We examined the association of purpose in life with mortality in >1200 community-dwelling older persons. During 5 years of follow-up, greater purpose in life was associated with a substantially reduced risk of death; more specifically, the hazard rate of a person with a high score (90th percentile) on the purpose in life measure was about 57% of the hazard rate for a person with a low score (10th percentile). The association of purpose in life with mortality did not vary by age, gender, education, or race, and the finding persisted after adjustment for several important covariates, including depressive symptoms, disability, neuroticism, the number of medical conditions, and income. The finding that purpose in life is related to longevity in older persons suggests that aspects of human flourishing—particularly the tendency to derive meaning from life's experiences and possess a sense of intentionality and goal-directedness that guides behavior—contribute to successful aging.
Importantly, although several investigators have argued that a focus on more positive factors may provide unique insights into longevity (1
), prior research examining successful or healthy aging has focused almost exclusively on the absence of disease or illness (31
). This is an important limitation of the existing research. Positive factors, such as having a sense of purpose in life, may provide a buffer against negative health outcomes, particularly in old age. In keeping with this idea, purpose in life is associated with psychological health and well-being in younger persons (5
). Although purpose in life is widely thought to be associated with other positive health outcomes, we are not aware of any prior study that has examined whether greater purpose in life is associated with a reduced risk of all-cause mortality.
Perhaps surprisingly, the association of purpose in life with mortality did not vary by age, sex, education, or race. Although prior work suggests that purpose in life is strongly associated with age, with older adults reporting lower purpose in life than younger adults (5
) (see Reker et al. (35
) for an exception), most of the available studies are cross-sectional, leaving open the question of how purpose in life changes with advancing age. Knowledge of the relation of purpose in life with other demographic characteristics is limited. In this study, men reported higher purpose than women, and Blacks reported higher purpose than Whites; it is possible that racial differences may be related to spirituality or religiosity, but we do not have data to examine that directly and other factors may be important. It also is possible that widowhood may negatively affect purpose in life among older women compared with men, but this is speculative. Nevertheless, although the reasons for these differences are unclear, our findings suggest that the association of purpose in life with mortality does not vary along demographic lines. It will be important for future studies to examine whether the association of purpose in life with mortality might be modified by other variables not measured here.
It is noteworthy that there remains some debate regarding the extent to which purpose in life may be an indicator of or proxy for depression rather than a distinct construct (5
). In our analyses, the association of purpose in life with mortality persisted even after adjustment for depressive symptoms, as well as several other potential confounders, including disability, neuroticism, the number of chronic medical conditions, and income. Whereas purpose in life was negatively correlated with depressive symptoms (r
= −.32, p
< .001), purpose in life was more strongly associated with the personality trait of neuroticism (r
= −.43, p
< .001); this may suggest that purpose in life is trait-like. Further, these findings provide some support for the construct of purpose in life and suggest that it is not merely a proxy for depression. Moreover, the results of our item-level analyses suggest that having a sense of purpose and goal-directedness in daily activities contribute to longevity. We suspect that older persons who derive purpose and meaning from life on a daily basis and who set and work toward goals may function better in aging not because they are without negative affect, but rather because they are highly engaged, focused and intentional, and participate in meaningful activities. Additionally, purpose in life in old age may involve a component of life review and it is possible that persons with higher purpose in life have a more positive view of aging or even a more positive life orientation in general. Although we think that purpose in life is important across the life span, measurement of purpose in life in older persons may reveal an enduring sense of meaningfulness and intentionality in life that may have particular relevance for age-related health outcomes. Purpose in life is potentially modifiable, and more research is needed to determine its association with other important age-related health outcomes, such as disability and Alzheimer's disease. Further, future studies should examine whether purpose in life can be enhanced in older persons, perhaps via interventions to promote goal setting and participation in personally meaningful activities as well as engagement in behaviors that will lead to the accomplishment of goals.
Importantly, the biologic basis of the association of purpose in life with mortality is unknown. One possibility is that having a greater sense of purpose in life contributes to the effective functioning of multiple biological systems (5
). If this is the case, purpose in life may help maintain optimal functioning of biological systems and thereby confer protective benefit in the face of illness or disease (5
). Although few studies have examined the link between purpose in life and indicators of physiological health, there is some evidence that psychological well-being in general, and purpose in life in particular, are associated with important biomarkers. For example, in a recent study, Ryff et al. examined the associations of six domains of well-being, including purpose in life, with multiple neuroendocrine, immune, and cardiovascular biomarkers in women aged >65 years (5
). The investigators reported significant associations between purpose life and neuroendocrine and immune markers including salivary cortisol and the proinflammatory cytokine sIL-6r, particularly among those over the age of 75 years. In addition, purpose in life was positively correlated with high-density lipoprotein cholesterol and negatively with waist/hip ratios. Purpose in life also has been shown to be negatively related to inflammatory markers in another group of older women (38
). Together, these findings extend prior work showing that psychosocial factors, such as coping and social support (39
), are linked with important disease-related biomarkers and indicate a need for future studies examining the potential biologic basis of the association of purpose in life with mortality.
This study has several strengths, including the assessment of purpose in life in a large group of community-dwelling older persons, who underwent a uniform clinical evaluation and in whom widely accepted criteria were used to exclude persons with dementia. In addition, we examined several potential confounders of the association of purpose in life with mortality. Limitations include the selected nature of the cohort, which may have restricted our range of scores on the purpose in life measure and may limit the generalizability of findings. In addition, we did not examine how purpose in life changes with age or measure some factors (e.g., religiosity) that may influence purpose in life. Future studies are needed to better understand the trajectory of purpose in life in aging and further examine the association of purpose in life with additional health outcomes.