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CE: ; JH-D-16-00744; Total nos of Pages: 7;
JH-D-16-00744
Pet ownership and survival in the elderly
hypertensive population
Enayet K. Chowdhury
a
, Mark R. Nelson
b
, Garry L.R. Jennings
c
, Lindon M.H. Wing
d
,
Christopher M. Reid
a,e
, on behalf of the ANBP2 Management Committee
Objectives: To assess the association of pet ownership
and all-cause and cardiovascular mortality over a long-term
follow-up among elderly treated hypertensive participants.
Methods: Pet-ownership data from a subcohort of the
Second Australian National Blood Pressure study were
used. Participants were aged 65–84 years at enrolment
(1995–1997) and responded to a pet-ownership
questionnaire during year 2000. Participants’ survival
information was determined over a median of 10.9 years
that includes Second Australian National Blood Pressure
in-trial period (median 4.2 years) together with posttrial
follow-up period (median 6.9 years). For the current study,
end points were any fatal cardiovascular event and all-
cause fatal events.
Results: Of those who responded to a pet-ownership
questionnaire (4039/6018 – 67%), 86% (3490/4039)
owned at least one pet at any-time during their life
(current or previous pet owner), with 36% (1456/4039)
owning at least one pet at the time of the survey. During
the follow-up period, 958 participants died including 499
deaths of cardiovascular origin. Using a Cox proportional
hazard regression model adjusting for possible
confounders, there was a 22 and 26% reduction in
cardiovascular mortality observed among previous and
current pet owners, respectively, compared with those
who had never owned one. A similar nonsignificant trend
was observed for all-cause mortality once adjusted for
potential confounders.
Conclusion: Pet ownership was associated with an
improved cardiovascular disease survival in a treated elderly
hypertensive population.
Keywords: cardiovascular events, elderly, hypertension,
pet
Abbreviation: ANBP2, Second Australian National Blood
Pressure study
INTRODUCTION
Cardiovascular disease is one of the leading causes
of death and disability accounting for about a third
of the total number of all deaths both globally and in
Australia [1,2]. In Australia, approximately 90% of these
cardiovascular deaths are in the population aged 65 years
or over. Multiple risk factors have been identified for having
a nonfatal or fatal cardiovascular event among which are
high blood pressure (BP), smoking, high serum cholesterol,
diabetes, obesity, depression, physical inactivity and social
isolation [3,4]. Reduction of high BP together with reduction
in social isolation, depression and physical inactivity can
potentially improve cardiovascular health.
Several epidemiological studies have found health
benefits from having a companion animal, although
the purpose of pet ownership may not be to enhance
health [5–7]. Owning a pet also helps people to socialize
more through interaction with other people and thus
potentially reduce stress and depression [7–10]. Dog own-
ers have been shown to have a less sedentary lifestyle, to be
more physically active and to have lower BP and choles-
terol [11,12]. Several mainly case–control studies have
shown that animal companionship is associated with
improved survival in hospitalized patients who were admit-
ted for myocardial infarction (MI) or heart failure [13,14].
However, research findings on the effect of pet owner-
ship on cardiovascular risk have been inconsistent. A cross-
sectional study conducted in an Australian population aged
40–64 years showed no evidence of an association between
pet ownership and cardiovascular events, rather a higher
DBP being observed in pet owners after adjustment for
potential confounders [15]. Another study conducted in a
US population aged 50 years or more also showed no
association between BP and pet ownership [16]. So far
there have been no large population-based studies assess-
ing the effect of pet ownership on cardiovascular outcomes.
Moreover, the majority of the studies did not include an
elderly population and mostly included only dog and/or cat
Journal of Hypertension 2016, 34:000–000
a
Centre of Cardiovascular Research & Education in Therapeutics, School of Public
Health and Preventive Medicine, Monash University, Melbourne, Victoria,
b
Menzies
Institute for Medical Research, University of Tasmania, Hobart, Tasmania,
c
Baker IDI
Heart and Diabetes Institute, Melbourne, Victoria,
d
School of Medicine, Flinders
University, Adelaide, South Australia and
e
School of Public Health, Curtin University,
Perth, Western Australia, Australia
Correspondence to Enayet K. Chowdhury, MBBS, MPH, PhD, Centre of Cardiovas-
cular Research & Education in Therapeutics, School of Public Health and Preventive
Medicine, Monash University, 6th Floor, Alfred Centre, 99 Commercial Rd, Melbourne
3004, VIC, Australia. Tel: +61 3 99030524; fax: +61 3 9903 0556;
e-mail: enayet.chowdhury@monash.edu
Received 4 August 2016 Revised 26 September 2016 Accepted 16 November 2016
J Hypertens 34:000–000 Copyright ß2016 Wolters Kluwer Health, Inc. All rights
reserved.
DOI:10.1097/HJH.0000000000001214
Journal of Hypertension www.jhypertension.com 1
Original Article
Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
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JH-D-16-00744
owners. There is also a lack of information on the associ-
ation of pet ownership and survival.
We conducted a survey among an elderly treated hyper-
tensive population participating in a clinical trial to examine
the association of pet ownership and survival over long-
term follow-up (11 years).
METHOD
Study design
We used data from a subsample of participants in the
Second Australian National Blood Pressure (ANBP2) who
responded to a pet-ownership questionnaire. ANBP2 was a
family practice-based comparative outcome trial of the
treatment of hypertension in the elderly using a PROBE
design [17]. Details about the ANBP2 study have already
been published elsewhere [17]. In brief, 6083 participants
aged between 65 and 84 years were enrolled between 1995
and 1997 from five states of Australia with an untreated BP
of at least 160 mmHg SBP and/or at least 90 mmHg DBP
before randomization.
The pet-ownership questionnaire was sent to all known
living participants in mid-2000 towards the end of the 5-year
randomized treatment (the study closed late 2001). The
questionnaire was a five-item instrument asking whether
the participant currently owned or had ever owned a pet;
the type of pet – dog, cat, bird, fish, horse or other; the
number of each type of pet currently owned; whether the
pet lived inside or outside the home; and if they were a dog
owner, whether they walked the dog daily, most days,
rarely or never.
Both the ANBP2 study and extended follow-up study
were approved by the Ethics Committee of the Royal
Australian College of General Practitioners and conducted
according to the Helsinki Declaration of the World Medical
Association. After being provided with relevant information
all participants gave written consent separately to the main
study and for extended follow-up.
Follow-up and end-points
The participants’ survival information was determined over
a median of 10.9 years (interquartile range: 10.2 –11.4) until
data were censored at 31 October 2009. This follow-up
period includes the ANBP2 clinical trial period (median 4.2
years) together with a posttrial follow-up period (median
6.9 years). During the clinical trial period a blinded inde-
pendent endpoint committee adjudicated all study end-
points, whereas posttrial survival information was
determined by linkage to the Australian Institute of Health
and Welfare National Death Index (death registry). Inter-
national Classification of Disease version 10 coding was
used to identify cause of death. For the purpose of our
study, we used any fatal cardiovascular events and any fatal
events (all-cause) as end-points. Cardiovascular fatal events
comprised sudden cardiac deaths, fatal stroke, fatal MI and
‘other’ cardiovascular causes of death.
Statistical analysis
We compared the baseline characteristics of the partici-
pants who responded to our pet questionnaire based
on pet-ownership status (never/ever/current/previous).
Differences in results for the continuous variables were
compared using analysis of variance and for the categorical
variables by the chi-squared test. Thereafter, we identified
the distribution of clinical outcome by pet-ownership
status. Finally, we used Cox-proportional hazard regression
models to compare the occurrence of fatal endpoints
(all-cause and cardiovascular) between those who ever
owned a pet (previous/current ownership) and those
who never owned one. The Cox proportional hazard
regression models that we used were unadjusted (Model
1), adjusted for age and sex (Model 2), Model 2 adjusted
for clustering of participants within family practices and
for potential baseline factors (Model 3), and Model 3 also
adjusted for in-trial factors such as average in-trial BP and
randomization to either angiotensin-converting enzyme
inhibitor or thiazide diuretic-based BP lowering medication
(Model 4). The above analyses were also repeated to
explore the association between previous and current
pet ownership with those who never owned a pet. In
addition, a subanalysis was conducted between fatal end-
points and current pet-ownership type to identify if any
association persists between owning a particular type of pet
and survival. All analyses were performed using Stata
version 11.2 for Windows (StataCorp LP, College Station,
Texas, USA).
RESULTS
Among the 6018 surviving ANBP2 participants to whom the
pet-ownership questionnaire was sent, 4039 responded
(67%) and were included in the current study. Overall
86% (3490/4039) of the respondents owned at least one
pet anytime during their life, whereas 36% (1456/4039)
owned at least one pet at the time of the survey. Among
the current pet owners, 60% (871/1456) owned at least one
dog; 35% (504/1456) owned at least one cat, 26% (374/
1456) owned at least one bird; and 11% (159/1456) owned
at least one fish. The baseline characteristics of the partici-
pants based on pet-ownership status (never/ever/current/
previous) are summarized in Table 1. The key differences
between pet owners (current/previous) and nonpet owners
are that the former are more likely to have been married or
in a de-facto relationship, less likely to be widowed,
more likely to have completed tertiary education, and more
likely to be alcohol users. In addition, current pet-owners
reported more physical activity in the 2 weeks before study
entry than did previous pet owners (Table 1). Self-reported
physical activity in the 2 weeks before study entry by
pet-ownership type is summarized in Supplementary
Table 1, http://links.lww.com/HJH/A707.
Over the long-term follow-up including both the in-trial
and the posttrial periods, 958 participants died with 499 of
these were cardiovascular deaths. Table 2 shows the distri-
bution of fatal events and mortality rates in the ANBP2
cohort by pet-ownership status. All-cause and cardiovas-
cular mortality was higher among those who never owned
a pet compared with those who currently or ever owned
a pet. With Cox-proportional hazard regression modelling,
on univariate analysis we observed a significantly lower
all-cause and cardiovascular mortality in those who ever
owned a pet (previous and/or current ownership)
Chowdhury et al.
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JH-D-16-00744
compared with those who never owned a pet (Supple-
mentary Fig. 1, http://links.lww.com/HJH/A707). On multi-
variate analysis, when adjusted for possible confounders for
outcome of interests (differences shown in Table 1), the
association (hazard ratio) between pet ownership (ever)
and reduced cardiovascular mortality [hazard ratio 0.76,
95% confidence interval (CI) 0.61–0.96, P¼0.02] remained
statistically significant but the similar association for
TABLE 1. Distribution of participants key baseline and on-treatment characteristics by pet-ownership status. Values are percentages
unless stated otherwise
Total
(N¼4039)
Never own
pet (N¼549)
Pet owner ever
(current/previous) (N¼3490)
Previous pet
owner (N¼2034)
Current pet
owner (N¼1456)
Male 49.5 53.7 48.9
a
47.0
b,a
51.4
Age, mean SD (years) 71.6 4.8 72.6 5.0 71.5 4.8
a
72.0 4.9
b,a
70.7 4.6
75 years 28.2 36.1 27.0
a
31.1
b,a
21.3
a
Marital status
Married 64.9 55.7 66.3
a
65.4
a
67.6
a
Widowed 23.7 27.7 23.0
a
24.1
a
21.5
a
Separate/divorced 5.5 5.8 5.5
a
5.1
a
6.0
a
Never married 5.5 10.6 4.6
a
4.8
a
4.4
a
De facto relationship 0.5 0.2 0.6
a
0.5
a
0.5
a
Education
Primary 21.3 26.6 20.4
a
19.5
a
21.7
a
Some high school 44.1 45.8 43.8
a
44.4
a
43.0
a
Completed high school/
university
34.7 25.6 35.8
a
36.1
a
35.3
a
Current tobacco use 5.7 5.3 5.7 5.4 6.2
Current alcohol use 74.5 70.9 75.1
a
74.5 75.8
a
BMI (mean SD, kg/m
2
) 27.2 4.1 27.1 4.1 27.2 4.1 26.94.0
b
27.5 4.2
Obese 21.2 20.3 21.4 19.5
b
24.0
SBP at randomization
(mean SD, mmHg)
167 12 168 13 167 12 16712 167 12
DBP at randomization
(mean SD, mmHg)
91 8918918918
b
92 8
Previous medical conditions
Heart disease 11.1 11.5 11.1 11.4 10.7
History of diabetes 6.6 6.0 6.7 5.7
b
8.0
Antihypertensive therapy 63.2 65.6 62.8 63.9 61.3
Laboratory values
Total cholesterol
(mean SD, mmol/l)
5.7 1.0 5.6 1.0 5.7 1.0 5.7 1.0 5.61.0
HDL Cholesterol
(mean SD, mmol/l)
1.3 0.5 1.4 0.5 1.3 0.5 1.4 0.5
b
1.3 0.5
eGFR (mean SD, ml/
min per 1.73 m
2
)
68.7 13.5 69.1 14.1 68.7 13.4 68.0 13.6
b
69.6 13.0
Physical activities (in 2 weeks before randomization)
No exercise 31.6 31.1 31.7 32.8
b
30.2
1– 6 h exercise 29.6 30.6 29.4 31.1
b
27.1
7 h 38.8 38.3 38.9 36.1
b
42.7
Randomized to receive
ACEI
50.5 49.0 50.7 50.2 51.4
On-treatment SBP
(mean SD, mmHg)
145 9 144 9 144 9 145 914510
On-treatment DBP
(mean SD, mmHg)
80 5805805805
b
81 5
a
Significant difference with those who never own pet.
b
Significant difference with current pet owner.
TABLE 2. Distribution of clinical outcome by pet ownership over long-term follow-up
Total
(N¼4039)
Non pet
owner (N¼549)
Pet owner
ever (N¼3490)
Previous pet
owner (N¼2034)
Current pet
owner (N¼1456)
Any fatal events (%) 23.7 (958) 29.5 (162) 22.8 (796)
a
23.2 (471) 22.3 (325)
a
Rate per 1000 pt-yr
(95% CI)
22.8 (21.4– 24.3) 28.9 (24.8– 33.7) 21.9 (20.4–23.5) 22.3 (20.4–24.4) 21.3 (19.1– 23.8)
Any cardiovascular
mortality (%)
12.4 (499) 16.9 (93) 11.6 (406)
a
12.3 (251) 10.7 (155)
a
Rate per 1000 pt-yr
(95% CI)
11.9 (10.9– 13.0) 16.6 (13.6– 20.4) 11.2 (10.1–12.3) 11.9 (10.5–13.4) 10.2 (8.7– 11.9)
CI, confidence interval.
a
Significant difference with those who never owned a pet.
Pet ownership and survival
Journal of Hypertension www.jhypertension.com 3
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all-cause mortality (hazard ratio 0.86, 95% CI 0.73– 1.02,
P¼0.09) failed to reach significance (Supplementary Fig. 1,
http://links.lww.com/HJH/A707).
When previous and current pet owners were separately
compared with those who had never owned a pet, current
pet owners showed a statistically significant association
with reduced cardiovascular mortality, though the
previous pet-owners failed to reach statistical significance
when adjusted for possible confounders (Table 3). When
compared with nonpet owners, there was no difference
in the relationship with all-cause mortality for either cur-
rent or previous pet owners. We observed a 22 and 26%
reduction in cardiovascular mortality among previous and
current pet owners, respectively, compared with those
who never owned a pet when adjusted for other possible
confounders. Survival curves for all-cause and cardiovas-
cular mortality by pet-ownership status (never, previous
and current) over the long-term follow-up period are
illustrated in Fig. 1.
Further subanalysis by current pet-ownership type
compared with those who never owned a pet in relation
to survival is summarized in Table 4. Overall the analysis
showed a trend for less all-cause or cardiovascular
deaths during the follow-up period with any type of pet-
ownership compared with nonpet owners, when adjusted
for potential confounders (Model 4). No significant differ-
ences were observed between individual pet categories
and mortality, suggesting any type of pet ownership was
beneficial. A secondary analysis conducted among current
dog owners showed a trend for higher mortality among
those who walked their dog rarely or never in relation to
those who walked them daily at the time of survey (Supple-
mentary Table 2, http://links.lww.com/HJH/A707).
DISCUSSION
In this study, 36% of the elderly treated hypertensive cohort
owned a pet at the time of survey, and 86% owned a pet at
TABLE 3. Effect of pet ownership status on long-term survival
Never own a pet Previous pet owner Current pet owner
Model Hazard ratio (95% confidence interval)
All-causes mortality (N¼958)
1 1.00 0.76 (0.63– 0.91) P¼0.002 0.72 (0.60 –0.87) P¼0.001
2 1.00 0.84 (0.71– 1.00) P¼0.047 0.90 (0.75 –1.09) P¼0.29
3 1.00 0.85 (0.71– 1.01) P¼0.06 0.89 (0.73– 1.08) P¼0.23
4 1.00 0.84 (0.71– 1.01) P¼0.06 0.89 (0.74– 1.08) P¼0.23
Any cardiovascular mortality (N¼499)
1 1.00 0.70 (0.55– 0.89) P¼0.004 0.60 (0.46 –0.77) P<0.001
2 1.00 0.79 (0.62– 0.99) P¼0.04 0.78 (0.61– 0.99) P¼0.04
3 1.00 0.79 (0.62– 1.01) P¼0.06 0.74 (0.57– 0.96) P¼0.02
4 1.00 0.78 (0.61– 1.00) P¼0.05 0.74 (0.57– 0.96) P¼0.02
Model 1: Unadjusted. Model 2: model 1 and adjusted for sex and age. Model 3: model 2 and adjusted for education, marital status, blood pressure at randomization, serum total
cholesterol, serum HDL, history of diabetes, smoking status, BMI, eGFR and physical activity. Model 4: model 3 and adjusted for randomized treatment group (ACE-I/diuretic) and on-
treatment blood pressure.
10.90.8
Survival
0.7
0510
Analysis time (in year) Analysis time (in year)
15 0 5 10 15
10.90.80.7
Never own pet
Currently own pet
Previosly own pet
All-cause mortality Cardiovascular mortality
Cox proportinal hazards regression
(a) (b)
FIGURE 1 Survival by pet-ownership status among elderly treated hypertensive participants
.
Adjusted for sex, age, education, marital status, blood pressure, serum total
cholesterol, serum HDL, history of diabetes, smoking status, BMI, estimated glomerular filtration rate and physical activity at baseline; and in-trial randomized treatment
group (ACE-I/diuretic) and blood pressure.
Chowdhury et al.
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any time point in their life (current/previous). This study
has shown that pet ownership at any time in life was
associated with improved survival over a period of 11 years
compared with nonpet ownership and especially with a
lower risk of fatal events of cardiovascular origin. We also
observed a trend of an association with a lower risk of fatal
events irrespective of type of pet currently owned.
There are no population level community-based data
available on the extent of pet ownership amongst elderly
Australians. However, pet ownership was reported in 57%
from a random-sampled community-based survey of 5079
Australians aged 40–64 years [15]. An Australian Compan-
ion Animal Council also reported 83% of Australians have
had a pet at some time in their lives [18], which is compar-
able with our findings. There is also limited information
available on the association between pet ownership and
health benefits among the elderly. No associations with
health benefits (physical or mental) have been reported
from a community-based sample of 2551 Australian
participants aged 60–64 years [19]. In contrast, a 1-year
longitudinal study conducted among an elderly Canadian
population (random sample 1000) aged 65–80 years
demonstrated an association between pet ownership and
improved physical health as well as a change in psycho-
social wellbeing [20]. This variation in results could be due
to difference in age range of the samples and self-assess-
ment of physical health. Among other pet-related studies, a
lower level of risk factors for cardiovascular disease has
been reported among pet owners in a clinic population of
5741 participants in Australia [21]. Another study conducted
using Australian National Survey data reported that pet
owners had less use of any medication and less frequent
visits to the general practitioner [22]. However, no specific
results have been found for the association of pet owner-
ship and subsequent mortality [23,24]. In terms of secon-
dary prevention, some studies do report a lower rate of
heart disease and longer survival among pet owners in an
established cardiovascular disease population [14,18]. In
the current study, in a population of treated elderly hyper-
tensive persons, we have extended these findings by dem-
onstrating a significantly lower cardiovascular mortality
over an 11-year period among current pet owners com-
pared with those who never owned a pet.
The underlying reason for this positive benefit of pet
ownership on survival could be due to pet-ownership
reducing the risk factors for cardiovascular disease through
the promotion of a more active lifestyle and better social
interaction [21,25]. It has also been hypothesized that pet
companionship can reduce stress and improve emotional
state that in turn can decrease central autonomic activity
and its responsiveness to stressors [26]. It has been observed
that elderly pet owners were less stressed by major adverse
life events compared with nonpet owners [20]. In addition,
improved psychosocial health associated with pet owner-
ship might have a positive impact on quick recovery
following an illness and also in reducing cardiovascular
risk factors such as serum cholesterol and BP [27]. A
reduction in BP with pet ownership has also been reported
in some previous studies [5,6]. However, in our study we
did not observe any difference in pretreatment or on-treat-
ment BP between nonpet owners and pet owners. This
difference in findings between these studies could be
because the earlier studies either did not adjust for any
or all possible confounders such as physical activity [5,6]. A
study conducted among an elderly population in the United
States also showed that pet ownership was not associated
with BP lowering or incidence of hypertension when
adjusted for age and other confounders [16]. Evidence
shows that the variation in the intensity of physical activity
(i.e. time and distance travelled) as well as achieving a
recommended level of physical activity (150 min/week)
improves cardiovascular risk factors with a lower BP and
cholesterol level [28]. In our study, we adjusted the results
for possible confounders including physical activity and
the association between pet ownership and improved
survival remained significant. We could not identify any
particularly significant explanatory factor including type of
pet ownership that could possibly explain the association
between pet ownership and reduced mortality. There is
also evidence that pet ownership can improve cognitive
function in the elderly, although we could not examine
this association in our study because of unavailability of
cognitive function data [29,30].
The current study has a number of limitations. The study
was not randomized by pet ownership, and therefore the
findings are observational in nature. Moreover, the study
was conducted in an elderly hypertensive population who
were more prone to have clinical events due to both ageing
and comorbidities. Extrapolation to the broader elderly
population is not possible from these data. In addition,
we did not have any data on the duration of pet ownership
which might be an important factor associated with
TABLE 4. Association of survival by current pet ownership type in relation to those never owned one
Current pet type No.
All-cause mortality Cardiovascular mortality
Hazard ratio (95% CI)
Hazard ratio (95% CI)
Never own pet 549 1.00 1.00
Only dog 558 0.93 (0.73– 1.19) P¼0.57 0.84 (0.60–1.19) P¼0.34
Only cat 269 0.87 (0.64– 1.18) P¼0.37 0.63 (0.40–1.01) P¼0.05
Only dog and cat 114 1.05 (0.68– 1.64) P¼0.82 0.90 (0.49–1.66) P¼0.74
Dog, cat and other pets 60 0.74 (0.37–1.50) P¼0.41 0.52 (0.19 –1.41) P¼0.20
Dog and other but no cat 139 0.96 (0.63 –1.46) P¼0.85 0.90 (0.51 – 1.58) P¼0.71
Cat and other but no dog 61 0.89 (0.50– 1.66) P¼0.72 0.55 (0.20 –1.47) P¼0.23
Other pet – no dog and cat 255 0.76 (0.56–1.05) P¼0.10 0.62 (0.39 –0.98) P¼0.04
Adjusted for sex, age, education, marital status, blood pressure, serum total cholesterol, serum HDL, history of diabetes, smoking status, BMI, estimated glomerular filtration rate and
physical activity at baseline; and in-trial randomized treatment group (ACE-I/diuretic) and blood pressure.
Pet ownership and survival
Journal of Hypertension www.jhypertension.com 5
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survival. Also, as the survey was conducted towards the end
of the randomized treatment period of the study, a potential
bias of the sample is possible due to nonresponders and
those who had died before the survey being conducted.
Finally, the subanalysis conducted by type of pet ownership
with cardiovascular mortality includes a small number of
participants by pet type. Therefore, the observed associ-
ation by type of pet ownership (i.e. ‘cat only’) with reduce
risk of cardiovascular mortality in relation to nonpet owners
might be a chance observation.
In conclusion, in this study pet ownership was associ-
ated with improved survival and lower risk of fatal cardi-
ovascular events compared with nonpet ownership among
the elderly. Keeping a pet could be used as a simple
intervention with a potential to improve survival over long
term in treated elderly hypertensive participants. Additional
prospective studies are needed to confirm that pet owner-
ship is associated with improved survival particularly from
cardiovascular diseases in a broader elderly population and
to identify whether pet-ownership type and the duration of
ownership are relevant important determinants or not.
ACKNOWLEDGEMENTS
We are indebted to the participants, study staff, data man-
agement centres and ANBP2 Management Committee. The
Management Committee consists of the following mem-
bers: L.M.H.W. (Chair), C.M.R., L.J. Beilin, M.A. Brown,
G.L.R.J., C.I. Johnston, J.J. McNeil, J.E. Marley, T.O. Morgan,
P. Ryan, J. Shaw (deceased), M.J. West and G. MacDonald.
ANBP2 study was supported by the Australian Common-
wealth Department of Health and Aging; the National
Health and Medical Research Council (NHMRC) of Australia
(grant 546272) and Merck Sharp & Dohme (Australia) Pty
Ltd. The long-term ANBP2 cohort follow-up study was
supported by an NHMRC programme grant (546272).
C.M.R. is supported by a Senior Research Fellowship from
NHMRC (grant 1045862). E.K.C. is supported by Postdoc-
toral Fellowship from Monash University, Australia. The
funders had no role in the study design, data collection and
analysis or the decision to publish.
Conflicts of interest
There are no conflicts of interest.
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Chowdhury et al.
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Reviewers’ Summary Evaluations
Reviewer 1
From a postanalysis of a large blood pressure trial, this
study provides both qualitative and quantitative evidence
of the impact of pet ownership on cardiovascular and
all-cause mortality during a decade-long follow-up
period in the elderly. The study is necessarily limited
due to the availability of quantitative data such as length
of time of pet ownership, however findings suggest
that pet ownership is to be considered as a potentially
significant factor in cardiovascular risk reduction in the
elderly. Additional useful information would have
been evidence of potential benefits of pet ownership
in relation to cognitive function. Data for this were not
available for this study.
Pet ownership and survival
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