Cardiac structure and function across the continuum of glucose metabolism

Area of Science:

• Cardiology
• Endocrinology
• Public Health

Background:

• Diabetes and prediabetes are known risk factors for heart failure.
• The impact of glycated hemoglobin (HbA1c) on left ventricular systolic function in the general, non-diabetic population remains unclear.

Purpose of the Study:

• To investigate the association between glycated hemoglobin (HbA1c) levels and global longitudinal strain (GLS) in individuals without diabetes or with prediabetes.
• To assess cardiac function in relation to varying HbA1c levels within a healthy middle-aged cohort.

Main Methods:

• Utilized echocardiography to assess global longitudinal strain (GLS) in 636 healthy middle-aged subjects from the Northern Finland Birth Cohort 1966.
• Categorized participants into low, medium, and high normal HbA1c tertiles, and a prediabetes group for comparative analysis.
• Employed univariate analysis adjusted for covariates to compare cardiac function across different HbA1c groups.

Main Results:

• A significant trend (p < 0.01) of reduced myocardial contractility, indicated by abnormal GLS, was observed with increasing HbA1c levels.
• The prevalence of abnormal GLS was notably higher in the high normal HbA1c group (21.1%) and the prediabetes group (17.9%) compared to the low (7.4%) and medium (12.7%) groups.
• No association was found between HbA1c levels and cardiac structure variables.

Conclusions:

• Elevated HbA1c levels within the high normal range and prediabetes are associated with impaired myocardial contractility in healthy middle-aged individuals.
• These findings suggest that high normal HbA1c and prediabetes may serve as early predictors of heart failure development.
• Further research is warranted to explore the long-term cardiovascular implications of these glycemic states.