Study Suggests Early-Life Exposure to Dogs May Lessen Risk of Developing Schizophrenia

Ever since humans domesticated the dog, the faithful, obedient and protective animal has provided its owner with companionship and emotional well-being. Now, a study from Johns Hopkins Medicine suggests that being around “man’s best friend” from an early age may have a health benefit as well — lessening the chance of developing schizophrenia as an adult.

And while Fido may help prevent that condition, the jury is still out on whether or not there’s any link, positive or negative, between being raised with Fluffy the cat and later developing either schizophrenia or bipolar disorder.

800 Toddler with Dog_Public Domain via Wikimedia Commons

A recent study by Johns Hopkins Medicine researchers suggests that exposure to pet dogs before the age of 13 may lessen the chance of developing schizophrenia later in life. Credit: Public domain via Wikimedia Commons

 

“Serious psychiatric disorders have been associated with alterations in the immune system linked to environmental exposures in early life, and since household pets are often among the first things with which children have close contact, it was logical for us to explore the possibilities of a connection between the two,” says Robert Yolken, M.D., chair of the Stanley Division of Pediatric Neurovirology and professor of neurovirology in pediatrics at the Johns Hopkins Children’s Center, and lead author of a research paper recently posted online in the journal PLOS One.

In the study, Yolken and colleagues at Sheppard Pratt Health System in Baltimore investigated the relationship between exposure to a household pet cat or dog during the first 12 years of life and a later diagnosis of schizophrenia or bipolar disorder. For schizophrenia, the researchers were surprised to see a statistically significant decrease in the risk of a person developing the disorder if exposed to a dog early in life. Across the entire age range studied, there was no significant link between dogs and bipolar disorder, or between cats and either psychiatric disorder.

The researchers caution that more studies are needed to confirm these findings, to search for the factors behind any strongly supported links, and to more precisely define the actual risks of developing psychiatric disorders from exposing infants and children under age 13 to pet cats and dogs.

According to the American Pet Products Association’s most recent National Pet Owners Survey, there are 94 million pet cats and 90 million pet dogs in the United States. Previous studies have identified early life exposures to pet cats and dogs as environmental factors that may alter the immune system through various means, including allergic responses, contact with zoonotic (animal) bacteria and viruses, changes in a home’s microbiome, and pet-induced stress reduction effects on human brain chemistry.

Some investigators, Yolken notes, suspect that this “immune modulation” may alter the risk of developing psychiatric disorders to which a person is genetically or otherwise predisposed.

In their current study, Yolken and colleagues looked at a population of 1,371 men and women between the ages of 18 and 65 that consisted of 396 people with schizophrenia, 381 with bipolar disorder and 594 controls. Information documented about each person included age, gender, race/ethnicity, place of birth and highest level of parental education (as a measure of socioeconomic status). Patients with schizophrenia and bipolar disorder were recruited from inpatient, day hospital and rehabilitation programs of Sheppard Pratt Health System. Control group members were recruited from the Baltimore area and were screened to rule out any current or past psychiatric disorders.

All study participants were asked if they had a household pet cat or dog or both during their first 12 years of life. Those who reported that a pet cat or dog was in their house when they were born were considered to be exposed to that animal since birth.

The relationship between the age of first household pet exposure and psychiatric diagnosis was defined using a statistical model that produces a hazard ratio — a measure over time of how often specific events (in this case, exposure to a household pet and development of a psychiatric disorder) happen in a study group compared to their frequency in a control group. A hazard ratio of 1 suggests no difference between groups, while a ratio greater than 1 indicates an increased likelihood of developing schizophrenia or bipolar disorder. Likewise, a ratio less than 1 shows a decreased chance.

Analyses were conducted for four age ranges: birth to 3, 4 to 5, 6 to 8 and 9 to 12.

Surprisingly, Yolken says, the findings suggests that people who are exposed to a pet dog before their 13th birthday are significantly less likely — as much as 24% — to be diagnosed later with schizophrenia.

“The largest apparent protective effect was found for children who had a household pet dog at birth or were first exposed after birth but before age 3,” he says.

Yolken adds that if it is assumed that the hazard ratio is an accurate reflection of relative risk, then some 840,000 cases of schizophrenia (24% of the 3.5 million people diagnosed with the disorder in the United States) might be prevented by pet dog exposure or other factors associated with pet dog exposure.

“There are several plausible explanations for this possible ‘protective’ effect from contact with dogs — perhaps something in the canine microbiome that gets passed to humans and bolsters the immune system against or subdues a genetic predisposition to schizophrenia,” Yolken says.

For bipolar disorder, the study results suggest there is no risk association, either positive or negative, with being around dogs as an infant or young child.

Overall for all ages examined, early exposure to pet cats was neutral as the study could not link felines with either an increased or decreased risk of developing schizophrenia or bipolar disorder.

“However, we did find a slightly increased risk of developing both disorders for those who were first in contact with cats between the ages of 9 and 12,” Yolken says. “This indicates that the time of exposure may be critical to whether or not it alters the risk.”

One example of a suspected pet-borne trigger for schizophrenia is the disease toxoplasmosis, a condition in which cats are the primary hosts of a parasite transmitted to humans via the animals’ feces. Pregnant women have been advised for years not to change cat litter boxes to eliminate the risk of the illness passing through the placenta to their fetuses and causing a miscarriage, stillbirth, or potentially, psychiatric disorders in a child born with the infection.

In a 2003 review paper, Yolken and colleague E. Fuller Torrey, M.D., associate director of research at the Stanley Medical Research Institute in Bethesda, Maryland, provided evidence from multiple epidemiological studies conducted since 1953 that showed there also is a statistical connection between a person exposed to the parasite that causes toxoplasmosis and an increased risk of developing schizophrenia. The researchers found that a large number of people in those studies who were diagnosed with serious psychiatric disorders, including schizophrenia, also had high levels of antibodies to the toxoplasmosis parasite.

Because of this finding and others like it, most research has focused on investigating a potential link between early exposure to cats and psychiatric disorder development. Yolken says the most recent study is among the first to consider contact with dogs as well.

“A better understanding of the mechanisms underlying the associations between pet exposure and psychiatric disorders would allow us to develop appropriate prevention and treatment strategies,” Yolken says.

Source:  John Hopkins Newsroom

Warmth and gratefulness at Christmas

I began my business over 10 years ago because I believed in the need for in-home care for dogs.  Gifts at Christmas from clients are always a surprise because I feel like I’m just doing my job.  But all are appreciated.

In this post, I share some of the gifts given to me this Christmas – and the thought that has gone into them is obvious:

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

Greetings

Gretel is a red Staffordshire Bull Terrier who receives regular massage and laser therapy.  Yesterday, her Mum took this video to show me how excited she gets when I arrive.

Gretel is a tight bundle of energy and enthusiasm and her Mum has been training her to pass her Canine Good Citizen test.

She’s a joy to work with.  If I had a tail, I would wag it when I arrive, too.

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

Top dog names for 2019

As the year draws to a close, Rover.com has published the results of its survey of pet names for 2019.

Top Female Dog Names

  1. Bella
  2. Luna
  3. Lucy
  4. Daisy
  5. Lily
  6. Zoe
  7. Lola
  8. Molly
  9. Sadie
  10. Bailey

Top Male Dog Names

  1. Max
  2. Charlie
  3. Cooper
  4. Buddy
  5. Rocky
  6. Milo
  7. Jack
  8. Bear
  9. Duke
  10. Teddy

I can attest to many of these popular names.

This week, I massaged Daisy the Miniature Schnauzer and regular client Lilly (with 2 Ls), a Cavalier King Charles Spaniel.

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

Before and after

Earlier this year, I entered a Facebook competition and won a professional photo shoot for Izzy with Little Things Photography.  This is the third time in the last few years that we have worked with a professional photographer.

One of the benefits of professional services is that they have access to editing software to smooth or remove details from photos.

This is a good example.  We were at the beach and Izzy was on her long-line which the photographer has edited out of the photo for the final print, also centering Izzy in the photo.

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

Unique Sled Dogs Helped the Inuit Thrive in the North American Arctic

Inuit sled dogs have changed little since people migrated with them to the North American Arctic across the Bering Strait from Siberia, according to researchers who have examined DNA from the dogs from that time span. The legacy of these Inuit dogs survives today in Arctic sled dogs, making them one of the last remaining descendant populations of indigenous, pre-European dog lineages in the Americas.

Inuit sled dogs

A team of Greenland sled dogs pulls in Greenland’s Disko Bay. The ancestors of these dogs arrived with the Inuit to the North American Arctic. (Courtesy/Tatiana Feuerborn)

The latest research is the result of nearly a decade’s work by University of California, Davis, researchers in anthropology and veterinary genetics, who analyzed the DNA of hundreds of dogs’ ancient skeletal remains to determine that the Inuit dog had significantly different DNA than other Arctic dogs, including malamutes and huskies.

Dogs continue to play role in Arctic communities

Qimmiit (dogs in Inuktitut) were viewed by the Inuit as particularly well-suited to long-distance hauling of people and their goods across the Arctic and consuming local resources, such as sea mammals, for food.

The unique group of dogs helped the Inuit conquer the tough terrain of the North American Arctic 2,000 years ago, researchers said. Inuit dogs are the direct ancestors of modern Arctic sled dogs, and although their appearance has continued to change over time, they continue to play an important role in Arctic communities.

Experts examined the DNA from 921 dogs and wolves who lived during the last 4,500 years. Analysis of the DNA, and the locations and time periods in which they were recovered archaeologically, shows dogs from Inuit sites occupied beginning around 2,000 years ago were genetically different from dogs already in the region.

According to Sacks “the genetic profiles of ancient dogs of the American Arctic dating to 2,000 years ago were nearly identical to those of older dogs from Siberia, but contrasted starkly with those of more ancient dogs in the Americas, providing an unusually clear and definitive picture of the canine replacement event that coincided with the expansion of Thule peoples across the American Arctic two millennia ago.”

Preserving an important history

Research confirms that native peoples maintained their own dogs. By analyzing the shape of elements from 391 dogs, the study also shows that the Inuit had larger dogs with a proportionally narrower cranium to earlier dogs belonging to pre-Inuit groups.

The National Science Foundation-funded portion of the research at UC Davis was inspired by Inuit activist and author Sheila Watt-Cloutier, who told Darwent about Inuit sled-dog culling undertaken by Canadian police in the 1950s and asked if there was a way to use scientific methods to tell the history and importance of sled dogs in the Arctic. Preservation of these distinctive Inuit dogs is likely a reflection of the highly specialized role that dogs played in both long-range transportation and daily subsistence practices in Inuit society.

The article, “Specialized sledge dogs accompanied the Inuit dispersal across the North American Arctic,” was published in the Proceedings of the Royal Society B: Biological Sciences.

Source:  UC Davis media release

Misplaced priorities (why does Giving Tuesday come last)?

When I was growing up, Thanksgiving Day was always the start of the holiday season.  In fact, Santa Claus would enter Macy’s Department Store at the end of the Thanksgiving Day parade to officially open Christmas shopping season.

The retail industry has changed a lot since then.

The 2019 holiday shopping season has officially begun with reports of traffic around every shopping mall in the area – shoppers taking advantage of Black Friday sales.  And it wasn’t just on Friday, of course.  These retail sales last the entire weekend through Monday.

Then someone came up with the idea of Small Business Saturday, contrived to help small business make some sales while customers may still have some money left to spend.

Then Cyber Monday.  Another date created by retailers to encourage people to shop online.

And at the end of the line – Giving Tuesday – a day designed to be the international day of charitable giving.  Animal shelters and re-homing agencies always need your donations and hopefully, you will have some left over.

Giving Tuesday

Giving Tuesday banner from the Michigan Humane Society

It seems to me that the priorities are backwards.  I’d rather see the Friday after Thanksgiving be the day of giving.  Give thanks and then give to others who are more in need…

(All of this focus on buying stuff does my head in)

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand