Sunday, May 5, 2013

Live longer... on Purpose?


On a scale of 1 to 6, 6 being strongly agree, how much would you agree with the statement, “I enjoy making plans for the future and working to make them a reality”? What about, “I don’t have a good sense of what it is I’m trying to accomplish in life”? Depending on your answers to these and a number of related statements, psychologists can quantify what they call “purpose in life.” Purpose in life is a construct that philosophers have been interested in for quite some time, and now psychologists are seeking to understand how having purpose in life may influence factors such as your physical health and longevity. Luckily, one of my favorite friends and colleagues, Eric Kim, has spent his graduate training merging the fields of psychology and public health by investigating the relationship between positive psychological constructs, like purpose in life, and healthy aging. Specifically, he published a finding this year showing that purpose in life may be protective against the occurrence of stroke among retired adults.

To conduct his study he used data from an ongoing longitudinal study at the University of Michigan, the Health and Retirement Study (HRS). In 1992, researchers at the University of Michigan began enrolling volunteers (aged 50+ years) into a study on aging and health in retirement. Participants in this study were interviewed about their lives, their health, their work, and their relationships every two years until their death. To date, over 26,000 Americans have been enrolled in this study and the database has become an important source of our knowledge on the health related changes that occur in the transition to retirement in the United States. Find out more about HRS here.

Eric used this dataset to ask whether people who have higher purpose in life are less likely to suffer from strokes over time. To do this, he examined reported Purpose in Life scores for a randomly-selected, cross-section of HRS participants (Mean age = 69 years) and how those scores predicted changes in the likelihood of stroke over the next 4 years. Among the 6,739 participants in his study, 4% went on to have either a fatal or non-fatal stroke. What Eric found, was that participants who reported more purpose in life were less likely to have a stroke within the next 4 years than people who had lower purpose in life.

The skeptics among you may be thinking, “So what? People who have purpose in life are probably taking better care of themselves and that’s why they are less likely to have strokes.” You’re exactly right, but Eric was one step ahead of you. According to stroke.org, there are a number of know risk factors for stroke including: high blood pressure, high cholesterol, diabetes, obesity, smoking, alcohol abuse, and older age. Luckily, the HRS had collected this and much more information on these participants and Eric was able to control for up to 23 factors that may be related to the occurrence of strokes, or just general physical health. Some of these factors included: age, gender, ethnicity, marital status, educational background, smoking, amount of exercise, alcohol use, hypertension, diabetes, blood pressure, BMI, heart disease, depression symptoms, anxiety symptoms, as well as a few positive psychological characteristics that may be related to high purpose in life (e.g., optimism). Statistically, he reexamined the relationship between purpose in life and the incidence of stroke over 4 years that exists once you have already accounted for the relationship between all of these other factors and having a stroke. He found that after accounting for these factors, each standard deviation increase in purpose in life equated to a 22% percent reduced likelihood of having a stroke in the following four years. More Specifically, in this study, the average purpose in life score was 4.54 (SD= 0.92). So individuals with a purpose in life score of 5.46 were 22% less likely to have a stroke in the next four years that people with average reported purpose in life while participants with a purpose in life score of 3.62 were 22% more likely to have a stroke in the next 4 years than their average purpose in life peers.

The conclusion Eric and his colleagues made about this finding is that purpose in life may be a protective factor against the occurrence of stroke and continued to discuss whether psychology and public health researchers should be working on the development of interventions aimed at increasing purpose in life for individuals who are already at risk for stroke. Some studies have already found that practicing meditation increases purpose in life, but this may not apply to all people across the lifespan. More specifically, purpose in life seems to decline in older age, but these interventions could be targeted to older age groups as a way of reducing risk for cerebrovascular events. To me, there are obvious public health and economic reasons to invest research time and resources into interventions with these goals, but the question is: how?

In order to develop effective purpose in life increasing interventions that reduce the incidence of stroke in America, we would need to understand more about how the psychological construct of purpose in life actually protects against stroke, either in retirement age specifically or across the human lifespan. We just don’t know what’s so special physiologically or biologically about purpose in life. We also just don’t understand what purpose in life really is given that high purpose in life can be related to anything from religion to care-giving to hobbies. Some researchers have begun to speculate that purpose in life may be protective in a similar way that positive emotions and optimism are. What most people don’t know is that optimism and positive moods boost the immune system and, over time, have enormous protective health benefits. 

In terms of personal implications, I would encourage you to re-read the questions at the beginning of this article. What would it take for you to be able to strongly agree with the first statement and strongly disagree with the second statement in your life today? Perhaps consider making some minor changes in that direction; now that you know your life depends on it.

Happy birthday Eric! 

Kim, E. S., Sun, J. K., Park, N., & Peterson, C. (2013). Purpose in life and reduced stroke in older adults: The health and retirement study. Journal of Psychosomatic Research.

1 comment:

  1. Excellent info, Kate. As I am well over 50, I found this to be very meaningful. Marie Copeland

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