“Want to appear 10 years younger? Just buy a dog,” is the dubious claim on the Mail Online.
A study has found a link between dog ownership and increased physical activity in older adults, but how this is linked to looking younger is unclear.
Contrary to the headline, the study did not measure or mention physical appearance.
The study actually measured physical activity levels of 547 older adults in Tayside, Scotland. After taking factors such as weather, environment, medical illnesses and socioeconomic status into account, dog owners were 12% more physically active than people who did not own a dog.
The authors say that this difference was equivalent to the activity level of someone 10 years younger.
Although the study also revealed that dog owners had better general health and physical functioning, it cannot prove that this was due to owning a dog.
It should also be noted that these results are based on just 50 dog owners and so may not be generalisable to the whole population.
So it is recommended that you go for regular “walkies”, whether or not you are accompanied by a canine companion.
Where did the story come from?
The study was carried out by researchers from the University of St Andrews, the University of Dundee and the University of Newcastle and was funded by a Chief Scientist Office Scottish government grant.
The study was published in the peer-reviewed medical journal Preventive Medicine.
Like many Mail Online health stories, while the story itself was broadly accurate (though it didn’t make clear that the study cannot prove causality) the headline bore little resemblance to reality.
Regular exercise can improve flexibility and bone strength and make you feel younger, but this is not the same as “appear[ing] 10 years younger”.
It could be the case that the headline was shoehorned in due to the Mail Online’s obsession with physical appearance. The most notorious example being the so-called “Sidebar of Shame” – the list of photo captions on the right of the website, which are mainly about how celebrities look.
What kind of research was this?
This was a cross-sectional study of older adults in Scotland. It aimed to see if there was a link between owning a dog and increased activity levels. As it is a cross-sectional study, it is only able to look at one point in time therefore it cannot prove cause and effect, it can only show associations.
What did the research involve?
The researchers used data from a study called the Physical Activity Cohort Scotland (PACS). Adults over the age of 65 were recruited from 17 GP practices across Tayside in Scotland. They were randomly selected from these practices to have a sample that included people from rural, urban, deprived and less deprived areas.
People were excluded from the study if they were in residential care, wheelchair or bedbound, had cognitive impairment, or were in another study.
Of the 3,343 people invited to take part, 584 people agreed and this study used the details from 547 of them.
The study was conducted between October 2009 and February 2011. Each participant was asked to wear an accelerometer (a device, usually electrical, that measures physical movement) for seven days to record their level of physical activity. They were requested not to change their usual pattern of activity during that week. They also filled out the following questionnaires:
- Older People and Active Living (OPAL) questionnaire which included information on their housing, marital status, education level, pet ownership and chronic medical illnesses
- Hospital Anxiety and Depression Score (HADS)
- SF-36, which measures general health status
- Social Capital Questionnaire, which captures relationship networks – such as how many friends and family an individual is in regular contact with
- London Health and Fitness Questionnaire, which covers attitudes towards physical activity and past experiences of physical activity
- an item from the Extended Theory of Planned Behaviour Questionnaire, which asked them to rate how strongly they agreed or disagreed with the sentence “I intend to do 30 min of moderate-intensity physical activity on five or more days in the forthcoming week”
The researchers also collected data on weather conditions during the accelerometer use from the UK Meteorological Office as they say that “dog walking behaviour is fairly robust to inclement weather especially in a temperate climate, whereas other types of walking are not”. That is dog walkers are more likely to brave the rain than people who walk for pleasure or exercise.
They performed statistical analyses to look for associations between level of physical activity and pet ownership. They then accounted for various potential confounding factors such as their environment, medical illnesses and socioeconomic status.
What were the basic results?
The average age of the participants was 79. Fifty people (9%) owned a dog, and their average age was 77.
When no other factors were taken into account, according to the accelerometer readings, dog owners were 27% more physically active than non-dog owners. When the analysis took into account all of the environmental and medical factors, dog owners still had 12% higher levels of physical activity.
Dog owners were significantly more likely to:
- be married
- live in rural areas
- have been physically active between leaving school and being 25 years old
- have the intention to be physically active
- have perceived behavioural control
- have better general health and physical functioning
Dog owners were also less likely to have symptoms of depression.
How did the researchers interpret the results?
The researchers say that this study shows that “on average, older dog owners were 12% more active than their counterparts who did not own a dog. This difference is equivalent to the levels of PA [physical activity] between people who differ by 10 years in age”.
They suggest that “interventions to increase activity amongst older people might usefully attempt to replicate elements of the dog ownership experience”.
In an interview with the Mail, the lead researcher Dr Zhiqiang Feng, mentions the possibility of developing an app that replicates the experience of owning a dog by prompting its “owner” to take it for “walkies” at regular intervals.
Despite media claims, this study has not shown that dog owners have bodies that appear 10 years younger than people who do not own dogs.
However, it has shown a difference in physical activity between dog owners and non-dog owners of around 12%. This was reported by the authors as being the same as the difference between people who are 10 years apart in age.
It should be noted that this figure comes from the same sample of people, reported in a previous paper. It found that the accelerometry counts were highest in affluent adults aged 65 to 80, followed by deprived adults aged 65 to 80, with lowest levels in deprived adults over 80 years old.
Strengths of the study include the attempt to recruit a diverse section of the population. However there is potential bias in the population sample as only 19% of people invited to take part in the study agreed.
Therefore it may be that this sample is not representative of the whole population, but is perhaps a group of people who are more motivated or interested in physical activity. The results are also based on a sample of just 50 dog owners. It also excluded people who were in residential care, wheelchair or bedbound or had cognitive impairment, some of whom are likely to be dog owners.
The researchers attempted to account for differences in physical activity levels according to the weather at the time the accelerometer readings were taken.
However, it is not clear whether each participant wore the accelerometer at the same time of the year, which could have an effect on activity levels and ability to be outside.
Overall this study shows that being a dog owner is associated with higher levels of physical activity and general health, presumably because of the requirement to take them for walks each day, but this study cannot prove that this is the cause of the results seen.
However, it is clear that exercise and walking are beneficial to physical and mental health and should be encouraged across all age groups.
Walking just 30 minutes, five times a week, can bring considerable health benefits over time.
And, as a story we covered earlier this week suggested, it may even help lower your dementia risk.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
Mail Online, 15 July 2014
Links to the science
Preventive Medicine. Published online June 12 2014