therapy dogsDogs may play a larger role in health than realized. (Viktor Korotayev/Reuters)

Dogs have long had special standing in the medical world. Trained to see for the blind, hear for the deaf and move for the immobilized, dogs have become indispensable companions for people with disabilities.

But dogs appear to be far more than four-legged health care workers. Over the years, data on the larger role dogs play in health has trickled out from various corners of the world. One Japanese study found pet owners made 30 percent fewer visits to doctors. A Melbourne study of 6,000 people showed that owners of dogs and other pets had lower cholesterol, blood pressure and heart attack risk compared with people who didn’t have pets. Obviously, the better health of pet owners could be explained by a variety of factors, but many experts believe companion animals improve health at least in part by lowering stress.

Dogs, in particular, also have been shown to do remarkable things to improve the health of their owners. There are stories of dogs warning their owners of imminent health threats. In 2003, University of Florida researchers published a report in the journal Seizure noting that some dogs seem to have an innate ability to detect impending seizures. A 2000 report in the British Medical Journal examined case studies of dogs alerting people with diabetes of a coming hypoglycemic episode.

More recently, some studies have suggested dogs can be cancer detectors. In 2006, the medical journal Integrative Cancer Therapies reported how ordinary house dogs could identify breast and lung cancer patients by smelling their breath. A University of Maine study is testing whether dogs can sniff out ovarian cancer.

The role dogs play in medicine is celebrated in a new book, “Paws & Effect: The Healing Power of Dogs’’ (Alyson Books, 2007), which chronicles the numerous ways dogs contribute to our health. Author Sharon Sakson is a journalist and television producer, dog breeder and American Kennel Club dog-show judge. She admits to being biased about her subject matter, and she tends to write about the mundane details of dogs and their owners. Much of the evidence surrounding dogs and health is anecdotal, although Ms. Sakson includes many references to published research. The stories of service dogs are particularly impressive, as is the nascent research into dogs’ ability to detect cancer.

Ms. Sakson said she first began thinking about the link between dogs and health while reporting an earlier book on men and dogs. A few men she interviewed who had AIDS credited their dogs with playing a role in their improved health.

While Ms. Sakson says more studies are needed to show exactly what role dogs play in health, any dog owner already knows the benefits of their relationship with their pet.

“I went into it because I loved my dogs — they can do so much for our society,'’ said Ms. Sakson. “There’s no question they give us emotional support.'’