Seasonal variation in fasting glucose and HbA1c in patients with type 2 diabetes

Seasonal variations in fasting glucose and HbA1c levels in 638 diabetic patients (attending a primary care diabetic clinic during 2003–2007) were examined and found to be significantly higher in colder than in warmer months. Moreover, there were apparent peaks in fasting glucose levels after Christmas and Easter months. This study provides further evidence of monthly fluctuations in glycemic control, underscoring the need to consider seasonal/cultural effects when managing diabetic patients.