Can owning a pet really help you live longer?

Astronomer Carl Sagan famously warned that “extraordinary claims require extraordinary evidence.” I recently came across an amazing claim by Beth Frates.pet owner You are less likely to die. ”

Frates is a lifestyle physician at Harvard University's TH Chan School of Public Health, and her surprising remarks were published in a magazine. harvard magazine article. Of course, everyone dies. But can owning a pet add years to your life?

Frates' claims were based on a reliable source: a peer-reviewed paper published in the Journal of the American Heart Association. Circulation: cardiovascular quality and outcomes. In it, a research team led by Caroline Kramer from the University of Toronto reported that dog ownership was associated with a whopping 24 per cent reduction in mortality.

Too good to be true?

The idea that adopting a puppy can help you live longer is appealing, but did the study meet Sagan's extraordinary standard of evidence? This study was a meta-analysis of studies on the association between dog ownership and mortality. Meta-analysis is a statistical method in which researchers combine the results of multiple studies on the same topic. In this case, the study compared mortality rates in dog owners and non-dog owners.

The media pounced on these findings like, oh, a dog on a bone. A CBS News headline read, “Dog ownership is associated with 24% lower risk of early death.” However, the study authors made a critical error in their analysis. I didn't take into account that pet owners and non-pet owners are different. In many ways.

For example, a RAND Corporation survey of 22,000 pet owners and 19,000 non-pet owners found that pet owners tend to be younger, wealthier, and more educated than non-pet owners. Pet owners were more likely to be white, married, have children, own their own home, and be in good overall health. When the researchers incorporated these variables into their analysis, the putative benefits of pet ownership on physical health disappeared. (See “Large study finds pet owners are different.”)

Other researchers were quick to point out methodological flaws in the meta-analysis published by the American Heart Association. A team led by Adrian Baumann from the University of Sydney reanalyzed the findings used in the original paper. Their revised meta-analysis was subsequently published in the journal When including demographic and socioeconomic differences between dog owners and non-dog owners in their analysis, Broman's group found no significant association between pet ownership and mortality. .

Intrigued by these conflicting findings, I dug deeper into research on pet ownership and mortality. I searched for population-based epidemiological studies that followed owners and non-owners over time. I found nine studies of his published in peer-reviewed publications between 2010 and 2023. Comparisons of mortality rates between pet owners and non-pet owners statistically controlled for confounding variables such as gender, age, and chronic medical conditions. And the number of participants ranged from 4,000 to 3.5 million, which was huge. (The median number of study subjects was 59,342.)

The truth about pets and death

Let's arrange the research results in chronological order.

• 2010 American study – Richard Gillum and Thomas Obisesan examined survival rates in a national cohort of 11,433 American adults in the National Health Examination Survey. Over an average of eight years, people who owned both a dog and a cat were less likely to die than those who didn't own a dog.
• Australian research in 2017 – Using data from more than 4,000 participants in the Australian National Blood Pressure Study, Enayat Chaudhry and colleagues assess whether pet owners aged 65 to 67 live longer than non-pet owners. did. Over the 11-year period, 958 “fatal accidents” occurred among participants. Pet owners were less likely to die from coronary heart disease than non-owners, but as a group, pet owners did not live longer than non-owners.
• 2017 Norwegian study – Researchers from the Norwegian University of Science and Technology investigated mortality rates among more than 53,000 residents of Nord-Trøndelag County, Norway. Over 20 years, 24 percent of participants died. “We found no evidence of an association between the presence of a dog in the household and all-cause mortality,” the researchers wrote in their paper.
• 2017 Swedish study – The most powerful findings linking pet ownership and longevity come from a pair of studies by a highly regarded research group led by Tove Fall at Uppsala University. Their first study involved around 3.5 million Swedish dog owners and non-dog owners. Over 12 years, 24,000 participants died. The good news is that after controlling for variables such as gender, income, marital status, parental status, and income, dog owners had a 20 percent lower mortality rate than non-owners.
• Now, the bad news. The researchers looked at mortality rates separately for 34,000 participants in the Swedish twin registry and found different results. This is a long-term research project that will include additional information related to health and lifestyle factors. When the researchers took into account confounding variables such as body mass index, smoking, chronic medical conditions, employment status, and exercise level, dogs had no effect on mortality.
• English learning in 2018 – Researchers at the University of Sydney investigated the impact of living with a dog on survival among around 60,000 British adults who took part in the British Health Study. 8,169 people died over an average of 11 years. The researchers concluded: “In this large sample, there is no evidence of an association between living in a household with a dog and all-cause or cardiovascular disease mortality. ”
• 2018 Danish Survey – Ivar Sørensen and colleagues investigated the dog ownership status of all 46,000 Danish people aged 18 and older who died in 2015. Researchers matched each death to people who did not die during the same period based on a number of variables. Their results were mixed. While there was no “dog effect” in mortality rates for married people, dog owners without spouses had a 14 percent lower mortality rate.
• Swedish research in 2019 – A second study on dogs and mortality by Uppsala University was published in the journal 2019. Circulation (along with a flawed meta-analysis). Researchers looked at mortality rates for 180,000 people in Sweden who were hospitalized for heart attacks or strokes between 2001 and 2012. They found that dog ownership was associated with lower mortality rates for both heart disease and stroke patients. Additionally, the positive effect of dog ownership on survival was particularly pronounced for people living alone in both the heart attack and stroke groups.
• European Survey 2022 – Researchers from the University of Athens reported the results of an epidemiological study of more than 23,000 people from 21 countries who took part in the European Health, Aging and Retirement Study. During the 10-year follow-up, 5,163 of the participants died. Researchers found no difference in survival rates between pet owners and non-pet owners. (The only exception is that older women who have pet birds are more likely to die.)
• 2023 (Linköping University) Swedish Studies – Swedish researchers compared mortality rates in 8,352 dog owners registered in the Swedish National Diabetes Register with 209,993 non-dog owners. In 16 years, 18,943 people died, most of them from heart attacks. After adjusting for age and gender differences, the researchers found no difference in mortality risk between dog owners and non-dog owners.

Most studies don't find that pet owners live longer

An editorial by Dhruv Kazi of Harvard Medical School accompanied a flawed 2019 meta-analysis. Because of the discovery of a link between dog ownership and mortality, he wrote: across many countries and populationsMr. Miss, “There is no doubt that this relationship is genuine.”

However, the only population-based studies that have reported differences in mortality rates between pet owners and non-pet owners have been in Scandinavia, with two studies by the Tove Falls group in Sweden and one among unmarried dog owners. A Danish study found that the mortality rate was low. In fact, countries in the European Union where humans live longer tend to have lower rates of dog ownership, not higher rates. (For statistics geeks, r = -.42).

In an email, Fall suggested a possible explanation for these results: “Dog owners in Scandinavia may be a little more dedicated, as animal welfare laws are strict here. You're more likely to stay healthy. There are a lot of people who have publicly accessible green space here. Another aspect is that our results are primarily driven by associations of single-person households. On a global scale, Sweden has a high proportion of single-person households, which are the most common household type in the country according to Eurostat.On a European scale, Sweden ranks first on this list. Denmark is in third place.”

Does research back up the claim that pet owners are less likely to die? If we accept Carl Sagan's warning that “extraordinary claims require extraordinary evidence,” we can say that if you don't live in Scandinavia As far as I'm concerned, unfortunately the answer seems to be no.

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