Tag Archives: research

Dogs reduce your risk of heart disease

The American Heart Association has released a scientific statement citing the link between pet ownership and reduced risk of heart disease.

The statement is published online in the association’s journal Circulation.

“Pet ownership, particularly dog ownership, is probably associated with a decreased risk of heart disease” said Glenn N. Levine, M.D., professor at Baylor College of Medicine in Houston, Texas, and chair of the committee that wrote the statement after reviewing previous studies of the influence of pets.

Research cited to support that statement includes:

  • Pet ownership is probably associated with a reduction in heart disease risk factors and increased survival among patients.  “It may be simply that healthier people are the ones that have pets, not that having a pet actually leads to or causes reduction in cardiovascular risk,” Levine said. (Disclaimer:  These studies aren’t definitive and do not necessarily prove that owning a pet directly causes a reduction in heart disease risk.)
  • Dog ownership in particular may help reduce cardiovascular risk. People with dogs may engage in more physical activity because they walk them. In a study of more than 5,200 adults, dog owners engaged in more walking and physical activity than non-dog owners, and were 54 percent more likely to get the recommended level of physical activity.
  • Owning pets may be associated with lower blood pressure and cholesterol levels, and a lower incidence of obesity.
  • Pets can have a positive effect on the body’s reactions to stress.

“In essence, data suggest that there probably is an association between pet ownership and decreased cardiovascular risk,” Levine said. “What’s less clear is whether the act of adopting or acquiring a pet could lead to a reduction in cardiovascular risk in those with pre-existing disease. Further research, including better quality studies, is needed to more definitively answer this question.”

Even with a likely link, people shouldn’t adopt, rescue or buy a pet solely to reduce cardiovascular risk, Levine said.

Statement co-writers are: Karen Allen, Ph.D.; Lynne T. Braun, Ph.D., C.N.P.; Hayley E. Christian, Ph.D.; Erika Friedmann, Ph.D.; Kathryn A. Taubert, Ph.D.; Sue Ann Thomas, R.N., Ph.D.; Deborah L. Wells, Ph.D.; and Richard A. Lange, M.D., M.B.A.

Source:  American Heart Association media statement

What we share with our dogs

We all know that we share love with our dogs.  But microbes?

A new CU study indicates parents are more likely to share bacteria with their dogs than their kids,  a finding with biomedical implications. Photo courtesy Natural Resources Conservation Services

A new study indicates parents are more likely to share bacteria with their dogs than their kids. Photo courtesy Natural Resources Conservation Services

Researchers at the University of Colorado Boulder have looked at the types and transfer modes of microbes from the guts, tongues, foreheads and palms (or paws) of members of 60 American families, including dogs.  They found that humans shared more microbes with their dog than their own children.

The team swabbed various parts of the body to obtain microbial samples on  couples, children and dogs.  For humans, the team looked at the tongue, forehead, right and left palm and fecal samples to detect individual microbial communities. Dogs were sampled similarly, except that fur was sampled instead of skin on the forehead and all four paws were swabbed for bacteria in the absence of canine palms.

“One of the biggest surprises was that we could detect such a strong connection between their owners and pets,” said Associate Professor Rob Knight, the study’s leader.

The micro-organisms humans carry around have been linked to a broad spectrum of diseases ranging from malnutrition and obesity to diabetes, asthma and depression.  “There is mounting evidence that exposure to a variety of environmental sources of microbes can affect long-term health, findings known as the ‘hygiene hypothesis,’ ” said doctoral student Se Jin Song.

Proposed by British epidemiologist Richard Strachen in 1989, the hypothesis is that children who have had a lack of exposure to bacteria and micro-organisms might be more prone to getting sick because many microbes have co-evolved with people to be beneficial.

Dogs were a key part of this research, said Knight.  “Since so many people consider their pets truly a part of the family, it seemed appropriate to include them in a study involving family structure.”

The results of the study have been published in the journal eLIFE.

Source:  University of Colorado at Boulder media statement

Do sterilized dogs live longer?

New research from the University of Georgia suggests that neutering procedures could add to the length of a dog’s life and alter the risk of specific causes of death.

Looking at a sample of 40,139 death records from the Veterinary Medical Database from 1984-2004, researchers determined the average age at death for intact dogs—dogs that had not been spayed or neutered—was 7.9 years versus 9.4 years for sterilized dogs.

These figures may seem low considering how many pets live much longer, but the researchers noted that the life spans would be lower than those seen more widely because their sample was taken from dogs seen at teaching hospitals (so other things would have been going on and the study population would have had more sick animals).

The researchers stand behind their results – that the difference between neutered and intact is real.

Dr. Kate Creevy, an assistant professor of internal medicine at the College of Veterinary Medicine. “The question that raises is why would you die younger if you have offspring?”

For the first time, researchers have been able to measure costs of reproduction in terms of the actual causes of death, finding that the causes of death differed between sterilized and intact dogs. Dogs who had undergone a gonadectomy (a spay or castration) were more likely to die from cancer or autoimmune diseases. Those in the sample who still had functional reproduction systems at death were more likely to die from infectious disease and trauma.

“Intact dogs are still dying from cancer; it is just a more common cause of death for those that are sterilized,” said Jessica Hoffman, a UGA doctoral candidate in the Franklin College of Arts of Sciences who co-authored the study.

Some of the reproductive hormones, particularly progesterone and testosterone, she said, could suppress the immune system, explaining why there is an increased risk of infection among dogs that have been sterilized.

The full journal article, published in PLoS One, can be viewed here.

Source:  University of Georgia media statement

Pet obesity at the molecular level

A University of Illinois research team led by Professor Kelly Swanson has published research which describes how nutrients and biological compounds in foods can affect gene expression in animals.

The research will help to understand the underlying reasons for obesity in pets.  Professor Swanson explains that obesity has its roots in the domestication of dogs.  Because dogs no longer hunt or compete for their food and are speyed or neutered (so not having to mate),  the typical dog has much smaller energy requirements than its forefathers.

The research team explains that when more energy (food) is consumed than is required, it is stored as fat in the adipose tissue (fat tissue).  Adipose tissue secretes more than 50 substances known as adipokines, which are cell-signaling molecules that are involved in metabolism, immunity and inflammation.

In obese dogs, levels of the adipokine leptin increases while the levels of the  adipokine adiponectin decreases.

The researchers aim to study obesity at the molecular level, so they can help to prevent it happening.

Source:  University of Illinois media statement

Dogs are a ‘social lubricant’ in helping people with autism

Research published in the open access journal PLoS ONE indicates that the presence of an animal can significantly increase positive social behaviors in children with autism spectrum disorders (ASD).

Autistic boy with dog

Previous studies have shown that people are more likely to receive overtures of friendship from strangers when walking a dog than when walking alone. The authors suggest that this ‘social lubricant’ effect of animals on human social interactions can be particularly important for individuals with socio-emotional disabilities.

In this study, the authors compared how 5-13 year old children with ASD interacted with adults and typically-developing peers in the presence of two guinea pigs compared to toys.  When the guinea pigs were present, the children were more likely to talk and look other people in the eye plus they smiled and laughed more often.

These results indicate that animal-assisted therapy programmes may be useful in helping children with ASD integrate into classrooms and other social environments.

Source:  Science Daily

Dogs and history: blood transfusions

A little bit of history in this post.  Did you know that the dog had a key role in the development of blood transfusion technology in humans?

Unfortunately, this is a story of animal experimentation.

blood tranfusion bag

In the early 1600s, an English physician named William Harvey explored the circulatory system and declared that ‘blood must continuously circulate.’  For the next 50 years, more work was done to understand the circulatory system.  Dogs were unfortunately chosen for animal experimentation and they were injected intravenously with a range of fluids including opium, wine and ale.

In 1665, English physician Richard Lower drained the blood out of a dog almost to the point where it had no blood volume left and was on the verge of death.  He then took a larger dog and replaced the blood supply.  (Poor dogs)

If you are really interested in the topic of human blood donation, this Science Show video on YouTube explains the whole history of human blood donation…

Getting your head around dog genetics

Another public release of research this week.  This one from the Genetics Society of America about an article entitled ‘The Genetics of Canine Skull Shape Variation.’  Published in the February issue of Genetics, researchers review progress in defining genes and pathways that determine dog skull shape and development.

The researchers believe that the results are useful to humans because of the genetic expression of the features is likely to be similar process in humans as in dogs.

Skull shape is a complex trait, involving multiple genes and their interactions. Thanks to standardized canine breeding, which documents more than 400 breeds worldwide, and their distinct morphological features, researchers can disentangle traits such as skull shape, which in many breeds is a breed-defining variation.

Researchers are beginning to identify which genes cause a Bulldog or a Pug to have short pushed-in faces, or brachycephaly, and those that cause Salukis or collies to have narrow, elongated snouts, or dolichocephaly.

Source:  Genetics Society of America media release

What’s the diff, Cliff?

Cliff, a Beagle, is a specially trained detector dog working in two Dutch teaching hospitals.  He’s been the centre of a major study into detection of Clostridium difficile (‘C diff’ for those who are professionals in the field), an infectious bacteria that can run rampant through hospitals, rest homes and other healthcare facilities.

Detector dog on hospital ward

Symptoms range from mild diarrhoea to more severe conditions like colitis. The bacterium can be transmitted through either personal contact or the environment and the testing for the bacteria is time consuming.

The research involved 300 patients, 30 which had C diff infection.  Cliff was guided along the wards by his trainer and the trainer had no idea if the person was infected or not.  Cliff was trained to sit or lie down when C diff was detected.

The Results?  Cliff was an expert at identifying infections of C diff – with around 90% accuracy –  regardless of whether he was sniffing out stool samples or identifying infected patients in the hospital.  Cliff is only one dog, but with these results, the concept of using dogs to identify C diff infections has been proved.

This comprehensive video explains Cliff’s training and the research:

Source:  British Medical Journal

What’s in your dog’s plastic toy?

A research team at Texas Tech University has studied the levels of phthalates and bisphenol A (known as BPA) in dog training batons and other plastic toys.  They presented their findings at the Society of Environmental Toxicology and Chemistry conference held in California.

The research was conducted by Kimberly Wooten, a master’s student using the project as her thesis, and Phil Smith, an associate professor of terrestrial ecotoxicology.  Smith also raises and trains Labradors.

“In the process of training a lab, you do a lot of work with these plastic bumpers. I have a lot of bumpers in my garage, and they spend a lot of time in the mouths of my retrievers. Well, lots of attention has been given to chemicals in plastics lately regarding their effects on humans. Since we all care about our dogs, and we want them to be as healthy and smart and well-behaved as possible, we decided to look into this.”

BPA are used to give elasticity to plastic and vinyl and are known endocrine disruptors that mimic estrogen or act as anti-androgens and could lead to negative health effects.  In 2012, the US Government banned the use of these chemicals in baby bottles.

Training bumpers had higher levels of BPA than toys; but weathered and aged toys released more BPA than newer ones.

The research raises a number of questions, but it is hard to compare results because so few studies have been done – particularly in the area of how much of the BPA actually enters the dog’s system.

“The interaction of pet health and environmental chemicals is understudied,” Wooten said. “What may be a safe dose for one species isn’t always a good measure for another species. But the amount of BPA and phthalates we found from the bumpers would be considered on the high end of what you might find in children’s toys.”

Source:  Texas Tech University press release

Kissing your dog and the link to gum disease

My mother was never happy when our dog got too close and  managed to lick her on the mouth.   In the Snoopy cartoons, you might remember when Lucy would run around yelling ‘Get the iodine, get the hot water.  I’ve been kissed by a dog.’ 

It turns out that there is need for caution when considering the mouth-to-mouth contact with your dog.

Researchers from Japan have tracked a microbe that is very common in dogs but rare in humans.   In dog owners, 16% of them had the microbe and it appears that they share close contact with their dogs – including kissing.

The researchers also found ten human strains of periodontitis-related bacteria in the dogs’ mouths.  And they found that low levels of contact were enough to transmit mouth bacteria either way.

In considering the research, Dr Paul Maza, of the College of Veterinary Medicine at Cornell University, told America’s Fox News:  ‘Many of the different types of bacteria in dogs and cats are the same type of bacteria as in humans. If owners practice oral hygiene on their pets, such as  brushing their teeth, a pet’s mouth can actually be even cleaner than a human mouth.’

Read the full story in the Daily Mail.