Pupillary light reflex in borderline diabetes mellitus

Area of Science:

• Endocrinology
• Diabetology
• Neurology

Background:

• Diabetes mellitus is characterized by impaired early-phase insulin release.
• Autonomic neuropathy frequently develops in individuals with diabetes.
• Autonomic nerve function influences insulin secretion in healthy individuals.

Purpose of the Study:

• To investigate autonomic function in relation to early-phase insulin release in borderline diabetes mellitus (B-DM) and early diabetes mellitus (E-DM).
• To identify sensitive markers for detecting autonomic neuropathy in early stages of diabetes.

Main Methods:

• Assessment of autonomic function using pupillary light reflex and cardiac beat-to-beat variation.
• Evaluation of early-phase insulin release response to glucose loading.
• Comparison of autonomic function across different degrees of insulin release impairment in B-DM and E-DM.

Main Results:

• Autonomic neuropathy was detected in B-DM, albeit less severe than in E-DM.
• Parasympathetic nerve impairment was more pronounced than sympathetic impairment in B-DM, especially with better insulin release.
• Autonomic neuropathy, particularly sympathetic abnormalities, worsened with reduced insulin release in B-DM and was more advanced in E-DM.

Conclusions:

• Autonomic neuropathy is present even in the early stages of diabetes and borderline diabetes mellitus.
• Parasympathetic dysfunction may contribute to the suppressed early-phase insulin release in B-DM.
• Autonomic nerve dysfunction is a critical factor in understanding the pathogenesis of borderline and early diabetes mellitus.