Rapidly exchangeable pool study of zinc in free-living or institutionalized elderly women.
OBJECTIVE
We evaluated the effect of age and institutionalization on zinc metabolism by using a stable isotope technique.


METHODS
This was a randomized case-control study. Three groups were recruited: nine young women (group 1, ages 36+/-1 y) as controls, nine free-living elderly women (group 2, ages 72+/-2 y), and nine institutionalized women (group 3, ages 73+/-2 y). Only women were recruited to obtain homogeneous groups. The study was set in a Valence hospital (France) in the geriatric department (headed by Dr. Ferry). The experimental design of the study was reviewed and approved by the local ethical committee, and all participants signed a consent form. No subject dropped out of the study. A zinc stable isotope label (0.73 mg of (70)Zn) was injected intravenously into patients and measured by inductively coupled plasma mass spectrometry.


RESULTS
Decay curves of the plasma (70)Zn followed a one-compartment kinetic leading to the determination of one pool. The size of this pool suggested that it corresponded to the liver compartment. The size of this pool was significantly smaller in elderly people. (70)Zn plasma resident time was significantly longer in elderly individuals, and shorter in institutionalized than in free-living elderly subjects.


CONCLUSIONS
These data suggest that the zinc metabolism of elderly women is related to lifestyle or its consequences and to age. Moreover, we have demonstrated that kinetic studies using stable isotopes of zinc can provide novel information on exchangeable zinc pools in clinical situations.
Laboratoire HP2, Faculté de Médecine et de Pharmacie, BP 217, Grenoble, France. pfaure@chu-grenoble.fr
Patrice
P
Faure
Véronique
V
Ducros
François
F
Couzy
Alain
A
Favier
Monique
M
Ferry
D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000378:metabolism*; D019540:Area Under Curve; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007326:Institutionalization; D007553:Isotope Labeling; D008019:Life Style; D008099:Liver / Q000378:metabolism; D015032:Zinc / Q000378:metabolism / Q000493:pharmacokinetics*; D015033:Zinc Isotopes
D015033:Zinc Isotopes; D015032:Zinc