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Trial registered on ANZCTR


Registration number
ACTRN12617000966392
Ethics application status
Approved
Date submitted
22/06/2017
Date registered
5/07/2017
Date last updated
21/06/2018
Type of registration
Retrospectively registered

Titles & IDs
Public title
Dog-Walking, Health and the Human-Dog Bond
Scientific title
Dog-Walking, Health and the Human-Dog Bond
Secondary ID [1] 292265 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cardiovascular disease 303784 0
Condition category
Condition code
Other 303153 303153 0 0
Research that is not of generic health relevance and not applicable to specific health categories listed above

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Brief name: Dog-Walking, Health and the Human-Dog Bond

A cross-over design will be employed where each participant will undergo 4 conditions across 4 different days, in a randomised sequence, namely:
1) walk with their dog
2) walk without their dog
3) interact with their dog whilst remaining physically inactive e.g. vocal communication, stroking, eye contact
4) spend time on their own whilst remaining physically inactive

The researcher should aim to book all 4 visits for each participant at approximately the same time of day. Time of day variation between participants will be accepted.

The participant must lie at rest on their couch or similar in the supine position for 10 minutes, with no access to smartphone or other electronic devices and no communication with other household members.

The participant and their dog (when necessary) must then complete the allocated condition for 15 minutes. The participant should wear the Polar V800 strap and watch throughout this period.

For condition 1, participants must walk with their dog at their average pace on a route familiar to both owner and dog. The researcher will accompany and observe the participant throughout each condition to ensure intervention fidelity. During the walk, the researcher must record a milestone around the half-way point of the walk. The researcher must also record the distance walked using the Strava V3 app. The route must avoid the dog’s preferential urination spot (e.g. tree, lamppost in the backyard or outside the house) by walking around the area at a 10m radius. Neither the owner nor dog should interact with other humans or dogs during the walk. The exact length of the walk (min) should be documented upon the participant’s return home.

For condition 2, participants must walk in a similar pattern and pace to condition 1. This requires the participant to include interruptions or pauses they would normally experience when walking with their dog. The participant should aim to reach the designated milestone at a similar time to condition 1. The owner should not interact with other humans or dogs during the walk or use smartphone devices. The exact length of the walk (min) should be documented upon the participant’s return home.

Upon completion of each condition, the participant must then lie supine for an additional 10 minutes.

A washout period of at least 24 hours will be employed following each condition.
Intervention code [1] 298493 0
Lifestyle
Comparator / control treatment
Conditions in which the dog owner is not with his or her dog
Control group
Active

Outcomes
Primary outcome [1] 302520 0
Changes in human oxytocin concentrations (measured using saliva samples)
Timepoint [1] 302520 0
For each condition, saliva samples will be collected following a 10-minute supine period directly before and after the condition (i.e. saliva samples will be collected directly before the start of a condition and 10 minutes after the completion of the condition).

There is a 24-hour washout period between conditions.
Primary outcome [2] 302521 0
Changes in the human-dog bond (as measured by MDORS scores)
Timepoint [2] 302521 0
The MDORS questionnaire will be administered immediately upon the researcher's arrival during the first visit.
Primary outcome [3] 302522 0
Changes in human autonomic nervous activity (as measured by changes in heart rate variability)
Timepoint [3] 302522 0
For each condition, HRV will be assessed during a 10-minute supine period before the basal salivary sample is collected and during a 10-minute supine period after the second salivary sample is collected.

There is a 24-hour washout period between conditions.
Secondary outcome [1] 336282 0
Associate MDORS scores with the intensity of the acute oxytocin response in humans (measured using saliva samples)
Timepoint [1] 336282 0
The MDORS questionnaire will be administered immediately upon the researcher's arrival during the first visit..

The MDORS score will be calculated prior to the first condition. The difference between basal and post-stimuli oxytocin concentrations in humans, following conditions 1 and 3, will be calculated and used to indicate the intensity of the acute oxytocin response.
Secondary outcome [2] 336283 0
Associate changes in HRV (measured using Polar V800 monitors) with the strength of the oxytocin response in humans (measured using saliva samples).

Timepoint [2] 336283 0
The difference between basal and post-stimuli oxytocin concentrations in humans, following conditions 1 and 3, will be calculated and used to indicate the intensity of the acute oxytocin response.

HRV will then be derived from the RR interval, as measured by the Polar V800 monitors. For each condition, HRV will be assessed during a 10-minute supine period before the basal salivary sample is collected and during a 10-minute supine period after the second salivary sample is collected.

Eligibility
Key inclusion criteria
For inclusion, the owner must:
• be 18 years or older
• live in the Sydney Metropolitan area
• have an absence of physical limitations that could prevent dog-walking
• walk their dog for at least 15 minutes, 4 or more times per week
• not currently own any other dogs
• be the primary or joint carer of the dog

The dog must:
• have an absence of physical limitations that could prevent dog-walking
• be male to facilitate urine sample collection
• be 1 year of age or greater and not having entered the last quantile of expected lifespan for its breed
• weigh between 5 kg and 32 kg
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Human:

-Cannot walk dog
-Owns other dogs

Dog:

-Cannot walk
-Is female

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Type of endpoint(s)
Statistical methods / analysis
Statistical analysis plan
Linear mixed models will be used to analyse the effect of each experimental condition on human salivary oxytocin concentrations, canine urinary oxytocin concentration and measures of human heart rate variability (HRV). Specifically, HRV will be quantified using the standard deviation of R-R intervals (SDRR), root mean square of successive differences of R-R intervals (RMSSD), absolute power of low frequency (LF) spectra, absolute power of high frequency (HF) spectra and the ratio of LF:HF power. Condition length (min), period (order of conditions) and condition speed (in condition 1 and 2 only) will be considered as fixed effects with the participant considered as a random effect. Analyses will be conducted in SPSS version 24 and p<0.05 will be considered significant.

Subgroup analysis
Human oxytocin response
Sex
Research indicates the effects of oxytocin may differ by sex. For example, exogenous oxytocin administration has markedly different effects on neural activation and behavioural responses in men and women under the same paradigm (1). Another study indicates that intranasal oxytocin produces differential effects in sympathetic nervous activity, with females displaying decreased activity and males showing increased activity (2). Previous research investigating human-dog interactions suggests the endogenous oxytocin response may also be sexually-differentiated. Two previous studies have found an increase in female owners’ oxytocin only with the oxytocin concentration of male owners showing no change or a slight decrease (3-5).
Age
Previous research suggests owners’ age may influence the human oxytocin response to canine interaction, with a negative correlation identified between owner age and oxytocin change (6).
Dog breed
Substantial differences exist between the phenotype and behavioural characteristics of individual breeds of dog. Breed specific behavioural differences are generally considered to be the result of selective breeding during breed development and origination (7). Some breeds are known to display greater affinity for human contact which could possibly influence the human oxytocin response to canine interaction.
MDORS
Endocrine parameters have been suggested to influence the strength of attachment between human and dog. As human mothers with high oxytocin concentrations have increased maternal bonding behaviours (8), it has also been hypothesised that dog owners with high oxytocin concentrations may engage in more interactive relationships with their dogs. Previous research supports this theory with various indicators of the human-dog relationship, as measured by the Monash Dog Owner Relationship Scale (MDORS), showing associations with human oxytocin concentrations. For example, in a sample of 10 female dog owners, the self-reported frequency of kissing the dog was associated with a greater oxytocin response following human-dog interaction (9).

Dog oxytocin response
Dog sex
It has been suggested that both the response to exogenous oxytocin administration and endogenous oxytocin concentrations may differ between female and male dogs. For example, intranasal oxytocin has shown to differentially effect human-directed social behaviour by sex, with only female dogs showing an increase in gazing behaviour after administration (4).
Owner sex
Owner sex has been associated with different styles of human-dog interaction. For example, females use verbal communication more frequently than males, with their speech more closely resembling infant-directed speech (10). Sex differences also exist in the attitudes of individuals to the use and protection of animals, with females showing higher levels of positive behaviours towards animals (11). Given the differences in attitudes and communication styles, the owners’ sex may influence the dog’s oxytocin response to interaction.
Dog age
Canine age has been associated with various behaviours. For example, age has a significant effect on boldness, with older dogs showing lower levels of boldness (12). Younger dogs have also shown an increased tendency to bite during play, whilst risk of non-play bites increases with age (13). Age-differentiated behaviour effect the style of human-dog interaction and in turn, may influence the canine endocrine response to human interaction.
Dog breed
Both genetic and epigenetic factors, which vary substantially from breed to breed, are thought to influence oxytocin in dogs (14). Genetic differences have been documented in the oxytocin receptor genes of various breeds, with associations identified between polymorphisms and human-directed social behaviours (15). Intranasal oxytocin has also shown to differentially effect different breeds of dog with Border Collies, for example, showing increased gaze towards their owner compared to German Shephard’s (14).
MDORS
Previous research has highlighted associations between specific characteristics of the human-dog relationship and the canine oxytocin response to human interaction. For example, the owner’s perceived strength of the human-dog bond has been associated with canine oxytocin, with a greater perceived human-dog bond correlated with a greater oxytocin response (9).


Heart rate variability
Sex
Substantial differences exist between males and females in measures of heart rate variability. Females display significantly lower SDRR and total power than males. They also display greater HF power and lower LF power resulting in a lower LF:HF ratio (16).
Age
Age is known to significantly effect heart rate variability, with previous research suggesting all time and frequency domain indexes of HRV decrease significantly with age (17). Another study has identified a significant decrease in total HRV power as well as LF and HF activity with increasing age (18).
MDORS
The quality and type of relationship between human and dog is likely to influence their interaction style but also the human and canine physiological responses to interaction. For example, the human endocrine response to interaction, including oxytocin and cortisol concentrations is influenced by indicators of the human-dog bond (9). Therefore, the relationship between human-dog attachment and measures of heart rate variability warrants further investigation.


References
1. Rilling JK, DeMarco AC, Hackett PD, Chen X, Gautam P, Stair S, et al. Sex differences in the neural and behavioral response to intranasal oxytocin and vasopressin during human social interaction. Psychoneuroendocrinology. 2014;39:237-48.
2. Ditzen B, Nater UM, Schaer M, La Marca R, Bodenmann G, Ehlert U, et al. Sex-specific effects of intranasal oxytocin on autonomic nervous system and emotional responses to couple conflict. Social cognitive and affective neuroscience. 2012;8(8):897-902.
3. Miller SC, Kennedy CC, DeVoe DC, Hickey M, Nelson T, Kogan L. An examination of changes in oxytocin levels in men and women before and after interaction with a bonded dog. Anthrozoös. 2009;22(1):31-42.
4. Nagasawa M, Mitsui S, En S, Ohtani N, Ohta M, Sakuma Y, et al. Oxytocin-gaze positive loop and the coevolution of human-dog bonds. Science. 2015;348(6232):333-6.
5. Kekecs Z, Szollosi A, Palfi B, Szaszi B, Kovacs KJ, Dienes Z, et al. Commentary: Oxytocin-gaze positive loop and the coevolution of human–dog bonds. Frontiers in neuroscience. 2016;10:155.
6. Nagasawa M, Kikusui T, Onaka T, Ohta M. Dog's gaze at its owner increases owner's urinary oxytocin during social interaction. Hormones and Behavior. 2009;55(3):434-41.
7. Spady TC, Ostrander EA. Canine behavioral genetics: pointing out the phenotypes and herding up the genes. The American Journal of Human Genetics. 2008;82(1):10-8.
8. Feldman R, Weller A, Zagoory-Sharon O, Levine A. Evidence for a neuroendocrinological foundation of human affiliation: plasma oxytocin levels across pregnancy and the postpartum period predict mother-infant bonding. Psychological Science. 2007;18(11):965-70.
9. Handlin L, Nilsson A, Ejdebäck M, Hydbring-Sandberg E, Uvnäs-Moberg K. Associations between the psychological characteristics of the human–dog relationship and oxytocin and cortisol levels. Anthrozoös. 2012;25(2):215-28.
10. Prato-Previde E, Fallani G, Valsecchi P. Gender differences in owners interacting with pet dogs: an observational study. Ethology. 2006;112(1):64-73.
11. Herzog HA. Gender differences in human–animal interactions: A review. Anthrozoös. 2007;20(1):7-21.
12. Starling MJ, Branson N, Thomson PC, McGreevy PD. Age, sex and reproductive status affect boldness in dogs. The Veterinary Journal. 2013;197(3):868-72.
13. Messam LM, Kass P, Chomel B, Hart L. Age-related changes in the propensity of dogs to bite. The Veterinary Journal. 2013;197(2):378-87.
14. Kovács K, Kis A, Pogány Á, Koller D, Topál J. Differential effects of oxytocin on social sensitivity in two distinct breeds of dogs (Canis familiaris). Psychoneuroendocrinology. 2016;74:212-20.
15. Kis A, Bence M, Lakatos G, Pergel E, Turcsán B, Pluijmakers J, et al. Oxytocin receptor gene polymorphisms are associated with human directed social behavior in dogs (Canis familiaris). PloS one. 2014;9(1):e83993.
16. Koenig J, Thayer JF. Sex differences in healthy human heart rate variability: a meta-analysis. Neuroscience & Biobehavioral Reviews. 2016;64:288-310.
17. Stein PK, Kleiger RE, Rottman JN. Differing effects of age on heart rate variability in men and women. American Journal of Cardiology. 1997;80(3):302-5.
18. Zhang J. Effect of age and sex on heart rate variability in healthy subjects. Journal of Manipulative & Physiological Therapeutics. 2007;30(5):374-9.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 296812 0
Other
Name [1] 296812 0
Anonymous Philanthropist
Address [1] 296812 0
Not available
Country [1] 296812 0
Australia
Primary sponsor type
Individual
Name
Dr. Emmanuel Stamatakis
Address
Prevention Research Collaboration
L6 West, Hub D17
Charles Perkins Centre
The University of Sydney
Camperdown, NSW
2006
Country
Australia
Secondary sponsor category [1] 295800 0
University
Name [1] 295800 0
University of Sydney
Address [1] 295800 0
Charles Perkins Centre
University of Sydney
Camperdown, NSW
2006
Country [1] 295800 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 298046 0
Human Research Ethics Committee of the University of Sydney
Ethics committee address [1] 298046 0
Ethics and Research Integrity
Margaret Telfer Building (K07)
University of Sydney
NSW 2006
Ethics committee country [1] 298046 0
Australia
Date submitted for ethics approval [1] 298046 0
20/03/2017
Approval date [1] 298046 0
05/04/2017
Ethics approval number [1] 298046 0
2017/215
Ethics committee name [2] 298047 0
Animal Ethics Committee of the University of Sydney
Ethics committee address [2] 298047 0
Ethics and Research Integrity
Margaret Telfer Building (K07)
University of Sydney
NSW 2006
Ethics committee country [2] 298047 0
Australia
Date submitted for ethics approval [2] 298047 0
16/03/2017
Approval date [2] 298047 0
01/06/2017
Ethics approval number [2] 298047 0
2017/1161

Summary
Brief summary
The primary aim of this research is to investigate the oxytocin response to owner-led dog-walking and human-dog interactions, in both humans and dogs, and to examine if variations in this response are influenced by the chronic strength of the human-dog bond. Secondly, this study aims to examine changes in human autonomic nervous system activity as a result of dog-walking and human-dog interactions, and to associate with any variations in the oxytocin response.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 1829 1829 0 0
/AnzctrAttachments/373188-AEAppCatA2017-1161.pdf (Ethics approval)
Attachments [2] 1832 1832 0 0
Attachments [3] 1835 1835 0 0
/AnzctrAttachments/373188(v22-06-2017-17-09-12)-PIS.pdf (Participant information/consent)
Attachments [4] 1836 1836 0 0
/AnzctrAttachments/373188-Consent form.pdf (Participant information/consent)

Contacts
Principal investigator
Name 75810 0
Dr Emmanuel Stamatakis
Address 75810 0
Prevention Research Collaboration
L6 West, Hub D17
Charles Perkins Centre
The University of Sydney
Camperdown, NSW
2006
Country 75810 0
Australia
Phone 75810 0
+61 2 86271867
Fax 75810 0
Email 75810 0
emmanuel.stamatakis@sydney.edu.au
Contact person for public queries
Name 75811 0
Ms Lauren Powell
Address 75811 0
Prevention Research Collaboration
L6 West, Hub D17
Charles Perkins Centre
The University of Sydney
Camperdown, NSW
2006
Country 75811 0
Australia
Phone 75811 0
+61 2 8627 5791
Fax 75811 0
Email 75811 0
lauren.powell@sydney.edu.au
Contact person for scientific queries
Name 75812 0
Dr Emmanuel Stamatakis
Address 75812 0
Prevention Research Collaboration
L6 West, Hub D17
Charles Perkins Centre
The University of Sydney
Camperdown, NSW
2006
Country 75812 0
Australia
Phone 75812 0
+61 2 86271867
Fax 75812 0
Email 75812 0
emmanuel.stamatakis@sydney.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary