Lifespan and Causes of Death in the Irish Wolfhound - Vetsuisse ...

previous results (Comfort 1960). No information as to their whelping dates or causes
of death was provided.
The Comfort studies are certainly a very valuable ‘glimpse of the past’. However, it
must also be noted that their focus on one family of dogs from one single kennel is
somewhat problematic if we want to extrapolate Comfort’s findings on the whole
Wolfhound population of the time. Unfortunately, the degree of a possible Cohort
Bias (if any) cannot be deduced from his published data either.
3.1.2.2 Deeb and Wolf
Deeb and Wolf (1994) evaluated data from the Veterinary Medical Database of
Purdue University (www.vmdb.org) of dogs that had died between Jan. 1, 1982 and
Sept. 30, 1992. This included n=116 Irish Wolfhounds. 30 % of these died before age
4, 40 % between ages 4 and 7, 25% between ages 7 and 10, and 5% lived to over 10
years of age (Deeb and Wolf 1994).
The period of death data collection and its grouping by year of death makes it clear
that these results are tainted with Cohort Bias.
3.1.2.3 Li, Deeb et al.
Li, Deeb et al. (1996) published an article on in vitro proliferative capacity of dermal
fibroblasts as a function of body size in dogs and showed that while there were no
gender differences, Wolfhound (and Great Dane) fibroblasts had a significantly lower
proliferative capacity than fibroblasts taken from dogs of other breeds in the same
age class. However, no such correlation was found in other large (but not giant)
breeds.
The paper included a lifespan evaluation of n=236 Wolfhounds provided by the
Veterinary Medical Database of Purdue University (www.vmdb.org), which found that
62% died between 4 to 7 years of age, 32% died between 7 and 10 years, and 6%
died between 10 and 15 years. No reference as to causes of death and/or their
percentual importance was given (Li, Deeb et al. 1996).
The death class of dogs between 10 and 15 years was arbitrarily set by the Purdue
Veterinary Medical Database and might be misleading in the sense that, considering
the rest of the available data as well as the findings of the study at hand, it is highly
improbable that a significant number of Wolfhounds lived past 12 years of age in this
dataset. Furthermore, it is probable that the data used were also right censored,
although the extent to which this was the case remains unknown due to the fact that
no information on death years is given. Similarly, the lack of a death group before
age 4 implies the presence of left censored data, which also reduces the significance
of these findings as far as lifespan is concerned.
3.1.2.4 Michell
Michell (1999) conducted a survey of British dog owners concerning cause of and
age at death of the last dog these owners had had. Nine Irish Wolfhounds were
included in the answers. Mean age was 6.2 years; inter-quartile range was 4.8 years.
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