People aged 50 and older who have a strong sense of purpose in life are likely to have longer lives than their peers, according to a University of Michigan study published recently in JAMA Network Open.
The study’s authors believe that purposefulness — which they define as “a self-organizing life aim that stimulates goals” — has health benefits and should be consider a modifiable risk factor for premature death.
“We found a strong association between life purpose and mortality in the U.S.,” said Celeste Leigh Pearce, the study’s lead author and an epidemiologist at the University of Michigan, in an interview with Reuters reporter Linda Caroll. “This has also been found in a number of studies conducted in a number of populations and seems to be quite a robust association.”
How the study was done
Pearce and her colleagues analyzed data collected from people who had volunteered to participate in the University of Michigan’s Health and Retirement Study, which has been collecting health-related information on a representative sample of Americans aged 50 and older for almost three decades. The researchers specifically focused on 6,985 participants who had been randomly assigned in 2006 to fill out a psychological questionnaire that is widely accepted as an effective measure of life purpose. None had a diagnosed chronic or life-threatening illness at that time.
The questionnaire asked respondents to rank on a scale of 1 to 6 their level of agreements with statements such as, “I enjoy making plans for the future, and working to make them a reality” and “Some people wander aimlessly through life, but I am not one of them.” The respondents were placed into one of five categories based on their total scores.
The participants were then followed for five years. During that period, 776 died, mostly from heart problems. The study found that the people with the lowest life-purpose scores were twice as likely to have died than those with the highest scores. That was true even after the researchers adjusted for variables known to be associated with early death, including depression, physical activity, body-mass index, alcohol consumption and socioeconomic factors such as marital status and educational level.
The link between low life-purpose scores and early mortality was only for deaths caused by diseases of the heart and digestive system. No association was found for deaths caused by cancer or respiratory tract illnesses.
The study was not designed to figure out why having a strong life purpose might extend life. But Pearce and her co-authors note that other research has shown that a stronger purpose in life is associated with lower levels of molecules known as cytokines. High levels of cytokines are known to promote inflammation, including in the heart and blood vessels.
Limitations and implications
The study comes with caveats. The study is observational, so it can’t prove a direct cause-effect link between high life-purpose scores and a longer life. Other factors, not accounted for in the study, may also explain the results.
In addition, the participants were questioned about life purpose only once. Their responses might have been different on a different day — or as the years passed.
Still, as Pearce and her colleagues point out, their finding is in agreement with previous research on the topic. A study in Japan found, for example, that Japanese adults who reported they had ikigai (defined as “something to live for, the joy and goal of living”) were more likely to be alive seven years later than those who said they didn’t have ikigai.
“What I’m really struck by is the strength of our findings, as well as the consistency in the literature overall,” Pearce told NPR reporter Mara Gordon. “It seems quite convincing.”
“I approached this with a very skeptical eye,” she added. “I just find it so convincing that I’m developing a whole research program around it.”
FMI: You can read the study in full on the JAMA Network Open website.