Qualitative and quantitative changes of melatonin levels in physiological and pathological aging and in centenarians.
Level 4 - case-series / case-control
Cross-sectional comparative study evaluating biomarker levels across distinct age and disease groups.
PubMed 15066050 · doi:10.1111/j.1600-079X.2004.00125.x
What was done
Plasma melatonin was measured by radioimmunoassay across eight serial blood samples in healthy young adults (aged 23–39 years), healthy older adults (aged 66–94 years), and patients with senile dementia (aged 68–91 years). In centenarians (aged 100–107 years) and control groups, melatonin was evaluated by measuring urinary 6-hydroxymelatonin sulfate (aMT6s) excretion across two 12-hour collection windows (08:00–20:00 and 20:00–08:00).
What was found
The abstract does not provide exact quantitative values, error margins, or correlation coefficients. It reports that elderly individuals, both with and without dementia, exhibited a flattened plasma melatonin circadian rhythm due to suppressed nocturnal peak secretion. The loss of circadian amplitude was most pronounced in demented patients, and the nocturnal peak significantly correlated with cognitive impairment severity. While urinary aMT6s excretion declined with age, centenarians retained significantly higher nocturnal aMT6s excretion compared to daytime excretion, similar to young controls.
Why it matters
This study links the disruption of circadian melatonin amplitude to pathological aging and dementia, while demonstrating that extreme longevity (centenarians) is characterized by preserved diurnal rhythmicity of melatonin excretion.
Limits
The abstract does not report sample sizes, absolute numerical measurements, or statistical values. Different outcome measures were used across cohorts (serial plasma draws vs. 12-hour urinary aMT6s pools). The cross-sectional design cannot establish causality between melatonin rhythm maintenance and longevity or cognitive decline.
Cited by
- supports Aging leads to a natural decline in endogenous melatonin production.