Psychological and physical health are often conceptualized as the absence of disease; there is less research that addresses positive psychological and physical functioning. For example, optimism has been linked with reduced disease risk and biological dysfunction, but very little research has evaluated associations with markers of healthy biological functioning. Thus, we investigated the association between two indicators of positive health: optimism and serum antioxidants.
The cross-sectional association between optimism and antioxidant concentrations was evaluated in 982 men and women from the Midlife in the United States study. Primary measures included self-reported optimism (assessed with the revised Life Orientation Test) and serum concentrations of nine different antioxidants (carotenoids and vitamin E). Regression analyses evaluated the relationship between optimism and antioxidant concentrations in models adjusted for demographics, health status, and health behaviors.
For every standard deviation increase in optimism, carotenoid concentrations increased by 3% to 13% in age-adjusted models. Controlling for demographic characteristics and health status attenuated this association. Fruit and vegetable consumption and smoking status were identified as potential pathways underlying the association between optimism and serum carotenoids. Optimism was not significantly associated with vitamin E.
Optimism was associated with greater carotenoid concentrations, and this association was partially explained by diet and smoking status. The direction of effects cannot be conclusively determined. Effects may be bidirectional given that optimists are likely to engage in health behaviors associated with more serum antioxidants, and more serum antioxidants are likely associated with better physical health that enhances optimism.
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From the Departments of Society, Human Development, and Health (J.K.B., D.R.W., L.D.K.), Nutrition (E.B.R.), and Epidemiology (E.B.R.), Harvard School of Public Health, Boston, Massachusetts; Department of African and African American Studies and Sociology (D.R.W.), Harvard University, Cambridge, Massachusetts; Channing Laboratory (E.B.R.), Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts; and Department of Psychology (C.R.) and Institute on Aging (C.R.), University of Wisconsin-Madison, Madison, Wisconsin.
Address correspondence and reprint requests to Julia K. Boehm, PhD, Department of Society, Human Development, and Health, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115. E-mail: firstname.lastname@example.org
Support for this research was provided by the Robert Wood Johnson Foundation through a grant, “Exploring the Concept of Positive Health,” to the Positive Psychology Center of the University of Pennsylvania, Martin Seligman, project director. The original Midlife in the United States study was supported by The John D. and Catherine T. MacArthur Foundation Research Network on Successful Midlife Development. Follow-up data collection was supported by the National Institute on Aging (P01-AG020166).
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Received for publication February 27, 2012; revision received August 22, 2012.