Causes of death: study revealed the most common causes of mortality in dogs - by breed, age, and size.
The study grouped deaths by organ system and by disease category ("pathophysiological process"), and analyzed results based on age, breed, and average breed size. Eighty-two breeds with at least 100 representatives were included in breed-based analyses; mixed-breed dogs were considered as one group. (For a chart listing causes of death by breed, see page 22.)
Only conditions that led to death were considered; if a dog had multiple conditions, only one was deemed the cause of death.
The study found that cancer was by far the most common disease category cause of death in adult dogs; cancer was the leading cause of death in all but 11 breeds! Almost a third of all adult dogs were found to have died of cancer. Cancer was designated the cause of death almost three times as often as the next most common category of deaths (trauma).
Interestingly, the frequency of cancer deaths begins to taper after age 10.
Cancer occurred less frequently in small breeds, with the exception of the Boston Terrier and Cairn Terrier (30 and 32 percent respectively of deaths in those breeds were from cancer).
The Miniature Pinscher had the lowest rate of cancer at 3.6 percent. Other breeds with low percentages of death from cancer include Miniature Dachshund (6.0), Chihuahua (7.5), Pekingese (7.9), Pomeranian (7.9), Dachshund (8.9), and Maltese (9.2).
The most common causes of death for puppies (dogs less than one year of age) by disease category are very different than for adult dogs. Puppies were overwhelmingly most likely to die of infection, trauma, or congenital disease. About 60 percent of all puppies died from something in these three disease categories.
When looking at deaths classified by organ system, the gastrointestinal and musculoskeletal systems were most commonly involved in the deaths of puppies.
In adult dogs, no single organ system was responsible for a dramatic majority of deaths; seven different organ systems had similar results, ranging from about 8 to 12 percent of adult dog deaths. The leaders (if we can call them that) were the nervous system (neurologic), musculoskeletal, and gastrointestinal systems, followed by the urogenital, hematopoietic, cardiovascular, and respiratory systems.
Older dogs are increasingly likely to die from something involving the cardiovascular system, as well as endocrine, neurologic, and urogenital systems. The frequency of gastrointestinal-related deaths remained fairly constant throughout adulthood, while hematopoietic and musculoskeletal deaths declined with age.
Small-breed dogs were more likely to die from neurologic, endocrine, and urogenital causes. The larger the dog, the more likely they were to die of musculoskeletal and gastrointestinal causes.
Some of the breed differences found were surprising. A higher incidence of cancer in Bernese Mountain Dogs, Golden Retrievers, Scottish Terriers, and Boxers is well-known, but the 47 percent death rate from cancer among Bouvier de Flandres was unexpected.
Cardiovascular disease is well known in toy breeds, such as Chihuahuas and Maltese, because of their high incidence of mitral valve disease, but researchers were surprised to find that the rate was almost as high in Fox Terriers. It's unknown if that's because Fox Terriers are more prone to heart disease than previously realized, or if they're simply more protected from other diseases.
A high proportion of deaths from respiratory disease was expected in Bulldogs due to their brachycephalic airways, but finding that respiratory disease accounted for the highest percentage of deaths in the Afghan Hound and Vizla was unexpected.
EXAMPLES OF ORGAN SYSTEM PROBLEMS
Following are statistics for canine deaths listed by the primary organ system involved, showing the breeds that had the highest rate of deaths attributed to that cause. The number in parentheses indicates the percentage of deaths within each breed for that category. (No organ system was classified for 20 percent of the deaths; these were not included in the rankings). The first five categories were responsible for most deaths in most breeds. ORGAN SYSTEM Breeds with the Highest Rate of Death (and Percentage of those Dogs) Attributed to Each Organ System GASTROINTESTINAL Great Dane (25.6), Gordon Setter (22.5), Akita (212), Shar-Pei (19.9), Weimaraner (17.6) NEUROLOGIC Dachshund (40.4), Miniature Dachshund (39.7), Pug (27.4), Miniature Pinscher (223), Boston Terrier (22.2) MUSCULOSKELETAL Saint Bernard (26.2), Great Pyrenees (25.5), Irish Wolfhound (22.1), Great Dane (21.7), Greyhound (21.4) CARDIOVASCULAR (HEART DISEASE) Newfoundland (23.8), Maltese (21.1), Chihuahua (18.5), Doberman Pinscher (17,2), Fox Terrier (16.3) UROGENITAL Scottish Terrier (17.0), Airedale Terrier (16.3), Dalmatian (16.2), Norwegian Elkhound (16.0), Cardigan Welsh Corgi (15.2), Standard Schnauzer (15.2), Bull Terrier (14.9), Lhasa Apso (14.9), Shetland Sheepdog (14.2), Finnish Spitz (14.0), Shih Tzu (13.9), English Cocker Spaniel (13.7) RESPIRATORY Bulldog (18.2), Borzoi (16.3), Yorkshire Terrier (16.1), Afghan Hound (16.0), Treeing Walker Coonhound (15.1), West Highland White Terrier (14.1), Pomeranian (13.6), Vizsla (13.6) HEMATOPOIETIC Chesapeake Bay Retriever (17.2), Airedale Terrier (15.2), Golden Retriever (15.0), American Cocker Spaniel (14.8), English Cocker Spaniel (13.7), Scottish Terrier (13.2) DERMATO LOGIC (SKIN) Shar-Pei (5.4), West Highland White Terrier (4.9), Miniature Pinscher (4.5), English Pointer (3.6), Chow Chow (2.9), Shetland Sheepdog (2.8) ENDOCRINE Fox Terrier (7.2), Miniature Poodle (6.3), West Highland White Terrier (6.2), Miniature Schnauzer (5.7), Bichon Frise (5.6), Old English Sheepdog (5.6) HEPATIC (LIVER) Scottish Terrier (7.8), English Cocker Spaniel (7.7), Maltese (7.5), Standard Schnauzer (7.2), Pembroke Welsh Corgi (7.0) OPHTHALMOLOGIC (EYE) Akita (9.9), Cardigan Welsh Corgi (3.6), Collie (3.2), Pekingese (3.1), Australian Heeler (3.0)
The study did not provide details about which diseases are included in each category (my mind boggles at the details left out of published studies), but following are some examples of conditions that are likely to be classified in each organ system:
* Gastrointestinal - Gastric dilatation and volvulus (GDV, or bloat) is likely the most common gastrointestinal cause of death; other causes would include pancreatitis, inflammatory bowel disease (IBD), intestinal obstruction, perianal fistula, exocrine pancreatic insufficiency (EPI), lymphangiectasia and other forms of protein-losing enteropathy, and cancer.
* Neurologic - Diseases of the brain and spinal cord, such as intervertebral disc disease (IDD or IVDD) that can cause paralysis; strokes; seizure disorders; degenerative myelopathy; myasthenia gravis; encephalitis; laryngeal paralysis; wobbler syndrome; syringomyelia (common in Cavalier King Charles Spaniels); and tumors of the brain and spinal cord.
This category likely includes cognitive disorders as well, such as canine cognitive disorder (CCD) or cognitive dysfunction syndrome (CDS), similar to Alzheimer's in people. Diseases that cause paralysis, such as tick paralysis, polyradiculoneuritis (coonhound paralysis), and botulism would likely be included in this category.
* Musculoskeletal - Joint problems such as hip dysplasia, elbow dysplasia, and arthritis. Bone cancer would also fall into this category. Trauma is often linked to the musculoskeletal system as well.
* Urogenital - Kidney disease, urinary stones, pyometra (infection of the uterus), and prostate disease. Stones are undoubtedly the major contributor to the Dalmatian's 16 percent of deaths in this category, and probably a big part of the high rates in Lhasa Apsos, Shih Tzu, and Miniature Schnauzers as well.
(For more information about urinary stones, see "Stoned Again?" in the May 2010 issue of WDJ; "Cast in Stone" and "Stone-Free Dalmatians," in the June 2010 issue; and "A Spotty Response," January 2011).
* Respiratory - Brachycephalic airway, collapsed trachea, and pulmonary fibrosis. The Afghan Hound is prone to lung lobe torsion, which may account for their high rate of death in this category. Laryngeal paralysis is not uncommon in Vizslas; perhaps that disease was considered respiratory rather than neurologic by the study.
* Hematopoietic - Relating to blood. Causes might include thrombocytopenia (low platelets), autoimmune hemolytic anemia (AIH A), and disseminated intravascular coagulation (DIC). This category could also include blood-related cancers such as leukemia, lymphoma, and hemangiosarcoma.
* Endocrine - Cushing's disease and diabetes mellitus are the most common endocrine disorders in dogs. Addison's disease would also fall into this category.
EXAMPLES OF DISEASE PROCESSES
Following are statistics for canine deaths listed by disease category, showing the breeds that had the highest rate of deaths attributed to that cause. (Thirty-five percent of deaths were unclassified by a disease category). DISEASE Breeds with the Highest Rate of Death (and Percentage CATEGORY of those Dogs) Attributed to Each Disease Category NEOPLASIA (CANCER) Bernese Mountain Dog (54.6), Golden Retriever (49.9), Scottish Terrier (47.6), Bouvierde Flandres (46.6), Boxer (44.3), Bullmastiff (44.0), Irish Setter (40.8), Airedale Terrier (40.2) TRAUMA Australian Heeler (20.8), American Staffordshire Terrier (20.3), Jack Russell Terrier (19.8), Miniature Pinscher (19.6), Australian Shepherd (17,9), Border Collie (17.5), Chihuahua (16.8), Chow Chow (16.6), Treeing Walker Coonhound (16.4), Greyhound (16.3), Mixed-Breed Dogs (16.2), Beagle (16.0), German Shorthaired Pointer (15.7) INFECTIONS Treeing Walker Coonhound (25.7), American Staffordshire Terrier (21.0), Greyhound (16.5), English Pointer (16.2), Cardigan Welsh Corgi (15.2), English Setter (14.8), Rottweiler (14.8), Black and Tan Coonhound (14.4), Australian Heeler (13.6), Bull Terrier (13.2), Siberian Husky (13.2) CONGENITAL Newfoundland (17.5), Bulldog (13.5), Yorkshire Terrier DISEASE (10.5), Akita (10.4), Maltese (9.7), Pug (8.4) DEGENERATIVE Chihuahua (7.2), Dachshund (6.3), Toy Poodle (5.2), Miniature Poodle (5.1), Pekingese (5.1), Newfoundland (4.5), Maltese (4.1) INFLAMMATORY American Cocker Spaniel (10.5), English Cocker Spaniel (9.4), Keeshond (7.8), Bernese Mountain Dog (7.6), Airedale Terrier (7.3) METABOLIC Doberman Pinscher (11.8), Keeshond (9.7), Cairn Terrier (9.5), Great Dane (8.9), Miniature Schnauzer (8.9), Standard Schnauzer (8.7), Shar-Pei (8.5), Miniature Poodle (8.2), Bichon Frise (8.0), Miniature Pinscher (8.0) TOXIC Australian Heeler (5,3), Australian Shepherd (5.1), American Eskimo (5.0), Miniature Pinscher (4,5), Norwegian Elkhound (3.7) VASCULAR Afghan Hound (2.9), Irish Wolfhound (2.8), Saint Bernard (2.7), Standard Schnauzer (2.5), Mastiff (2.2)
Examples of conditions that were likely to be classified into the different disease process categories:
* Trauma - Injury, such as being hit by a car, or being accidentally dropped or stepped on, especially in the case of toy-breed puppies.
* Infectious - Viral disease, such as parvovirus and distemper; bacterial infections, such as leptospirosis and most tick diseases; fungal infections, such as blastomycosis and histoplasmosis; and protozoal disease, such as babesiosis and leishmaniasis.
* Congenital - A condition present at birth, which may be genetic or caused by something that happened in the womb or during birth. Examples include liver shunts, common in the Yorkshire Terrier and Maltese as well as other toy breeds; and heart defects, common in the Newfoundland and Bulldog, among others.
* Degenerative - Diseases such as degenerative disc disease, hip dysplasia, and other forms of joint disease fall into this category. There are also degenerative diseases of the eyes, heart, and other organs.
* Inflammatory - IBD, pancreatitis, masticatory muscle myositis, and granulomatous meningoencepha-lomyelitis (GME) are inflammatory diseases.
* Metabolic - Anything that affects the organs, including kidney and liver disease. Endocrine diseases would be considered metabolic, along with diabetes insipidus and urinary stones.
* Toxic - Poisoning, such as by ingesting rat poison, toxic mushrooms, or antifreeze.
* Vascular - Stroke (cerebral vascular accident) is the most obvious. Other possibilities include acquired liver shunts and fibrocartilaginous embolism (FCE).
You can use this information to help your dog stay healthy.
First and foremost, keep your dog lean! Overweight dogs are more likely to develop musculoskeletal problems, disc disease, diabetes, heart disease, and even some forms of cancer.
Proper vaccination of puppies protects them from most infectious diseases, though frequent revaccination for viral diseases is unnecessary in adult dogs.
Spayed females cannot get pyometra (uterine infection) and neutered males are less likely to develop prostate disease.
Letting dogs offlead only in protected areas helps prevent deaths due to trauma.
Gastropexy (surgery to tack the stomach to the side of the body wall) to prevent torsion and reduce the risk of fatality from bloat can be performed pro-actively for commonly affected breeds or dogs with close relatives who have bloated, or during bloat surgery.
Even "doggie dementia" can be helped with appropriate supplements and medications (see "Old and Confused," December 2008). EPA, DHA, antioxidants, and mitochondrial cofactors have been shown to improve the performance of older dogs on various cognitive tasks in as little as two to eight weeks.
Recently it's been suggested that the high rate of cancer in Golden Retrievers can be partly traced to a single "popular sire" who sired over 1,000 puppies and later died of hemangiosarcoma. Because this dog and his progeny were used so extensively, the genes predisposing Golden Retrievers to hemangiosarcoma are now so widespread that it is difficult to breed around them. Breeders can help ensure genetic variation and avoid such outcomes by not over-breeding to a single dog or line of dogs.
The hope is that, armed with this new knowledge, veterinarians and owners can be proactive in watching for these diseases, taking preventative measures and beginning treatment early. The information from this study can also help direct breed-specific research on genetic causes and preventative measures for specific diseases.
The table below shows the leading cause of death by organ system, and the top two causes of death by disease category, for The numbers show the percentage within each breed that died from the designated cause. BREED ORGAN SYSTEM % DISEASE % 2ND DISEASE CATEGORY CATEGORY Afghan Hound Resp 16.0 Cancer 35.3 Trauma Airedale Urogen 16.3 Cancer 40.2 Trauma Akita Gastro 21.2 Cancer 20.7 Congen/Trauma Alaskan Malamute Musculo 15.2 Cancer 34,2 Infect/Trauma Am. Cocker Spaniel Hemato 14.8 Cancer 20,0 Inflam American Eskimo Gastro 14.4 Cancer 23.8 Trauma Am. Staffordshire Gastro 15.6 Cancer 22.0 Infect Terrier Australian Heeler Musc/Neuro 12.8 Trauma 20.8 Cancer Australian Musculo 12.8 Cancer 23.6 Trauma Shepherd Basset Hound Neuro 15.2 Cancer 37.8 Trauma Beagle Neuro 13.0 Cancer 23.1 Trauma Bernese Mountain Cardio/Neuro 10.1 Cancer 54.6 Infect Dog Bichon Frise Neuro 13.6 Cancer 21.3 Trauma Black & tan Gastro 15.3 Cancer 22.9 Infect Coonhound Border Collie Musculo 14.3 Cancer 26.1 Trauma Borzoi Musc/Resp 16.3 Cancer 33.7 Infect/Trauma Boston Terrier Neuro 22.2 Cancer 30.4 Metab Bouvier des Gastro 14.2 Cancer 46.6 Trauma Flandres Boxer Neuro 18.2 Cancer 44.3 Trauma Brittany Musculo 12.8 Cancer 26.5 Trauma Bull Terrier Gastro/Uro 14.9 Cancer 21,5 Infect/Trauma Bulldog Resp 18.2 Cancer 20.4 Congen Bullmastiff Gastro 14,9 Cancer 44.0 Trauma Cairn Terrier Neuro 15.3 Cancer 32.2 Infect/Metab Cardigan Welsh Neuro 17.0 Cancer 22.3 Infect Corgi Chesapeake Bay Hemat 17.2 Canter 28.5 Trauma Retr. Chihuahua Cardio 18.5 Trauma 16.8 Infect Chow Chow Gastro 17.4 Cancer 20.6 Trauma Collie Gastro 12,4 Cancer 26.5 Trauma Dachshund Neuro 40.4 Trauma 11.5 Cancer Dachshund, Neuro 39.7 Trauma 12.3 Cancer Miniature Dalmatian Urogen 16.2 Cancer 18.1 Infect Doberman Pinscher Cardio 17.2 Cancer 26.0 Metab English Cocker Gastro 15.4 Cancer 24,8 Inflam Spaniel English Pointer Neuro 12.2 Cancer 33.7 Infect English Setter Neuro 12.2 Cancer 35.7 Infect English Springer Gastro 11.7 Cancer 29.7 Trauma Spaniel Finnish Spitz Neuro 16.8 Cancer 27.1 Infect Fox Terrier Cardio 16.3 Cancer 24.4 Trauma German Shepherd Gastro 15.1 Cancer 27.7 Trauma Dog Germ. Shorth. Musculo 14,7 Cancer 27.0 Trauma Pointer Golden Retriever Hemat 15.0 Cancer 49.9 Trauma BREED % Afghan Hound 9.7 Airedale 7,6 Akita 10.4 Alaskan Malamute 8.9 Am. Cocker Spaniel 10.5 American Eskimo 13.8 Am. Staffordshire 21.0 Terrier Australian Heeler 19.2 Australian 17.9 Shepherd Basset Hound 8,5 Beagle 16.0 Bernese Mountain 8.4 Dog Bichon Frise 8.4 Black & tan 14.4 Coonhound Border Collie 17.5 Borzoi 7.7 Boston Terrier 7.4 Bouvier des 8.0 Flandres Boxer 7.0 Brittany 15.5 Bull Terrier 13.2 Bulldog 13.5 Bullmastiff 9.7 Cairn Terrier 9.5 Cardigan Welsh 15.2 Corgi Chesapeake Bay 12.9 Retr. Chihuahua 10.5 Chow Chow 16.6 Collie 12.7 Dachshund 8.9 Dachshund, 6.0 Miniature Dalmatian 10.4 Doberman Pinscher 11.8 English Cocker 9.4 Spaniel English Pointer 16.2 English Setter 14.8 English Springer 10.2 Spaniel Finnish Spitz 13.1 Fox Terrier 10.4 German Shepherd 11.1 Dog Germ. Shorth. 15.7 Pointer Golden Retriever 7.8 BREED ORGAN SYSTEM % DISEASE | CATEGORY Gordon Setter Gastro 22.5 Cancer Great Dane Gastro 25.6 Cancer Great Pyrenees Musculo 25.5 Cancer Greyhound Musculo 21.4 Cancer Irish Setter Musculo 17.5 Cancer Irish Wolfhound Musculo 22.1 Cancer Jack Russell Terrier Neuro 20.7 Trauma Keeshond Gastro 15.2 Cancer Labrador Retriever Musculo 14.6 Cancer Lhasa Apso Neuro 16.5 Cancer Maltese Cardio 21.1 Congen Mastiff Musculo 17.8 Cancer Miniature Pinscher Neuro 22.3 Trauma Mixed-Breed Dogs Musculo 13.5 Cancer Newfoundland Cardio 23.8 Cancer Norwegian Elkhound Urogen 16.0 Cancer Old English Shepherd Gastro 13.8 Cancer Pekingese Neuro 14,6 Trauma Pembroke Welsh Corgi Neuro 15.7 Cancer Pomeranian Gastro 15.0 Trauma Poodle, Miniature Neuro 13.9 Cancer Poodle, Standard Gastro 16.7 Cancer Poodle, Toy Neuro 16.1 Trauma Pug Neuro 17A Cancer Rhodesian Ridgeback Neuro 17.9 Cancer Rottweiler Musculo 16.3 Cancer Saint Bernard Musculo 26.2 Cancer Samoyed Gastro 13,4 Cancer Schnauzer, Miniature Urogen 13.6 Cancer Schnazuer, Standard Urogen 15.2 Cancer Scottish Terrier Urogen 17.0 Cancer Shar-Pei Gastro 19.9 Cancer Shetland Sheepdog Urogen 14.2 Cancer Shih Tzu Urogen 13.9 Cancer Siberian Husky Gastro 12.5 Cancer Treeing Walker Coonhound Resp 15.1 Infect Vizsla Resp 13.6 Cancer Weimaraner Gastro 17.6 Cancer West Highland White Terrier Resp 14.1 Cancer Yorkshire Terrier Resp 16.1 Cancer BREED % 2ND DISEASE CATEGORY % Gordon Setter 38.3 Trauma 12.5 Great Dane 22.8 Metab 8.9 Great Pyrenees 36,2 Trauma 12.8 Greyhound 21.6 Infect 16.5 Irish Setter 40.8 Trauma 8.0 Irish Wolfhound 31.8 Infect 7.3 Jack Russell Terrier 19,8 Cancer 1/.2 Keeshond 28.0 Metab 9.7 Labrador Retriever 34.0 Trauma 14.1 Lhasa Apso 17.1 Trauma 11,8 Maltese 9,7 Cancer 9.2 Mastiff 30.0 Trauma 12.8 Miniature Pinscher 19.6 Metab 8.0 Mixed-Breed Dogs 27,6 Trauma 16.2 Newfoundland 19,9 Congen 17.5 Norwegian Elkhound 37,4 Infect 10.7 Old English Shepherd 36.0 Infect 8,2 Pekingese 13.0 Infect 8,4 Pembroke Welsh Corgi 30.4 Congen 7.8 Pomeranian 13.1 Infect 8.6 Poodle, Miniature 18.5 Trauma 10.8 Poodle, Standard 27.1 Trauma 10.1 Poodle, Toy 11.7 Cancer 11.4 Pug 12,5 Infect 10.9 Rhodesian Ridgeback 37.4 Infect/Trauma 8.1 Rottweiler 29.6 Infect 14.8 Saint Bernard 26.9 Trauma 10.4 Samoyed 26.1 Trauma 8.6 Schnauzer, Miniature 22.3 Metab 89 Schnazuer, Standard 25.4 Metab 8.7 Scottish Terrier 47.6 Infect 5.9 Shar-Pei 22.9 Infect/Trauma 9.9 Shetland Sheepdog 30.3 Trauma 10.5 Shih Tzu 15.1 Infect 7.5 Siberian Husky 29,5 Infect 13.2 Treeing Walker Coonhound 25.7 Cancer 18.4 Visla 36.4 Trauma 13.6 Weimaraner 25.0 Infect 10.5 West Highland White Terrier 26.3 infect 10,8 Yorkshire Terrier 11.2 Trauma 10.7
Mary Straus does research on canine health and nutrition topics as an avocation. She is the owner of the DogAware.com website.
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|Title Annotation:||HEALTH MATTERS|
|Publication:||Whole Dog Journal|
|Date:||Jun 1, 2011|
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