Fido, M.D.?

Photo by Bruteitup.

A DOG or cat owner spends roughly $10,000 on the care and feeding of his pet over its lifetime. (Dogs cost more per year, but cats make up for it by living longer.) What does he get for this investment?
Surveys indicate that what most pet owners mainly want is companionship, unconditional love and a play pal. In recent years, however, we have also begun to regard pets as furry physicians and four-legged psychotherapists.

Hal Herzog, Op-Ed in The New York Times ("Fido's No Doctor, Neither Is Whiskers")

No one would question the emotional value of pets as our companions, but can they help heal us? It depends on who you ask. Many believe so fervently, but cannot point to definitive studies that prove it. Some are skeptical, such as Hal Herzog, author of the book "Some We Love, Some We Hate, Some We Eat: Why It's So Hard To Think Straight About Animals."

There is an emerging field of study - anthrozoology, the study of how humans and pets interact and how they affect one another. Beginning in the 1980's with pioneering studies by Erika Friedmann at the University of Pennsylvania, animal-assistive therapies have been used to benefit wounded veterans among others. For more information, see the Delta Society's website. Pet companions have included not only cats and dogs, but horses as well.

Dogs have been used to reduce stress in college students and some campuses have allowed entering freshmen to live with their pets in selected dormitories.

In a recent Op-Ed in The New York Times ("Fido's No Doctor, Neither Is Whiskers"), Hal Herzog writes:

Since then, research has shown that stroking an animal lowers blood pressure, that AIDS patients living with pets are less depressed and that pet owners have lower cholesterol levels, sleep more soundly, exercise more and take fewer sick days than non-pet owners. Indeed, I have a stack of articles in my office supporting the hypothesis that pets are healthy for us.
Unfortunately, however, I also have another stack of articles, almost as high, showing that pets have either no long-term effects or have even adverse effects on physical and mental health.

Herzog goes on to describe studies that support improved health outcomes for patients with pets, those studies that either show little or no effect and those that supposedly show adverse effects:

Worse, in 2006, epidemiologists in Finland reported that pet owners were more likely than non-pet owners to suffer from sciatica, kidney disease, arthritis, migraines, panic attacks, high blood pressure and depression.

How can one sort this out?

The best approach is to consider not only the results of these studies but to look at the researchers' methods. It turns out that most studies use surveys that rely on self-reporting and do not represent bone fide clinical studies. Given the difficulty of such studies, it is not surprising that such data is lacking. One of my colleagues has taken a different, complementary approach to address how companion pets affect our health.

Dr. Krause-Parrelo, a faculty member in our School of Nursing, has dedicated her research program to understanding how pets can help improve health outcomes in vulnerable populations including the elderly, sexually abused children as well as wounded warriors (see article from USA Today). Her approach includes tools well beyond the traditional self-reporting surveys that are given to patients.

In order to understand the human-pet bond at a physiological level, Dr. Krause-Parello's research group measures hormone levels such as cortisol (a biomarker for stress levels) in patients before and after interacting with dogs. While these studies are in the preliminary stages, there are emerging trends that show a highly significant reduction in cortisol levels after patients interact with dogs, consistent with lower stress levels. As a biochemist, I will be continuing these studies with Dr. Krause-Parello and her students.

Hal Herzog's Op-Ed gives a skeptical view of whether pets offer health benefits, concluding;

But until the research is complete, pet lovers should probably keep taking their Lipitor and Prozac.

I reviewed the single study that he points to as supporting adverse effects of pet ownership in patients, carried out in Finland, and wrote the following response, published today in The New York Times:

To the Editor:

Yes, clinical studies have not yet proved health benefits of pet ownership, and more research is needed. The medical oath "First, do no harm" applies: none of the studies that Hal Herzog cites to debunk the healing pet show adverse effects.
The Finnish study, according to the authors, concluded that "pet ownership was very lightly associated with poor health" and used self-reporting -- hardly a rigorous clinical trial.
Fido may not be a doctor, but could make swallowing that pill a bit easier.

Jeffrey H. Toney
Union, N.J., Jan. 4, 2011
The writer is dean of the College of Natural, Applied and Health Sciences at Kean University.

Do you believe in the healing properties of pets, or do you think that they offer exclusively emotional benefits? Or are the two benefits somehow intertwined?