From:
AFERRETVET@cs.com
Date: 2001-04-01 15:41:00 UTC
Subject: Re: [Ferret-Health-list] ReThe Dutch Article
Hi Sukie,
The article I refereed to was called, "Correlation between age
at neutering and age at onset of hyperadrenocorticism in ferrets."
It was published in the Jan. 15, 2000 issue of Journal of the
American
Veterinary Medical Association. 3 of the 4 authors were from the vet
school
(Utrecht University, Utrecht, The Netherlands) and 1 was from a
private
practice.
I'll type the last paragraph of the article which sums up the
article.
" In our study, mean age of ferrets with hyperadrenocorticism was
5.1
+- 1.9 years-significantly older than affected ferrets (mean age,
3.4 +-1.4
years; n=50) reported by Rosenthal et al. In The Netherlands,
ferrets are neutered at 0.98+-0.65 years of age: American ferrets
are
commonly neutered at 4 to 6 weeks of age. The interval between age
at
neutering and age
at diagnosis in the Dutch ferret population (3.5+-1.8 years) was,
however,
similar to that in the population studied by Rosenthal et al (3.3
+-1.4
years), assuming that those ferrets were neutered at 6 weeks of age.
Although a significant correlation between age at neutering and age
at development of hyperadrenocorticism is apparent, an explanation
for this relationship has yet to be found. It has been speculated
that,
after neutering, the adrenal cortices are persistently stimulated by
luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as a
result of the loss of negative gonadal feedback on hypothalamic
gonadotropin releasing hormone(GnRH), and this results in
adrenocortical hyperplasia or tumorigenesis; Donovan and Ter Haar
detected increased plasma concentrations of LH and FSH in spayed
female ferrets. Luteinizing hormone receptors have been found
in the adrenal glands of humans, suggesting that increasing LH
concentrations
in plasma could be a triggering factor of development of adrenal
tumors.
The successful use of the GnRH agonist leuprolide (Lupron) for
medical control of hyperadrenocorticism strengthens the hypothesis
that neutering plays a role in the development of
hyperadrenocorticism
in ferrets."
I am not a math expert, so I cannot comment on your "fuzzy math"
comment. However the analysis used, "the Pearson coefficient of
linear
correlation was calculated to determine the relationship between
age at neutering and age at diagnosis. Differences between groups
were tested by use of X2 analysis or Student t-test. Prevalence of
hyperadrenocorticism (percentage, confidence interval[CI]) in the
survey population was calculated. Differences were considered
significant at P<0.05" is a common method.
Jerry Murray, DVM