case of TBR<70, there was significance in sedentary time and lightly active minutes. Conclusion: This study showed that an intact circadian rhythm estimated by a wearable activity tracker was related to CGM-derived glycemic status.