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Age and the renin-aldosterone system
Archives of Internal Medicine
|October 1, 1977
Summary
Older adults exhibit lower plasma renin activity (PRA) than younger individuals, impacting low renin hypertension classification. Age significantly influences PRA levels and diagnostic criteria for low renin hypertension.
Area of Science:
- Gerontology
- Cardiovascular Physiology
- Endocrinology
Background:
- Plasma renin activity (PRA) is a key regulator of blood pressure.
- Age is known to influence various physiological parameters, including hormonal regulation.
Purpose of the Study:
- To investigate the effect of age on plasma renin activity (PRA) in normotensive and hypertensive individuals.
- To assess how age influences the classification of low renin hypertension (LRH).
Main Methods:
- Comparison of ambulatory PRA levels between young and older normotensive volunteers under unrestricted and low-sodium diets.
- Analysis of renal function, aldosterone excretion, and plasma renin substrate in both age groups.
- Evaluation of PRA classification using young versus older normotensives as controls.
Main Results:
- Older adults demonstrated significantly lower PRA compared to younger adults, irrespective of diet.
- Renal function, aldosterone excretion, and plasma renin substrate were comparable between age groups.
- Using young controls overestimated the incidence of LRH in older hypertensive patients.
Conclusions:
- Age substantially affects PRA levels and its classification, particularly in the context of hypertension.
- The use of age-specific controls is crucial for accurate diagnosis and understanding of LRH.
- Current diagnostic criteria may misclassify a significant proportion of older individuals due to age-related PRA changes.
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