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[Evaluation of seasonal changes in hemoglobin A1c in diabetic patients]

Machi Furuta1, Ryuya Tomisaka, Akiko Yamana

  • 1Clinical Laboratory Medicine, Wakayama Medical University, Wakayama 641-8509, Japan. machi@wakayama-med.ac.jp

Rinsho Byori. the Japanese Journal of Clinical Pathology
|September 15, 2012
PubMed

Insights

Seasonal variations impact hemoglobin A1c (HbA1c) levels, peaking in spring and lowest in autumn. These glycemic changes in diabetic patients warrant consideration in clinical research and treatment evaluations.

Area of Science:

  • Endocrinology
  • Metabolic Health
  • Clinical Research

Background:

  • Hemoglobin A1c (HbA1c) is a key indicator of long-term glycemic control.
  • Understanding factors influencing HbA1c variability is crucial for effective diabetes management.
  • Previous research has not fully elucidated the extent of seasonal influences on HbA1c levels.

Purpose of the Study:

  • To investigate seasonal fluctuations in HbA1c values.
  • To identify specific periods of the year with highest and lowest HbA1c.
  • To assess the impact of seasonal changes on diabetic patients, particularly those on insulin therapy.

Main Methods:

  • Analysis of HbA1c data from 34,590 patients in 2010, with monthly averages calculated.
  • Longitudinal analysis of HbA1c trends from 2006 to 2009.
  • Evaluation of seasonal HbA1c averages in 453 diabetic patients with stable treatment regimens.

Main Results:

  • A distinct seasonal pattern in HbA1c was observed, with levels highest in March and lowest in October (0.30% difference).
  • Similar annual patterns were consistent from 2006 to 2009.
  • Diabetic patients exhibited significant seasonal variations, with peak HbA1c in spring and lowest in autumn, most pronounced in insulin-treated individuals.

Conclusions:

  • Significant seasonal variations in HbA1c levels exist in the general patient population and diabetic individuals.
  • Factors such as climate, physical activity, diet, and weight changes likely contribute to these seasonal glycemic fluctuations.
  • Awareness of seasonal HbA1c changes is important for health service research, clinical trials, and treatment efficacy assessments.

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