Summary
In their article, Maugeri et al. (2019) studied the association of pet ownership, particularly dogs, with risk factors for cardiovascular disease (CVD). The research method was a random sample of residents (aged 25 to 64 years) and included 1769 people without a history of CVD. The study was conducted from January 1, 2013, to December 19, 2014 (Maugeri et al., 2019). Maugeri et al. (2019) compared sociodemographic characteristics, CVD risk factors, and CVD rates. In addition, comparing scores between pet owners and non-pet owners or dog owners and several other subgroups was central to the analysis of the study results. The advantage of the research method was that the researchers looked at the averages of the population, regardless of the specific group (for example, the elderly). Unlike other more focused articles, this study provides an overview of how dog ownership can positively impact people and reduce CVD risk.
As a result of the study, it became clear that owning a pet, especially a dog, positively affected a person’s physical condition. Pet owners, and especially dog owners, were more likely to report physical activity, diet, and blood glucose levels at ideal levels (Maugeri et al., 2019). In addition, pet owners reported low levels of smoking, resulting in higher CVH than non-pet owners (Maugeri et al., 2019). Unlike other pet owners, dog owners were likelier to report ideal levels of physical activity and diet (Maugeri et al., 2019). Thus, dog owners are more likely to receive a secondary preventive effect of CVD through exercise and diet.
The authors examine the general health characteristics of dog owners, other pet owners, and non-pet owners. Interestingly, the article talks about physical activity and diet for dog owners. However, as emphasized by the authors, activity was mainly discussed, and the relationship between pet ownership and dietary habits was not carefully evaluated.
Pet Ownership and Cardiovascular Health in the US General Population
The physical activity of dog owners and its preventive effect have been the basis of many related studies. Krittanawong et al. (2020) performed a multivariate analysis to narrow down the sample and examine how other factors affect CVD risk reduction. The advantage of the research is a targeted study of the relationship between increased physical activity in dog owners. In addition, the study considered demographic factors such as age, gender, marital status, education, and comorbidities (Krittanawong et al., 2020). Of the 42,038 participants in the National Health and Nutrition Survey, 10,905 (31%) were surveyed about pet ownership (Krittanawong et al., 2020). In summary, this study also confirmed that pet ownership is associated with a reduction in the prevalence of CVD compared with no ownership.
Unlike Maugeri et al., Krittanawong et al. (2020) also considered the impact of pets on the psycho-emotional state. Pet ownership provides emotional support, which can lead to lower blood pressure due to increased parasympathetic and decreased sympathetic nervous system activity (Krittanawong et al., 2020). The study also showed that pet ownership might improve autonomic function under psychological stress (Krittanawong et al., 2020). However, the physical activity associated with dog walking has been chiefly studied. According to the authors, this may mediate the relationship between dog ownership and health outcomes (Krittanawong et al., 2020). However, it is important to separate dog walking activities from other activities.
In addition, the teachings of Krittanawong et al. (2020) have other limitations related to study design. First, the research design is subject to inherent biases and selection bias due to the cross-sectional survey design. Whether or not someone has a pet is not randomized and, therefore, can be mixed. In addition, given the cross-sectional design, it is difficult to establish causality and identify potential confounding factors.
Dog Ownership and Cardiovascular Risk Factors
An interesting connection was also found between a dog’s breed and its owner’s health. The most effective against cardiovascular diseases are dogs of those breeds initially bred for hunting. There are various conflicting findings among scientists regarding the impact of pets, especially dogs, on CVD risk. While most researchers mentioned here believe that the positive effect is undeniable, others are conducting studies that refute this point of view. Mubanga et al. (2019), while not denying the preventive effect of dog ownership, state that it depends on the pet’s breed.
Mubanga et al. (2019) determined the breed based on the dog registered first if the owners had dogs of different breeds. Belonging to four different breed groups has been associated with a lower risk of cardiovascular disease (Mubanga et al., 2019). The authors identified this group and registered them as “active dog breeds” because these breeds also typically require a high level of physical activity. These dog breeds include terriers, pointers, hounds, and retrievers.
Mixed-breed and companion/toy owners and owners of dogs in younger age groups had a slightly increased risk of hypertension and dyslipidemia (Mubanga et al., 2019). It is consistent with previous studies regarding this group’s higher risk of myocardial infarction and stroke. The authors argue that dog walking rates may be lower in small companion/toy and mixed breed dogs compared to the “active dog breed” group, which consists of dog breeds initially bred for hunting.
Although, in addition to adjusting for age, gender, presence of children in the household, area of residence, population density, marital status, latitude of residence, and level of education, the study still has limitations. The main one is the possibility of unmeasured mixing by unmeasured socio-economic factors or pre-existing personality traits. However, the advantage of the research is the study of different types of dogs on the activity of their owners.
Dog Ownership and All-Cause Mortality in a Population Cohort in Norway
As can be seen, the trend in the research literature has focused mainly on the potential benefits of dog ownership for increased human physical activity levels mediated by dog walking. A study by Torske et al. (2017), unlike others mentioned in the paper, aimed to examine mortality rates among pet and non-pet owners. A 31% reduction in the risk of death from coronary heart disease and a 46% reduction in the risk of death from stroke was found among pet owners, but this was mainly due to the presence of cats (Torske et al., 2017). Dog owners showed a non-significant risk reduction, with HRs of 0.82 and 0.76 for heart disease and stroke deaths, respectively (Torske et al., 2017). The study was based on the analysis of NHANES data.
Torske et al. (2017) used Cox proportional hazards models to analyze the relationship between dog ownership and survival. The date of death was used as the endpoint, given the ethical considerations associated with anonymity. Torske et al. (2017) estimated the risk ratio for death in dog owners compared to a control group of people who did not own dogs. The advantage of this study is that it covers the long-term perspective of the issue. The study is one of the few epidemiological studies that have examined the long-term effects of owning dogs at risk of mortality in a large population cohort. On the other hand, the study did not consider other factors that could affect the population’s mortality rate.
Although the authors indicate a more significant impact of cats on life expectancy, the result is that dogs also positively affect CVD risk. The average age of dog owners was 5.4 years lower than that of dog owners (Torske et al., 2017). On the other hand, in contrast to Maugeri et al., a study by Torske et al. (2017) found that there were more smokers among dog owners than among people who did not own a dog. However, each study points to the preventive nature of pet ownership.
Pet Ownership and Cardiovascular Risk Reduction
Arhant-Sudhir’s et al. (2011) article is a review of the research literature, unlike to other studies presented in the paper. The advantage is that the authors could capture a broader perspective by looking at the relationship between pet ownership and various diseases. For example, Arhant-Sudhir et al. (2011) note that although there is some evidence that pet ownership may reduce the risk of hypertension, confounding variables may influence the relationship with blood pressure. The researchers also looked at the impact of having a dog in a person’s life on their stress levels. As it turned out, the response depends on whether the subject is a dog owner (Arhant-Sudhir et al., 2011). However, evidence generally shows a positive effect of pet interactions on laboratory responses to mental stress.
More clinical data or their specification is required for definitive conclusions in different areas. Thus, it is the main disadvantage of the study; this is what all the researchers presented in the paper face. Arhant-Sudhir et al. (2011) make this particularly clear when they say there is limited data on pet ownership and hyperlipidemia. Concerning diabetes, pet dogs show behavioral responses to episodes of hypoglycemia in their owners (Arhant-Sudhir et al., 2011). That allows for a warning of an impending episode of hypoglycemia. Such factors play an essential role in determining the impact of pet ownership on CVD risk.
Much of the data in the study confirms and expands on previous findings regarding pet ownership and social support for CVD patient survival. Dog owners were significantly less likely to die within 1 year than those without dogs (Arhant-Sudhir et al., 2011). Owning pets, especially dogs, appears to be beneficial to humans, and part of this benefit lies in its beneficial effects on risk factors for cardiovascular disease. While generally beneficial from a psychosocial point of view, the relationship between pet ownership and well-being is complex. It can vary across demographic and social factors, which has also been highlighted in other studies.
Survival Following an Acute Coronary Syndrom
The study by Parker et al. (2010) is the only one, among others analyzed here, that proves no relationship exists between the risks of CVD exacerbation and pet ownership. The authors conducted a longitudinal study of a large sample of patients hospitalized with acute coronary syndromes, including myocardial infarction and unstable angina (Parker et al., 2010). The assessment was conducted 12 months after the baseline interview, during which clinical status, adherence to treatment, cardiac status, readmission, and physical and psychological functioning were assessed (Parker et al., 2010). Despite the significant difference in conclusions, the study has the advantage of being long-term, although it is carried out in a risk group.
As a result, the authors concluded that there was no significant difference in rates of CVD death and readmission for dog owners compared with other owners. In contrast to other research findings, pet ownership was not associated with improved survival in this study. Nevertheless, when comparing cat and dog owners, cat ownership predicted a higher rate of death or readmission (Parker et al., 2010). The tendency for dog ownership to be associated with poor outcomes was not formally significant (Parker et al., 2010). The overall finding, however, makes it clear that increased physical activity in dog owners is a preventive effect of CVD risks.
References
Arhant-Sudhir, K., Arhant-Sudhir, R., & Sudhir, K. (2011). Pet ownership and Cardiovascular Risk Reduction: Supporting evidence, conflicting data and underlying mechanisms. Clinical and Experimental Pharmacology and Physiology, 38(11), 734–738. Web.
Krittanawong, C., Kumar, A., Wang, Z., Jneid, H., Virani, S. S., & Levine, G. N. (2020). Pet ownership and cardiovascular health in the US general population. The American Journal of Cardiology, 125(8), 1158–1161. Web.
Maugeri, A., Medina-Inojosa, J. R., Kunzova, S., Barchitta, M., Agodi, A., Vinciguerra, M., & Lopez-Jimenez, F. (2019). Dog ownership and cardiovascular health: Results from the kardiovize 2030 project. Mayo Clinic Proceedings: Innovations, Quality & Outcomes, 3(3), 268–275. Web.
Mubanga, M., Byberg, L., Egenvall, A., Sundström, J., Magnusson, P. K., Ingelsson, E., & Fall, T. (2019). Dog ownership and Cardiovascular Risk Factors: A nationwide prospective register-based Cohort Study. BMJ Open, 9(3). Web.
Parker, G. B., Gayed, A., Owen, C. A., Hyett, M. P., Hilton, T. M., & Heruc, G. A. (2010). Survival following an acute coronary syndrome: A PET theory put to the test. Acta Psychiatrica Scandinavica, 121(1), 65–70. Web.
Torske, M. O., Krokstad, S., Stamatakis, E., & Bauman, A. (2017). Dog ownership and all-cause mortality in a population cohort in Norway: The hunt study. PLOS ONE, 12(6). Web.