Do Productive Activities Reduce Inflammation in Later Life?
Purpose of the Study: The study investigates whether productive activities by older adults reduce bodily inflammation, as indicated by C-reactive protein (CRP), a biomeasure associated with the risk of cardiovascular diseases.
Design and Methods: The study uses a representative survey of adults aged 57–85 from the National Social Life, Health, and Aging Project (N = 1,790). Linear regression models were used to analyze the effects of multiple roles (employment, volunteering, attending meetings, and caregiving) and the frequency of activity within each role on log values of CRP concentration (mg/L) drawn from assayed blood samples.
Results: Number of roles for productive activities was associated with lower levels of CRP net of chronic conditions, lifestyle factors, and socioeconomic resources. When specific types of activity were examined, volunteering manifested the strongest association with lower levels of inflammation, particularly in the 70+ group. There was no evidence that frequent engagement in volunteer activity was associated with heightened inflammation.
Implications: Productive activities—and frequent volunteering in particular—may protect individuals from inflammation that is associated with increased risk of hypertension and cardiovascular disease.
Considerable research reveals that the vast majority of older adults engage in productive activities, including employment, volunteering, and other forms of social participation (Morrow-Howell, Hinterlong, & Sherraden, 2001). Productive activities refer to paid or unpaid actions that make a constructive contribution to community life (Herzog, Kahn, Morgan, Jackson, & Antonucci, 1989), and many models of successful or optimal aging consider them essential to well-being in later life (Rowe & Kahn, 1997). Indeed, productive activities are widely extolled as salutary, and considerable research identifies that these activities can enhance mental (Li & Ferraro, 2005) and physical health (Morrow-Howell, Hinterlong, Rozario, & Tang, 2003) and reduce mortality risk (Pynnönen, Törnmakägas, Heikkinen, Rantanen, & Lyyra, 2012).
Despite extensive scholarly interest examining productive activities and health in later life, most studies rely upon self-reported measures of health, disability, or physician-diagnosed illnesses, each of which can be influenced by psychosocial resources or access to health care. One wonders whether productive activities exert effects on subclinical measures of biological processes that are predictive of major disease outcomes. If the relationship exists, productive activities may be a palpable way to prevent the development and onset of chronic disease.
This study attempts to explicate the "upstream" health protective effects of productive activities by studying a marker of biological risk in older adults. Specifically, we examine the link between productive activities and C-reactive protein (CRP), a measure of inflammation. CRP is a useful biomarker for this investigation because it typically rises in later life, and high levels of CRP are linked to cardiovascular diseases including heart attack (Crimmins & Vasunilashorn, 2011). The main aims of the article are twofold: (a) Identify the association between the number of roles for productive activities and inflammation; and (b) systematically examine whether the relationship between productive activity and CRP varies by the frequency of engagement within each activity.
Considerable evidence supports the claim that productive activity is beneficial to older adults' health. Research on successful aging pioneered by Rowe and Kahn (1997) points to the importance of engaging in productive activities to maintain health and well-being. Productive activity is a significant element of maintaining health and functioning, distinct from social relations or general social embeddedness. Role theory has often been used to explicate the health benefits of productive activities: volunteering or attending organized meetings provides individuals with a unique opportunity to hold a meaningful social role and remain similarly active in later life (Thoits, 2012). Because most Americans subscribe to a busy ethic and strive to engage in meaningful roles (Ekerdt, 1986), productive activities become a viable alternative for adults who typically experience multiple role transitions in later life.
Previous research has used somewhat distinct definitions of productive activities to predict health outcomes. Volunteering and paid employment are most commonly recognized as productive activities (Burr, Mutchler, & Caro, 2007; Hinterlong, 2008; Matz-Costa, Besen, James, & Pitt-Catsouphes, 2013; Musick & Wilson, 2003). Studies show that volunteering is associated with well-being, whether the outcome considered is depressive symptoms (Li & Ferraro, 2005; Musick & Wilson, 2003), self-rated health (Lum & Lightfoot, 2005), or hypertension (Tavares, Burr, & Mutchler, 2013). Employment has similar health-promoting effects in that employed men and women show virtually no decline in self-rated health and physical functioning; however, healthier people are also more likely to be employed (Ross & Mirowsky, 1995).
Caregiving is also widely recognized as an important form of productive activity (Burr et al., 2007; Hinterlong, 2008; Matz-Costa et al., 2013). The contribution of middle-aged and older caregivers generates enormous benefits for the nation and for those served. Despite a large body of research documenting caregivers' depression and worse physical health (Pinquart & Sörensen, 2003), some studies demonstrate that caregiving behaviors may improve adults' well-being (Brown, Nesse, Vinokur, & Smith, 2003). Moen, Robison, and Dempster-McClain (1995), however, found no direct effects of concurrent or past caregiving on health.
Although studied less frequently, community engagement is another component of productive activity that may have health benefits. Community engagement includes a wide range of activities such as voting, attending community meetings, and contributing financially to or holding a leadership position in a community organization (Burr, Caro, & Moorhead, 2002; Mendes De Leon, Glass, & Berkman, 2003). Some of these activities require a considerable investment of resources, but Mendes De Leon and coworkers (2003) argue for the importance of tapping activities in which older adults are commonly involved. Meeting attendance is one of the more prevalent forms of community engagement for older adults, even though it requires a commitment of time and skills (Burr et al., 2002). Few studies, however, have examined whether meeting attendance has a salutary effect on health in later life.
Health benefits from such roles in later life may accrue from the meaning attached to them, including status, influence, and emotional gratification (Moen et al., 1995; Thoits, 1986, 2012). When the types of productive activity are profiled across the life course, younger adults typically engage in roles that are related to their other statuses (e.g., parent or employee), whereas older adults are motivated by more intrinsic reasons such as their values in helping others or their interests in local community (Herzog et al., 1989; Van Willigen, 2000). Thus, the meanings and values associated with nonobligatory roles may be more salutary to health than is the case for obligatory roles. If the person feels generative by contributing to the well-being of others, the benefits are manifest in lower risk of impairment in activities of daily living and mortality (Gruenewald, Liao, & Seeman, 2012; Piliavin & Siegl, 2007).
Several theoretical and empirical studies also suggest that productive activities may be especially beneficial for older adults. Role accumulation theory suggests that multiple role occupancy is relevant in older ages because reduction rather than accumulation of roles becomes more commonplace in later life (Moen et al., 1995). Empirical studies confirm this thesis. For instance, Van Willigen (2000) used longitudinal data to demonstrate that older volunteers (aged 60 and older) are more likely than younger adults to experience additional psychological health benefits for each hour of participation. Also, Musick and Wilson (2003) reported that volunteering had a negative effect on depressive symptoms for older adults but not for those less than 65 years old. Because older adults may be more likely than younger persons to derive a psychological benefit from productive activity, one wonders whether the effect extends to physical health phenomena such as inflammatory processes.
The literature on the health benefits of productive activities in older adults has yielded several notable discoveries. Perhaps most impressive is the breadth of outcomes considered. Previous research demonstrates that productive activities among older adults are associated with better self-rated health (Hinterlong, Morrow-Howell, & Rozario, 2007; Lum & Lightfoot, 2005), fewer depressive symptoms (Thoits & Hewitt, 2001), and greater life satisfaction (Baker, Cahalin, Gerst, & Burr, 2005). Recent discoveries also reveal that productive activities reduce the risk of hypertension in Americans (Tavares et al., 2013) and the risks of institutionalization and mortality in Finnish older adults (Pynnönen et al., 2012). As Rowe and Kahn (1997) argue, productive activities have distinctive health benefits because they provide not only a sense of belonging to a group with whom one shares common interests and activities but also a unique chance to hold social roles that give purpose and meaning to life (Thoits, 2012). Building on the contributions of previous research demonstrating the health benefits of productive activities, we articulate three ways to advance the current body of research.
First, most studies of productive activities rely on self-reported measures of physical and mental health. Although self-reported measures are widely accepted as valid, investigations are warranted that examine the influence of productive activities on biological measures, which are harbingers of subsequent health problems. Indeed, the power of using biomarkers in health research is the early detection of bodily risks that might not yet register clinically.
CRP, produced in the liver, is a useful biomarker because it indicates systemic levels of inflammation and is linked to risk of heart attack, stroke, and mortality (Crimmins & Vasunilashorn, 2011). CRP is related to some modifiable cardiovascular risk factors such as smoking, physical activity, and obesity (McDade, Hawkley, & Cacioppo, 2006) but is also inversely related to social integration: Maintaining ties to a larger community and having close and supportive relationships are related lowering chronic inflammation (Loucks, Berkman, Gruenewald, & Seeman, 2006). Accordingly, CRP presents an important and novel way to explore links between productive activities and physical health in older adults.
Productive activities may, in fact, lower older adults' inflammation through multiple pathways, particularly when they select the role. One potential pathway involves stimulating healthier responses to environmental challenges or stressors. Indeed, an observational study showed that social integration is related to quicker cardiovascular recovery from a day's exertions (Evans & Steptoe, 2001). Perhaps productive activities are similarly beneficial by improving bodily response to stressors, but we are unaware of any studies that examine the link between productive activity and CRP.
Second, though the majority of existing research examines a single indicator of productive activity, some studies point to the importance of considering a more complex picture of individuals who remain active (Baker et al., 2005; Hinterlong, 2008). Because concurrent engagement in multiple activities is common, failure to consider multiple roles may be misleading because the purported salubrious effects of productivity activities might be due to a related role that is not measured.
Third, though multiple roles may be beneficial to health, the level of involvement in each role may be consequential to the purported health benefits (Matz-Costa et al., 2013). Scholarship on volunteering also points to how burnout or overcommitment can lead to termination of the volunteer role or unfavorable health outcomes (Li & Ferraro, 2006; Rotolo, 2000). Such role overload can manifest itself on inflammation in two ways. First, high level of time commitment in productive activities may offset the purported benefits (i.e., diminishing returns). Second, and more generally, it raises the question of whether the health benefits of productive activities accrue primarily by regular engagement in one role, modest engagement in multiple roles, or some combination of both. A longitudinal study of older adults included multiple roles, suggesting that both the number of roles and the amount spent engaging in each role are significant predictors of happiness (Baker et al., 2005). The current investigation examines both the number of productive activities performed by older adults and the frequency of participation within each type of activity in predicting levels of CRP.
Drawn from the extant literature, we specify four hypotheses to guide the analysis. First, we hypothesize that older adults reporting more roles of productive activity will have lower levels of inflammation, measured by C-reactive protein. Second, we hypothesize that the frequency of participation within a role is negatively related to CRP. Testing the first two hypotheses leads us to specify a third that may be referred to as a role overload hypothesis: The health benefits of productive activities accrue until the person reaches very high levels of participation in multiple roles (interaction hypothesis). Fourth, given that other studies reveal that older adults are more likely than younger adults to reap health benefits from productive activity, we hypothesize that the effect of productive activities on CRP is stronger for adults 70 or older than for those who have not yet reached 70 (interaction hypothesis; Van Willigen, 2000).
Abstract and Introduction
Abstract
Purpose of the Study: The study investigates whether productive activities by older adults reduce bodily inflammation, as indicated by C-reactive protein (CRP), a biomeasure associated with the risk of cardiovascular diseases.
Design and Methods: The study uses a representative survey of adults aged 57–85 from the National Social Life, Health, and Aging Project (N = 1,790). Linear regression models were used to analyze the effects of multiple roles (employment, volunteering, attending meetings, and caregiving) and the frequency of activity within each role on log values of CRP concentration (mg/L) drawn from assayed blood samples.
Results: Number of roles for productive activities was associated with lower levels of CRP net of chronic conditions, lifestyle factors, and socioeconomic resources. When specific types of activity were examined, volunteering manifested the strongest association with lower levels of inflammation, particularly in the 70+ group. There was no evidence that frequent engagement in volunteer activity was associated with heightened inflammation.
Implications: Productive activities—and frequent volunteering in particular—may protect individuals from inflammation that is associated with increased risk of hypertension and cardiovascular disease.
Introduction
Considerable research reveals that the vast majority of older adults engage in productive activities, including employment, volunteering, and other forms of social participation (Morrow-Howell, Hinterlong, & Sherraden, 2001). Productive activities refer to paid or unpaid actions that make a constructive contribution to community life (Herzog, Kahn, Morgan, Jackson, & Antonucci, 1989), and many models of successful or optimal aging consider them essential to well-being in later life (Rowe & Kahn, 1997). Indeed, productive activities are widely extolled as salutary, and considerable research identifies that these activities can enhance mental (Li & Ferraro, 2005) and physical health (Morrow-Howell, Hinterlong, Rozario, & Tang, 2003) and reduce mortality risk (Pynnönen, Törnmakägas, Heikkinen, Rantanen, & Lyyra, 2012).
Despite extensive scholarly interest examining productive activities and health in later life, most studies rely upon self-reported measures of health, disability, or physician-diagnosed illnesses, each of which can be influenced by psychosocial resources or access to health care. One wonders whether productive activities exert effects on subclinical measures of biological processes that are predictive of major disease outcomes. If the relationship exists, productive activities may be a palpable way to prevent the development and onset of chronic disease.
This study attempts to explicate the "upstream" health protective effects of productive activities by studying a marker of biological risk in older adults. Specifically, we examine the link between productive activities and C-reactive protein (CRP), a measure of inflammation. CRP is a useful biomarker for this investigation because it typically rises in later life, and high levels of CRP are linked to cardiovascular diseases including heart attack (Crimmins & Vasunilashorn, 2011). The main aims of the article are twofold: (a) Identify the association between the number of roles for productive activities and inflammation; and (b) systematically examine whether the relationship between productive activity and CRP varies by the frequency of engagement within each activity.
Productive Activities and Health in Later Life
Considerable evidence supports the claim that productive activity is beneficial to older adults' health. Research on successful aging pioneered by Rowe and Kahn (1997) points to the importance of engaging in productive activities to maintain health and well-being. Productive activity is a significant element of maintaining health and functioning, distinct from social relations or general social embeddedness. Role theory has often been used to explicate the health benefits of productive activities: volunteering or attending organized meetings provides individuals with a unique opportunity to hold a meaningful social role and remain similarly active in later life (Thoits, 2012). Because most Americans subscribe to a busy ethic and strive to engage in meaningful roles (Ekerdt, 1986), productive activities become a viable alternative for adults who typically experience multiple role transitions in later life.
Previous research has used somewhat distinct definitions of productive activities to predict health outcomes. Volunteering and paid employment are most commonly recognized as productive activities (Burr, Mutchler, & Caro, 2007; Hinterlong, 2008; Matz-Costa, Besen, James, & Pitt-Catsouphes, 2013; Musick & Wilson, 2003). Studies show that volunteering is associated with well-being, whether the outcome considered is depressive symptoms (Li & Ferraro, 2005; Musick & Wilson, 2003), self-rated health (Lum & Lightfoot, 2005), or hypertension (Tavares, Burr, & Mutchler, 2013). Employment has similar health-promoting effects in that employed men and women show virtually no decline in self-rated health and physical functioning; however, healthier people are also more likely to be employed (Ross & Mirowsky, 1995).
Caregiving is also widely recognized as an important form of productive activity (Burr et al., 2007; Hinterlong, 2008; Matz-Costa et al., 2013). The contribution of middle-aged and older caregivers generates enormous benefits for the nation and for those served. Despite a large body of research documenting caregivers' depression and worse physical health (Pinquart & Sörensen, 2003), some studies demonstrate that caregiving behaviors may improve adults' well-being (Brown, Nesse, Vinokur, & Smith, 2003). Moen, Robison, and Dempster-McClain (1995), however, found no direct effects of concurrent or past caregiving on health.
Although studied less frequently, community engagement is another component of productive activity that may have health benefits. Community engagement includes a wide range of activities such as voting, attending community meetings, and contributing financially to or holding a leadership position in a community organization (Burr, Caro, & Moorhead, 2002; Mendes De Leon, Glass, & Berkman, 2003). Some of these activities require a considerable investment of resources, but Mendes De Leon and coworkers (2003) argue for the importance of tapping activities in which older adults are commonly involved. Meeting attendance is one of the more prevalent forms of community engagement for older adults, even though it requires a commitment of time and skills (Burr et al., 2002). Few studies, however, have examined whether meeting attendance has a salutary effect on health in later life.
Health benefits from such roles in later life may accrue from the meaning attached to them, including status, influence, and emotional gratification (Moen et al., 1995; Thoits, 1986, 2012). When the types of productive activity are profiled across the life course, younger adults typically engage in roles that are related to their other statuses (e.g., parent or employee), whereas older adults are motivated by more intrinsic reasons such as their values in helping others or their interests in local community (Herzog et al., 1989; Van Willigen, 2000). Thus, the meanings and values associated with nonobligatory roles may be more salutary to health than is the case for obligatory roles. If the person feels generative by contributing to the well-being of others, the benefits are manifest in lower risk of impairment in activities of daily living and mortality (Gruenewald, Liao, & Seeman, 2012; Piliavin & Siegl, 2007).
Several theoretical and empirical studies also suggest that productive activities may be especially beneficial for older adults. Role accumulation theory suggests that multiple role occupancy is relevant in older ages because reduction rather than accumulation of roles becomes more commonplace in later life (Moen et al., 1995). Empirical studies confirm this thesis. For instance, Van Willigen (2000) used longitudinal data to demonstrate that older volunteers (aged 60 and older) are more likely than younger adults to experience additional psychological health benefits for each hour of participation. Also, Musick and Wilson (2003) reported that volunteering had a negative effect on depressive symptoms for older adults but not for those less than 65 years old. Because older adults may be more likely than younger persons to derive a psychological benefit from productive activity, one wonders whether the effect extends to physical health phenomena such as inflammatory processes.
Advancing the Literature
The literature on the health benefits of productive activities in older adults has yielded several notable discoveries. Perhaps most impressive is the breadth of outcomes considered. Previous research demonstrates that productive activities among older adults are associated with better self-rated health (Hinterlong, Morrow-Howell, & Rozario, 2007; Lum & Lightfoot, 2005), fewer depressive symptoms (Thoits & Hewitt, 2001), and greater life satisfaction (Baker, Cahalin, Gerst, & Burr, 2005). Recent discoveries also reveal that productive activities reduce the risk of hypertension in Americans (Tavares et al., 2013) and the risks of institutionalization and mortality in Finnish older adults (Pynnönen et al., 2012). As Rowe and Kahn (1997) argue, productive activities have distinctive health benefits because they provide not only a sense of belonging to a group with whom one shares common interests and activities but also a unique chance to hold social roles that give purpose and meaning to life (Thoits, 2012). Building on the contributions of previous research demonstrating the health benefits of productive activities, we articulate three ways to advance the current body of research.
First, most studies of productive activities rely on self-reported measures of physical and mental health. Although self-reported measures are widely accepted as valid, investigations are warranted that examine the influence of productive activities on biological measures, which are harbingers of subsequent health problems. Indeed, the power of using biomarkers in health research is the early detection of bodily risks that might not yet register clinically.
CRP, produced in the liver, is a useful biomarker because it indicates systemic levels of inflammation and is linked to risk of heart attack, stroke, and mortality (Crimmins & Vasunilashorn, 2011). CRP is related to some modifiable cardiovascular risk factors such as smoking, physical activity, and obesity (McDade, Hawkley, & Cacioppo, 2006) but is also inversely related to social integration: Maintaining ties to a larger community and having close and supportive relationships are related lowering chronic inflammation (Loucks, Berkman, Gruenewald, & Seeman, 2006). Accordingly, CRP presents an important and novel way to explore links between productive activities and physical health in older adults.
Productive activities may, in fact, lower older adults' inflammation through multiple pathways, particularly when they select the role. One potential pathway involves stimulating healthier responses to environmental challenges or stressors. Indeed, an observational study showed that social integration is related to quicker cardiovascular recovery from a day's exertions (Evans & Steptoe, 2001). Perhaps productive activities are similarly beneficial by improving bodily response to stressors, but we are unaware of any studies that examine the link between productive activity and CRP.
Second, though the majority of existing research examines a single indicator of productive activity, some studies point to the importance of considering a more complex picture of individuals who remain active (Baker et al., 2005; Hinterlong, 2008). Because concurrent engagement in multiple activities is common, failure to consider multiple roles may be misleading because the purported salubrious effects of productivity activities might be due to a related role that is not measured.
Third, though multiple roles may be beneficial to health, the level of involvement in each role may be consequential to the purported health benefits (Matz-Costa et al., 2013). Scholarship on volunteering also points to how burnout or overcommitment can lead to termination of the volunteer role or unfavorable health outcomes (Li & Ferraro, 2006; Rotolo, 2000). Such role overload can manifest itself on inflammation in two ways. First, high level of time commitment in productive activities may offset the purported benefits (i.e., diminishing returns). Second, and more generally, it raises the question of whether the health benefits of productive activities accrue primarily by regular engagement in one role, modest engagement in multiple roles, or some combination of both. A longitudinal study of older adults included multiple roles, suggesting that both the number of roles and the amount spent engaging in each role are significant predictors of happiness (Baker et al., 2005). The current investigation examines both the number of productive activities performed by older adults and the frequency of participation within each type of activity in predicting levels of CRP.
Drawn from the extant literature, we specify four hypotheses to guide the analysis. First, we hypothesize that older adults reporting more roles of productive activity will have lower levels of inflammation, measured by C-reactive protein. Second, we hypothesize that the frequency of participation within a role is negatively related to CRP. Testing the first two hypotheses leads us to specify a third that may be referred to as a role overload hypothesis: The health benefits of productive activities accrue until the person reaches very high levels of participation in multiple roles (interaction hypothesis). Fourth, given that other studies reveal that older adults are more likely than younger adults to reap health benefits from productive activity, we hypothesize that the effect of productive activities on CRP is stronger for adults 70 or older than for those who have not yet reached 70 (interaction hypothesis; Van Willigen, 2000).
Source...