A repeated measures design was used to analyze the effect of a canine interaction on salivary cortisol and immunoglobulin A (IgA) in 33 adults; 16 were pet owners and 17 were non-pet owners. Cortisol and IgA levels before and after a canine interaction (experimental) or viewing a canine movie (control) were measured by enzyme-linked immunosorbent assay and spectrophotometer. Data show a significant interaction effect for salivary cortisol in non-pet owners (p 5 0.003). Changes in IgA levels were not significant. The findings suggested that interaction with canines may help reduce the biological effects of stress that influences human health. Further studies with larger sample sizes are necessary to support these results.
Keywords: cortisol; immunoglobulin A; canine; human-canine interaction
Animals have been used for centuries to enhance human health outcomes. In 1792, an asylum in England incorporated caring for animals as a form of therapy to assist individuals with psychological issues and to cope with anxiety and stress (Bustad, 1980). Florence Nightingale was one of the earliest nurses to observe that small animals are therapeutic companions for the sick, especially long term chronic cases (Nightingale, 1860). In the 1940s, the American Red Cross brought dogs into the Pawling Air Force Convalescent Center in New York and found that the veterans working with the dogs were less stressed and more relaxed. During the 1960s, Levinson-a child psychiatrist- used animals as an adjunctive to traditional psychotherapy (Levinson, 1969). Levinson proposed that relationships with companion animals can play a significant role in mental health of humans.
There is scant but evolving literature indicating that interaction with canines may have a significant effect on stress and human health outcomes. Studies indicated that pet ownership may decrease stress. A study by Friedmann, Thomas, Stein, and Kleiger (2003) followed several patients that had suffered myocardial infarctions. It was found that pet owning patients had higher cardiac variability than non-pet owners, decreasing their risk of cardiac disease and mortality. Research supported that pet owners had one-third the mortality rate of those who did not own a pet 1 year after being discharged from a coronary care unit (Friedmann, Katcher, Lynch, & Thomas, 1980) and that pet owners were more likely to stay alive by reducing stress and improving mental health (Friedmann, 1995). People who own pets reported fewer doctor contacts over a 1-year period than people who did not own pets (Siegel, 1990). Moreover, pet owners use fewer medications for heart problems and sleeping difficulties (Headey, 1999). Animal-assisted therapy (AAT) has been found to reduce stress and anxiety levels in hospitalized patients with a psychiatric diagnosis (Barker & Dawson, 1998). Overall, these studies indicated that interactions with canines can have a positive mental and physical effect on human health outcomes.
Canines are easily obtainable and are promising as a supportive resource that may enhance health and well-being (Krause-Parello, 2008). Subsequently, pet ownership may also have an effect on cortisol and IgA levels when compared to non-pet owners. Research supported that responses to psychophysiological stimuli varies among individuals (Knopf & Pössel, 2009). A reduction in physiological response may occur after exposure to repeated stimuli. For example, a reduction in stress response may happen after habituating with a pet (Grissom & Bhatnagar, 2009) or interacting with a pet. This research serves to better understand the operant mechanisms by which canine interaction affects the stress biomarkers: salivary cortisol and IgA.
BACKGROUND AND SIGNIFICANCE
Stress and Human Health
Everyone experiences stress at one time or another whether it is caused by personal, social, or environmental stressors. Chronic stress can cause deterioration in an individual's health. …