Relationship Between Overnight Dexamethasone Suppression Test and Aging.

Area of Science:

• Endocrinology
• Geriatric Medicine
• Hormone Research

Background:

• The hypothalamic-pituitary-adrenal (HPA) axis regulates cortisol production.
• Aging may alter HPA axis activity and cortisol feedback mechanisms.
• The 1-mg dexamethasone suppression test (DST) is used to assess hypercortisolemia.

Purpose of the Study:

• To investigate the relationship between age and suppressed cortisol levels post-1-mg DST.
• To determine if aging impacts the HPA axis's negative feedback regulation.

Main Methods:

• Retrospective analysis of 1-mg DST results from 1111 adults (≥18 years).
• Participants had adrenal incidentaloma or suspected hypercortisolemia.
• Age-dependent correlation analysis was performed across four age groups.

Main Results:

• A strong positive correlation was found between age and post-DST cortisol levels.
• Significant differences in post-DST cortisol levels were observed across age groups (p=0.000).
• Median post-DST cortisol was 18.49 nmol/L overall.

Conclusions:

• The cortisol negative feedback mechanism may be impaired in older individuals.
• The 1-mg DST might produce a higher false-positive rate in the elderly.
• Age is a significant factor influencing DST results in suspected hypercortisolemia.