Seasonal changes in HbA1c values from young to elderly diabetic patients

Background: Current research has focused on the seasonal changes in HbA1c at the age of 21-90 years old. Subjects and methods: Subjects were 96 patients with type 2 diabetes mellitus (T2DM). Methods include the classification of group A, B, C by the age with 21-50, 51-70, 71-90 years old. HbA1c values in median were calculated for five consecutive seasons from December 2017 to February 2019. Results: BMI value in 3 group A, B, C was 29.7, 24.7, 25.3, respectively. Basal HbA1c was 7.0%, 7.1%, 7.1%, in 3 groups, respectively. Seasonal changes in HbA1c are as follows: group A showed highest in the summer, group B showed highest in the spring and gradually decreased to the winter, and group C showed gradual decrease and lowest in autumn. Discussion and conclusion: Seasonal changes would be probably from i) working generation with fatigue for persistent hot climate in group A, ii) rather stable daily life with balanced work and rest for the home in group B and C, iii) hot climate from spring to summer may be involved in the changes. Current investigation does not include multiple related factors. Further research will be expected for clarifying various factors.