Higher normal fasting plasma glucose is associated with hippocampal atrophy: The PATH Study

Area of Science:

• Neuroscience
• Endocrinology
• Gerontology

Background:

• Type 2 diabetes (T2D) is linked to cognitive decline and brain atrophy.
• Subclinical effects of plasma glucose within the normal range on brain structures are not well understood.

Purpose of the Study:

• To investigate the association between plasma glucose levels and hippocampal and amygdalar atrophy.
• To examine these effects in cognitively healthy individuals without T2D, aged 60-64.

Main Methods:

• Assessed fasting plasma glucose in 266 participants.
• Measured hippocampal and amygdalar volumes using MRI scans over 2-4 years.
• Employed general linear models to analyze the relationship between glucose and medial temporal lobe atrophy, controlling for covariates.

Main Results:

• Significantly associated plasma glucose levels with hippocampal and amygdalar atrophy.
• Plasma glucose accounted for 6%-10% of volume change in these brain regions.
• Effects were observed even with plasma glucose levels below the diabetes threshold (<6.1 mmol/L).

Conclusions:

• High-normal plasma glucose levels are associated with greater atrophy in the hippocampus and amygdala.
• These findings suggest plasma glucose management may impact cerebral health, even in the subclinical range.
• This research may prompt a reevaluation of normal blood glucose levels and diabetes definitions.