Affect-Enhancing Interventions Might Lead to Longer Life

A new study examining the relationship between affect and mortality finds that older men and women with a positive state of well-being may live longer than those with a comparatively negative outlook.

Study authors Andrew Steptoe, Ph.D., and Jane Wardle, Ph.D., both professors of psychology at University College London, noted that most other studies on the subject have asked participants to assess their emotional state retrospectively. For the present study, the researchers relied on ecological momentary assessment, a “real-time” approach to collecting data on participants’ moods that allows for a greater level of accuracy.

Published online October 31, 2011, in the Proceedings of the National Academy of Sciences, the study examined the affects and mortality rates of a subset of individuals participating in the English Longitudinal Study of Aging. A total of 3,853 men and women aged 52 to 79 self-reported their mood at four intervals throughout a one-day period. Participants were then separated into three groups based on their positive affect (PA) level and followed by the researchers for an average of five years.

The group with the highest average PA had a mortality rate of 3.6 percent, compared with 4.6 percent for those in the medium-PA group and 7.3 percent for those in the low-PA group. The 50 percent difference between the high-PA and low-PA groups dropped to 35 percent after adjusting for age, gender, demographic factors, indicators of depression, presence of serious illness, and health behaviors.

In analyzing the demographics of the three groups, the researchers noted that the cohort with the highest PA included more men and married people than the other groups. And while ethnicity, employment, and education did not seem to influence individuals’ affect, members of the high-PA group were also slightly younger and wealthier than other participants.

Additionally, those with the highest PA had the greatest levels of self-rated health, despite suffering from an equal number of serious illnesses as individuals in the other two groups.

The comparative benefits associated with a high PA level remained when controlling for depression, which was evaluated using the eight-item Center for Epidemiologic Studies Depression Scale. Further, the researchers found that neither symptoms of depression nor a negative affect had a direct effect on mortality rates after adjusting for other factors.

“This suggests that, in this older general population cohort, the absence of PA may be more important to health outcomes than the presence of negative affective states,” wrote Steptoe and Wardle.

The researchers acknowledged that the study’s focus on overall mortality rates prevented them from investigating the relationship between mood and specific causes of death. Still, Steptoe and Wardle believe the study’s findings highlight a need to apply a more intense focus to the well-being of older populations.

“This study is both interesting and important,” said APA President-elect Dilip Jeste, M.D., a distinguished professor of psychiatry and neurosciences at the University of California, San Diego and an expert in geriatric psychiatry. “It has been shown previously that traits such as positive attitude toward aging, optimism, and resilience are associated with reduced mortality. While the findings of the present investigation do not establish causality, they point to the possibility that interventions seeking to enhance positive affect in older people can help lengthen lifespan in at least some individuals.”

The study was funded by grants from the U.S. National Institute on Aging and a consortium of British government departments coordinated by the U.K. Office for National Statistics. Steptoe receives funding from the British Heart Foundation. Wardle is funded by Cancer Research UK.

An abstract of “Positive Affect Measured Using Ecological Momentary Assessment and Survival in Older Men and Women” is posted at www.pnas.org/content/early/2011/10/24/1110892108.