In a sample of 12 297 older individuals from the Nord-Trondelag Health Study – 3 (2358 pet owners), comparing dog owners, cat owners, and no pet owners, it was found that dog owners exercised more, had lower systolic blood pressure (BP), and rated their overall health as better. A later study using 12 093 participants from the same dataset found that cat owners had higher anxiety and depression scores compared with dog and nonpet owners. Interactions based on sex were observed as male cat owners had less depression than female cat owners. For pet ownership to convey health benefits, individuals need to actually spend time with their pets. A study of 928 adolescents from Australia found that pet ownership did not predict BMI, BP, health status, or quality of life. This was a healthy community sample that was likely involved in many other activities; adolescents reported to interact with their pets for only 1 day out of 10. As suggested by the authors, same-age clinical or more vulnerable populations may indeed derive greater healthy benefits from pets.[11,12] Other studies, though, have found increased physical activity in healthy adolescents who owned dogs, and that if children are attached to their dog, the probability of taking it for a walk increases. Moreover, a sample of 1097 adolescents from Australia found that adolescents who either walked or played with their dogs regularly had a greater probability of meeting national physical activity requirements.
A survey of 14 273 pregnant UK women found that dog owners (25% of sample) were 1.53 times more likely to obtain at least 3 hours a week of somewhat strenuous cardiovascular activity. This effect appeared to be specific to dog ownership and not to other pets. However, dog ownership was not associated with weight status, unlike an older study that found increases in physical activity and also lower weight among dog walkers. In a survey of dog walking in a sample of 1091 older adults (14.7% owned dogs) from the Midwest United States, dog owners who were also dog walkers engaged in more overall walking, on a more frequent basis, had more total physical activity, and higher levels of 'functional ability'. Given the cross-sectional nature of the data in many of these studies, an alternative explanation is that physically active people are simply more likely to obtain dogs as pets and/or take them for walks.
To partially circumvent the limitations of cross-sectional data, Pikhartova et al. used longitudinal regression analyses to examine loneliness in a sample of 5210 participants over the age of 50. Loneliness has been associated with reduced cognitive functioning, increases in the risk for cardiovascular disease, Alzheimer's disease, increases in physician visits, and overall poor health. In the Pikartova study, women who reported owning a pet also reported higher levels of loneliness; loneliness was also a significant predictor of pet ownership. These data suggest that the variable of loneliness may be driving pet ownership. However, another recent study employed a sample of 830 older adults who were primary care patients and found that pet owners were 36% less likely to report being lonely. Participants who lived alone and did not own a pet were most likely to report being lonely. Type of pet was not examined in this study. It was suggested that owning a pet may help compensate for low levels of various forms of social support.
Clearly, more studies are needed to better understand the nature of the relationship between dog ownership, physical activity, and health, including loneliness. In 2013, the American Heart Association reviewed relevant studies on pet ownership and hyperlipidemia, physical activity, obesity, cardiovascular reactivity, and survivability, and concluded that pet ownership (dog) is associated with a reduced cardiovascular disease risk, possibly by means of causal mechanisms. Preliminary evidence also suggests that online social networking websites might also be a valuable tool for getting dog owners to more frequently walk their dogs.
Finally, owning a dog has been associated with greater perceived well being in a convenience sample of 29 US military veterans with HIV/AIDS, greater antiretroviral drug adherence and higher CD4 cell counts in a convenience sample of 370 HIV-positive men, and a reduced probability of sudden unexplained death in epilepsy. Pet ownership in childhood is also associated with greater empathy towards animals as an adult. Pet ownership among 398 homeless youth in the Los Angeles area was associated with less depressive symptomatology and loneliness, but unfortunately owning a pet as a homeless person correlated with decreased access to community services such as shelters or job-finding services.
Curr Opin Psychiatry. 2015;28(5):386-392. © 2015 Lippincott Williams & Wilkins