The current research investigated the association of two different measures of positive psychological well-being – emotional vitality and optimism – with incident CHD in a middle-aged cohort. Higher levels of well-being were consistently associated with reduced risk of CHD over a mean follow-up period of 5 person-years. Notably, the association between well-being and CHD was not explained by health behaviors or biological risk factors, even though individuals with high well-being were healthier with respect to both. Moreover, the association between well-being and CHD was largely maintained after accounting for ill-being.
Similar to the findings with well-being, a relatively modest effect of ill-being on CHD risk was found in this sample, regardless of which ill-being measure was used. Given the limited measures of psychological functioning available for this study, it is possible that the attenuated effects for both well-being and ill-being when investigated simultaneously are due to the less-than-perfect measurement of both constructs. Moreover, given that neither well-being nor ill-being maintained large effects in the presence of the other, concluding that ill-being is the primary operative factor in the association between psychological health and CHD could be premature. These findings may cast new light on past work regarding the association between ill-being and CHD, as most studies have not considered ill-being in conjunction with well-being. Conclusions may differ somewhat if all studies were able to account for both ill-being and well-being, especially because other work suggests that the absence of ill-being does not necessarily imply the presence of well-being (Ryff et al., 2006
). Although it remains likely that well-being and ill-being are relatively independent, this conclusion will be strengthened with additional research that can consider both constructs within the same study, using stronger measures of psychological health.
Other results suggest that threshold effects were present such that risk of CHD was reduced at both moderate and high levels of well-being. Stratified analyses demonstrated nearly equivalent effects for men and women, as well as for younger and older individuals. Although additional analyses largely replicated the pattern of findings after separating fatal CHD and non-fatal MI from definite angina, findings were somewhat stronger for angina. Prior work has found equally strong effects of well-being with both “hard” and “soft” CHD outcomes (Kubzansky et al., 2001
), suggesting that smaller effects in the current study for fatal CHD and non-fatal MI could be due to the limited case counts available for this analysis. However, these findings should be interpreted cautiously until further replication.
Overall, the findings reported here (showing approximately 10% to 25% reduced risk of a coronary event with every unit increase in positive psychological well-being) are consistent with the magnitude of effects of these types of exposures considered in previous work (Giltay et al., 2006
; Kubzansky & Thurston, 2007
) and extend the literature by examining a cohort of mostly middle-age (rather than elderly) men and women. Although effect sizes were modest, the consistency across all analyses is notable, and the varying width of the confidence intervals is likely due to changes in power. Moreover, even after controlling for plausible risk factors, results replicated across two distinct measures of well-being and three definitions of CHD, further enhancing confidence in the findings.
One limitation of the present study concerns generalizability. Individuals in the Whitehall II cohort were from a restricted age range, were relatively healthy, and did not include blue collar workers or the unemployed. Hence, the findings may not characterize the general population. In addition, the well-being measures used in the present research have not been used previously. However, both emotional vitality and optimism demonstrated good face validity and correlations between well-being and other psychosocial factors were as expected, providing evidence for their construct validity.
Previous research with the Whitehall II cohort reported no association between positive affect – another construct within the broad category of positive psychological well-being – and incident CHD (Nabi et al., 2008
). One way to account for the discrepancy between the previous investigation and the current one is to recognize that well-being is comprised of distinct but overlapping domains: eudaimonic well-being, hedonic well-being, and social well-being (Gallagher et al., 2009
; Ryan & Deci, 2001
). Whereas emotional vitality and optimism can each be categorized as eudaimonic well-being, positive affect is categorized as hedonic well-being. Recent evidence suggests that eudaimonic and hedonic well-being have different relationships with physical health (Ryff, Singer, & Love, 2004
). Thus, distinguishing between the two (and investigating the role of interpersonal well-being) may be critical to future investigations in this area.
Despite attempts at identifying pathways by which well-being may lead to CHD, the mechanisms tested in the current investigation did not account for the relationship. It is possible that effects were not found because the measures were insufficiently precise or because change in the measures was not assessed over time. However, previous reports from the Whitehall II cohort have shown robust associations between conventional risk factors and CHD (Kivimaki et al., 2005
). Furthermore, other work has also failed to find that these factors adequately explain observed effects of well-being on CHD (Kubzansky & Thurston, 2007
; Tindle et al., 2009
). Thus, future research should consider other factors, both psychosocial and physiologic, that may mediate the relationship. For example, one of the strongest correlates of well-being is the presence of close social relationships (Diener & Seligman, 2002
). Social relationships may serve to buffer against physiological reactivity or encourage healthy behaviors, thereby reducing risk for CHD. Furthermore, other physiologically-based mechanisms not tested here may mediate the relationship. Specifically, aldosterone, heart rate, and inflammatory markers (e.g., interleukin-6, C-reactive protein, and fibrinogen) are considered risk factors for CHD and are associated with well-being (Kubzansky & Adler, 2010
; Steptoe et al., 2009
Another direction for future research is whether clinical interventions designed to boost well-being can also reduce the risk of CHD. Although interventions to alleviate distress have yielded inconsistent results for cardiovascular health (e.g., Berkman et al., 2003
), evidence suggests that focusing on positive functioning may enhance an individual’s ability to deal with challenges (Rozanski & Kubzansky, 2005
). Preliminary evidence also suggests that well-being can be sustainably increased (Seligman, Steen, Park, & Peterson, 2005
; Sheldon & Lyubomirsky, 2006
). Thus, in addition to focusing on decreasing psychological ill-being in the context of cardiovascular health, it may also be effective for clinicians to encourage the development of positive affect and cognitions, meaningful life pursuits, and personal strengths (Seligman et al., 2005
). Indeed, at least one clinical trial involving cardiac patients is currently underway to investigate whether enhancement of positive psychological well-being impacts health-related outcomes (Charlson et al., 2007
In summary, this prospective investigation of middle-aged men and women suggests that positive psychological well-being reduces risk of incident CHD, even when accounting for cardiovascular risk factors and ill-being. Although more work remains to be done regarding the pathways linking well-being to CHD, this investigation indicates that positive psychological well-being is not only an important outcome in its own right, but may have far-reaching consequences for cardiovascular health.