Association of glucose levels and glucose variability with mood in type 1 diabetic patients

The aim of this study was to investigate the association of glucose levels and variability of glucose, assessed by continuous glucose monitoring, with mood in type 1 diabetic patients. Thirty-six type 1 diabetic patients (77.8% male, age: 31.1 ± 10.0 years; disease duration: 14.7 ± 7.1 years, BMI: 26.7 ± 5.1 kg/m2, HbA1c 8.4 ±1.8%, 27.8% with continuous subcutaneous insulin infusion [CSII] therapy) used a continuous glucose monitoring system for 48.8 h. During this time the patients rated their current mood states 14.6 times on average, using the University of Wales Institute of Science and Technology Mood Adjective Checklist and hand-held computers. Sensor performance was satisfactory, with a mean absolute difference from reference laboratory glucose measurement of 13.7%. Current glucose values were significantly associated with ratings of ‘tension’ (z = 2.40), ‘hedonic tone’ (z = −2.63) and ‘energetic arousal’ (z = −2.09). ‘Anger’ (z = 1.64) was not significantly associated with glucose values. The glucose AUC during the 60 min prior to the mood rating showed similar associations. The two parameters of glucose variability—coefficient of variation and absolute glucose change during the 60 min prior to the mood ratings—did not show any significant association with the mood ratings. The magnitude of association was significantly higher for glucose level than for glucose variability in the scales ‘tension’ and ‘hedonic tone’. High glucose values had a negative impact on mood; positive mood ratings decreased, whereas negative mood ratings increased. The association between mood and glucose variability seemed to be less important than that between glucose level and mood.