Affect and self-rated health: a dynamic approach with older adults.

Whether one considers one’s overall health to be excellent, poor, or somewhere in between is an important facet of health. Self-rated health (SRH) is a prospective predictor of mortality above and beyond other risk factors (e.g., Haring et al., 2011; Idler & Benyamini, 1997; Idler & Kasl, 1991; Lyyra, Heikkinen, Lyyra, & Jylha, 2006; Strawbridge & Wallhagen, 1999). Although there are occasional exceptions with regard to SRH’s incremental prediction over physical fitness or objective health (Deeg, van Zonneveld, van der Maas, & Habbema, 1989; Gander, Lee, Sui, Hebert, Hooker, & Blair, 2011; Lyrra et al., 2006), meta-analytic findings indicate an up to two-fold risk of mortality in those reporting “poor” versus “excellent” health, even after controlling for comorbidity, depression, functional status, socioeconomic status, and cognitive function (DeSalvo, Bloser, Reynolds, He, & Muntner, 2005). Although this relationship tends to be stronger in younger adults, the relationship holds in older adulthood (Benyamini, Blumstein, Lusky, & Modan, 2003; Giltay, Vollaard, & Kromhout, 2012; Kaplan, Barell, & Lusky, 1988; Strawbridge & Wallhagen, 1999). A new generation of SRH research has focused on the dynamics of SRH and its relationship to mortality. Changes in SRH are important because more recent assessments of SRH are better predictors of mortality than more remote assessments (Benyamini et al., 2003; Bopp et al., 2012; Singh-Manoux, Gueguen, Marikainen, Ferrie, Marmot, & Shipley, 2007), so a person’s state SRH may have more predictive power than trait SRH. SRH typically declines with increasing chronological age, but there are individual differences in its slope (Miller & Wolinsky, 2007; Sargent-Cox, Anstey, & Luszcz, 2010). A faster-declining SRH slope predicts mortality through its terminus at a lower state SRH (Miller & Wolinsky, 2007). Both initial SRH and premorbid decline in SRH predicted mortality and sentinel health events, including stroke, heart disease, cancer, and hip fracture, in older adults (Diehr, Williamson, Patrick, Bild, & Burke, 2001; Perera, Studenski, Chandler, & Guralnik, 2005). Therefore, a dynamic picture of SRH and its predictors is both more nuanced and powerful than a static picture. It has long been established that SRH and other subjective measures of health “assess at least two distinct sources of variance, one that is clearly health-relevant and another that is more subjective and psychological” (Watson & Pennebaker, 1989, p. 245). Although the mortality studies indicate that the “subjective and psychological” source is also health-relevant, this quote introduces the two main contributors to SRH: objective health status and subjective experience of one’s health. SRH strongly correlates with objective health. This is true of dynamic SRH as well as static SRH: In a longitudinal study of older adults, those who experienced a decline in SRH at any point in the study were also more likely to have had both new and worsening health conditions (Rodin & McAvay, 1992). Subjective experience of one’s health, on the other hand, is part of what Watson and Pennebaker (1989) call “somatopsychic distress” (p. 248), because people who are more prone to negative emotional states (i.e., are high in negative affectivity) are also more prone to subjective health complaints (Cohen et al., 1995; Costa & McCrae, 1987; Watson, 1988; Watson & Pennebaker, 1989). In daily diary studies, both trait negative affectivity and state negative affect contributed to subjective health complaints and worse SRH (Gijsbers van Wijk, Huisman, & Kolk, 1999; Watson, 1988; Winter, Lawton, Langston, Ruckdescel, & Sando, 2007). In longer-term longitudinal studies, older adults were more likely to have declining SRH when they also had increases in NA (Han & Jylha, 2006; Rodin & McAvay, 1992; Schollgen, Huxhold, & Schmiedek, 2011). Early reports indicated that proneness to positive emotional states (i.e., positive affectivity) was unrelated to subjective health (Watson & Pennebaker, 1989). However, subsequent reports found that positive affect (PA) contributed to subjective health complaints and SRH above and beyond negative affect (Andreasson, Szulkin, Unden, von Essen, Nilsson, & Lekander, in press; Gijsbers van Wijk et al., 1999; Pettit, Kline, Gencoz, Gencoz, & Joiner, 2001; Watson, 1988; Winter, Lawton, Langston, Ruckdescel, & Sando, 2007). Therefore, “somatopsychic distress” could be better called “somatopsychic affect”, as its influence on SRH is not due solely to distress. The two sources of variance in SRH – objective health and affect – have generally been treated as additive, and there have been few tests of interactions among objective health and affective influences on SRH. Studies that have tested interactions between health and demographic predictors of SRH tend to suggest stronger relationships in younger and healthier adults (Rodin & McAvay, 1992; Strawbridge & Wallhagen, 1999). With regard to affect, improvement in depressive symptoms was more likely to correlate with improvement in SRH in healthier older adults (Han & Jylha, 2006). As objective influences on physical health such as aging and disease exert increasing pressure on SRH, they potentially limit the degree to which affect influences SRH. This possibility has been raised in the related context of discrete symptoms, where obvious injury provides “distinctive and unambiguous” symptoms that are less open to perceptual and cognitive influence (Suls & Howren, 2012, p. 131). The signals that aging and disease provide about physical health may account for more of the inputs to global SRH, and subjective influences such as affect may account for relatively less input. On the other hand, the symptom perception model (Watson & Pennebaker, 1989) provides a competing hypothesis that posits that when more objective health signals are present, affect should have an amplifying effect and therefore have greater input to SRH. In this model, people with high negative or low positive affect have low thresholds for perceiving physical symptoms and sensations as problematic and distressing. In a related model (Diehl & Wahl, 2010), the combination of attentional biases associated with affect (e.g., Williams, Mathews, & MacLeod, 1996) and cues about physical aging may increase “awareness of age-related change” (Diehl & Wahl, 2010, p. 340) and result in changes in SRH. These models would therefore predict that the influence of affect on SRH should be greater when more health signals are present to be perceived and interpreted. In one study, changes in self-efficacy were more strongly associated with SRH for older adults above age 75 than those below, although changes in depression did not interact with age (Rodin & McAvay, 1992). Therefore, there is some evidence for both the zero-sum and the amplification hypotheses (Han & Jylha, 2007; Rodin & McAvay, 1992), but these studies differed in measures (depression vs. self-efficacy) and moderators (health vs. chronological age). The present study tested these competing hypotheses in the context of dynamic change in SRH, providing a comprehensive and systematic test of chronological age, disease, PA, and NA as they relate to SRH between and within people. Multi-level modeling was used in a 5-year, 11-wave longitudinal study of older adults to characterize the correlates of SRH. Older age, more chronic disease, more NA, and less PA were hypothesized to associate with poorer SRH, consistent with existing evidence. However, unlike most existing evidence, these hypothesized relationships were tested both between and within people over a period of years. Furthermore, two competing hypotheses that posit that affect should have interactive effects with regard to age and chronic disease were tested. One hypothesis frames the relationship as zero-sum: as objective inputs to SRH increase, subjective inputs decrease, and affect should have a lesser effect with older age or higher chronic disease. The other hypothesis frames the relationship as amplification: as objective inputs to SRH increase, the effect of interpreting those signals negatively or positively should also increase, and affect should have a greater effect with older age or higher chronic disease.