The study, involving nearly 4,500 people who were followed for up to 9 years, also revealed that variability in life satisfaction across time increases risk of mortality, but only among less satisfied people.
“Although life satisfaction is typically considered relatively consistent across time, it may change in response to life circumstances such as divorce or unemployment,” said Julia Boehm, assistant professor of psychology at Chapman University.
“Some people may adapt more readily to new situations and thus appear to have relatively stable life satisfaction, and others may not adapt as quickly. If people repeatedly encounter distressing life events that diminish their life satisfaction, then fluctuations in lower levels of satisfaction seem to be particularly harmful for longevity.”
In each year of the 9-year study, older men and women responded to the question: “All things considered, how satisfied are you with your life?” Responses ranged from 0 to 10, with 10 indicating greater life satisfaction. The researchers assessed both average life satisfaction across time and the variability in life satisfaction across time. They also accounted for various other factors, including age, gender, education, health conditions, smoking status, physical activity, and depressive symptoms.
Over the course of the study, the researchers found that as participants’ life satisfaction increased, their risk of mortality was reduced by 18 percent. By contrast, greater variability in life satisfaction was associated with a 20 percent increased risk of mortality. In combination, individuals with high levels of life satisfaction tended to have reduced risk of mortality regardless of how their life satisfaction varied over time.
“This is the first study to consider the effects of life satisfaction on the risk of mortality when life satisfaction is summarized across as many as nine repeated assessments,” Boehm said. “Having multiple assessments of life satisfaction also allowed us to examine how variability in satisfaction across time might be related to longevity, which has never been investigated before.”
Taken together, the findings suggest that fluctuating levels of life satisfaction matter for mortality risk only when life satisfaction is also relatively low. Extreme variability in psychological states is often associated with mental-health disorders, so considering the variability in psychological characteristics can add insight into health-related outcomes such as longevity.
Study co-authors include Ashley Winning and Laura Kubzansky of Harvard University and Suzanne Segerstrom of the University of Kentucky.
Support for this research was provided by the Robert Wood Johnson Foundation through a grant to the Positive Psychology Center of the University of Pennsylvania (“Exploring the Concept of Positive Health,” Martin Seligman, project director). Additional support was provided by National Institute on Aging Grant K02-033629. The Household, Income and Labour Dynamics in Australia Survey was initiated and is funded by the Australian Government Department of Families, Housing, Community Services and Indigenous Affairs (FaHCSIA) and is managed by the Melbourne Institute of Applied Economic and Social Research (Melbourne Institute).
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