The GRCA Electronic Health Survey at 1 Year: Data on Longevity and Cancer
GRCA Health and Genetics Committee
On February 14, 2012 the GRCA Electronic Health Survey reached 1 year of age. This survey was intended to be something that we can all participate in to help the breed we love. While not a scientific survey, this survey helps to track major health problems and provides a very interesting snapshot of potentially emerging trends. However, there are many ways that bias can skew data from this kind of survey, such as a tendency for owners whose dogs have significant problems to complete the survey in greater numbers than owners of healthy dogs. At the opposite end of the scale, there was no control against entering very young dogs into the survey, perhaps prior to the development of health conditions that will only be evident as they age. Thus we must be careful not to weigh any results from this survey too heavily and at this point in time the scientifically validated 1998- 1999 Golden Retriever Health Survey remains the gold standard. Still, the Electronic Health survey is valuable in its own way and remains open, and owners are encouraged to continue entering dogs.
Survey data were available for 1914 living Golden Retrievers and 1511 Goldens who had died. Slightly more females (1849) than males (1574) were recorded in the survey. Geographically, nearly all US states were represented, and just under 100 Canadian dogs were entered. This is a summary of the findings on longevity and cancer. We hope to summarize the findings on heritable diseases such as hip dysplasia, elbow dysplasia, subaortic stenosis, inherited eye disease, and other miscellaneous health conditions for the next issue of GR News.
The good news is that in the ongoing survey there were more Golden Retrievers living 10 or more years (1026) than those living less than 10 years (503). For comparison purposes, the mean age at death for all dogs in a British survey of all breeds was reported to be 11 years and a month, with age at death from natural causes being roughly a year and a half longer (Michell et al, 1999). However, large dogs tend to live shorter lives than small dogs (Egenvall et al, 2005; Jones et al, 2008; Chase et al, 2009) — and clearly Golden Retrievers are not small dogs! Our 1998-1999 Health Survey indicated that the average Golden female lived 11.3 years and the average Golden male lived 10.7 years (Glickman et al, 1999). Thus, there is no evidence for a major shift in lifespan of Golden Retrievers since the 1999 survey. Table 1
The bad news is not new – we have too many Golden Retrievers dying of cancer. The four most common types of cancer in the new survey were hemangiosarcoma (370), lymphoma (170, mast cell tumors (92) and osteosarcoma (54). These were also the top 4 cancers in the 1998 – 1999 Health Survey (Glickman et al, 1999). Table 2 and Table 3
In the 1998 – 1999 Health Survey, use of drop-on flea and tick prevention products, or flea/tick shampoos and sprays significantly decreased the frequency of lymphoma, while a significant decrease in hemangiosarcoma was associated with the use of drop-on flea and tick prevention products. Similarly, a 2008 North Carolina-based scientific study showed that healthy Golden Retrievers were more likely to receive regular flea/tick prevention than those with lymphoma (Duncan et al, 2008). The data in the current survey did not show the same decreased risk with the use of flea prevention drop-on treatments; however, this was not a scientific study and associations may have been missed because there was no ability to correlate specific dogs with specific results. Table 4
The current survey did show a significant number of cases of vector-borne disease (154, or nearly 5% of responses), although this is lower than the 18% of Goldens with vector-borne disease (Bartonella spp) reported in the 2008 Duncan et al study. Is it possible that vector-borne diseases play a role in Golden Retriever hemangiosarcoma and lymphoma? The answer is that we do not know. Vector-borne diseases can stimulate an immune response, and lymphocytes involved in immune response are the cell type of origin for lymphoma. So that question may be worthy of study but is not something we should worry about today. However, knowing the right questions to investigate can lead to important breakthroughs and it is always a good idea to keep Goldens free from fleas and ticks. In the meantime, we can take comfort in knowing that the modern drop-on flea and tick prevention products do not appear to be associated with increased Golden Retriever cancers.
So what about those questions about water sources and toys? The basis for those questions was that most garden hoses are NOT approved for use as a source of drinking water. Many garden hoses are made of polyvinyl chloride and lead is used as a stabilizer which can leach into the water (Mays, 2010) and workers in the polyvinyl chloride industry are at increased risk for angiosarcoma (the human equivalent of hemangiosarcoma) and lymphoma (Gennaro et al, 2008). Certainly dogs should not be drinking from hoses if they leach lead, but were Golden Retrievers drinking from garden hoses and could that be associated with cancer? The survey indicates that only a small percentage of Golden Retrievers (2 % of those with hemangiosarcoma and 3% of those without hemangiosarcoma) have water from the hose as their major source of water. Hopefully those Golden Retrievers are getting their water from the relatively small percentage of hoses intended to produce drinking water. With regard to toys, Golden Retrievers spend a great deal of their time with toys in their mouths and thus may have high exposure to substances found in those toys, but no clear trends appeared to suggest different exposures among Goldens with hemangiosarcoma as compared to healthy dogs. Table 5
There are no significant differences between dogs affected with hemangiosarcoma and healthy dogs with regard to their exposure to various water sources and with regard to their likely exposure to favorite toys.
So our quick snapshot indicates that we still have a problem with cancer and that is not a surprise. As many GRCA members know, improvements in canine cancer prevention and treatment have had a relatively slow start but have benefited from the war on human cancer which began in 1971. The successes in human cancer have combined with many recent publications in canine cancer to form the basis for a much brighter future for those who own Goldens today. The first drug specifically designed to combat canine cancer, toceranib phosphate (Palladia®, Pfizer Animal Health), was approved by FDA in 2009. Palladia® is a tyrosine kinase inhibitor currently used as part of the treatment regimen for some aggressive mast cell tumors and under investigation for use in treatment of other kinds of canine cancer. Undoubtedly, this is the first of many such advances in our ability to prevent and treat cancer in dogs. In terms of genetic causes, the Broad Institute website now indicates that they have identified several genetic regions associated with increased risk for hemangiosarcoma. Importantly, the Health and Genetics Committee has heard from several researchers that the 1998 – 1999 scientific Golden Retriever health survey helped them in planning their studies. Likewise, the current ongoing survey is helpful in establishing priorities for future research studies.
A major scientific study may soon help to identify nutritional and environmental factors — and genetic factors — which influence Golden Retriever cancers. The new study, which is part of Morris Animal Foundation’s Canine Lifetime Health Project, will provide scientific data that is much more accurate than a survey. The study will enroll Golden Retrievers before they have disease and follow them for 10 to 14 years. The announcement of this study is available online at
http://www.morrisanimalfoundation.org/blog/category/dog/historys-largest-dog-study.html and enrollment information is available at https://www.caninelifetimehealth.org/#About/GoldenRetrieverLifetimeStudy
Chase K, P Jone A Martin, EA Ostrander, KG Lark. 2009. Genetic Mapping of fixed phenotypes: Disease Frequency as a Disease Characteristic. J. Hered. 100 (S1): S37-S41.
Duncan AW, HS Marr, AJ Birkenheuer, RG Maggi, LE Williams, MT Correa, EB Breitschwedt. 2008. Bartonella DNA in the blood and lymph nodes of Golden Retrievers with lymphoma and in healthy controls. J. Vet Intern Med 22(1):89-95
Egenvall A, BN Bonnet, A. Hedhammer, P Olson. 2005. Mortality in over 350,000 insured Swedish dogs from 1995-2000. II. Breed-specific age and survival patterns and relative risk for causes of death. Acta Vet Scand 46(3):121-136.
Gennaro V, m Ceppi M, P Crosignani, and F Montanaro. 2008. Reanalysis of updatedmortality among vinyl and polyvinyl chloride works: Confirmation of historical evidence and new findings. BMC Public Health. 8: 21.
Glickman L., N. Glickman and R. Thorpe. 1999. The Golden Retriever Club of America National Health Survey, 1998-1999. Available online at https://www.grca.org/health/reports.html
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Michell AR. 1999. Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease. Vet Rec 145(22):625-9.