Adult Lifespan Sample Research Articles

Age and Daily Positive Events Moderate the Link Between Depressive Symptoms and Inflammation

Inflammation is a pathway underlying numerous aging-related conditions. Depression is related to elevated inflammation, whereas daily positive events have been linked to lower inflammation; these psychological experiences may interact with age to predict inflammation. The purpose of this study was to examine whether daily positive events moderate the association between depressive symptoms and inflammation in an adult lifespan sample. A sample of 343 adults ages 25-75 (55% women, 83% white) in the Midlife in the United States Refresher Study completed daily diary interviews for 8 evenings about their daily positive events. Depressive symptoms were assessed with the 20-item Center for Epidemiological Studies Depression scale, and blood samples were assayed for inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP). On average, depression scores ranged from 0 to 44 (mean = 9.31, SD = 7.80), and participants reported 1.25 (SD = .70) positive events per day (range = 0–5). Depressive symptoms and daily positive events were separately associated with higher and lower log IL-6 and CRP, respectively. Depressive symptoms, daily positive events, and age interacted such that daily positive events predicted lower IL-6 (but not CRP) among midlife and older adults who reported lower depressive symptoms, whereas positive events were not related to inflammation among younger adults. Thus, these findings suggest that the protective association between daily positive events and inflammation was blunted when depressive symptoms were elevated and for younger adults. This work has implications for understanding age variations in the role of positive experiences in depression and inflammation.

Age Differences in the Consumption and Avoidance of COVID-19 Information

Staying informed about COVID-19 is crucial to maintaining public health. Although older adults are at increased risk of complications, recent data (Global Web Index, 2020) suggest that they are less likely to seek out information about COVID-19. This is consistent with prior evidence indicating that information seeking is negatively associated with age (Mata & Nunes, 2010). However, it remains unclear whether older adults merely fail to seek information or intentionally avoid information. In response, we examined whether age is associated with general information seeking and deliberate information avoidance in the wake of the COVID-19 pandemic. Based on previous work indicating age-related shifts in motivational priorities (Carstensen, 2006) we also examined whether avoidance motives differ by age. In a pre-registered online study, an adult lifespan sample (N=500, Mage=49.90, 51% female, 67% non-Hispanic White) completed self-report measures of media consumption, information avoidance, and avoidance motives with respect to the COVID-19 pandemic. In addition, we measured behavioral information avoidance by allowing participants to opt out of receiving valid COVID-19 information. As predicted, age was associated with decreased media consumption (p<.001) and higher information avoidance about COVID-19 on the behavioral measure (p<.01). Self-reported information avoidance, in contrast, was highest among younger adults (p<.05). Further, with the exception of concerns about trustworthiness, older adults were less likely than younger adults to endorse various information avoidance motives (ps<.05). Thus, although information seeking is lower and behavioral information avoidance about COVID-19 is higher in later life, this cannot be traced to explicit intentions or select motives.

The Complex Role of Discrete Emotions in Successful Aging

Research shows that emotions play an important role in successful aging. However, previous studies have largely focused on the implications of dimensional indicators of emotion, such as positive and negative affect. This approach may fail to capture important distinctions between discrete emotions such as sadness, loneliness, calmness, and empathy that could become more or less adaptive with age. The present studies adopt a discrete emotion perspective to examine age-related changes in the consequences of different positive and negative emotions for successful aging. Drawing from an evolutionary-functionalist perspective, Haase, Wu, Verstaen, and Levenson investigate whether sadness becomes more salient and adaptive in old age using a multi-method approach. Lee, Lay, Mahmood, Graf, and Hoppmann address the seemingly contradictory consequences of loneliness by examining how state- and trait-loneliness interact to predict older adults’ prosocial behaviors. Hamm, Wrosch, Barlow, and Kunzmann use two studies to examine the diverging salience and 10-year health consequences of discrete positive emotions posited to motivate rest and recovery (calmness) or pursuit of novelty and stimulation (excitement). Barlow and Mauss study the co-occurrence of discrete emotions and their age-dependent associations with well-being using an adult lifespan sample. Finally, Wieck, Katzorreck, Gerstorf, Schilling, Lücke, and Kunzmann examine lifespan changes in the adaptive function of empathy by assessing the extent to which empathic accuracy protects against stress-reactivity as people age. This symposium thus integrates new research on the role of discrete positive and negative emotions and will contribute to a deeper understanding of the complex relationships between emotions and successful aging.

Information Avoidance in Decision Making: Do the Reasons Vary by Age?

Older adults make up the majority of the U.S. patient population and age differences in information avoidance have potential implications for their ability to participate in informed medical decision making. Meta-analytic evidence suggests that older adults seek less information before making a decision than younger adults do (Mata & Nunes, 2010). However, age differences in explicit information avoidance have yet to be quantified. We hypothesized that older adults would avoid decision-relevant information more strongly than younger adults do. We also examined the self-reported reasons for information avoidance and hypothesized that older adults would express more concern about unwanted information influencing their affect (Reed & Carstensen, 2012) and decision preferences (Mather, 2006), both of which are known predictors of information avoidance (Woolley & Risen, 2018). To test these assumptions, we conducted a pre-registered online study involving three different health-related decision scenarios. For each scenario, an adult lifespan sample (N=195, Mage=52.95, 50% female, 71% non-Hispanic White) chose to either receive or avoid information. Responses were highly correlated across scenarios and results were pooled into a single avoidance measure. Analyses indicated that concerns about consequences for decision preferences positively predicted decision avoidance (p<.001), whereas concerns about consequences for affect did not (p=.079). Contrary to predictions, older age was not significantly associated with information avoidance (p=.827). Further, self-reported concerns about the influence of unwanted information on affect and decision preferences were negatively associated with age (ps<.001). This suggests that interventions to foster pre-decisional information seeking should be tailored to the target age group.

Prefronto-Striatal Structural Connectivity Mediates Adult Age Differences in Action Selection.

In complex everyday environments, action selection is critical for optimal goal-directed behavior. This refers to the process of choosing a proper action from the range of possible alternatives. The neural mechanisms underlying action selection and how these are affected by normal aging remain to be elucidated. In the present cross-sectional study, we studied processes of effector selection during a multilimb reaction time task in a lifespan sample of healthy human adults (N = 89; 20-75 years; 48 males, 41 females). Participants were instructed to react as quickly and accurately as possible to visually cued stimuli representing single-limb or combined upper and/or lower limb motions. Diffusion MRI was used to study structural connectivity between prefrontal and striatal regions as critical nodes for action selection. Behavioral findings revealed that increasing age was associated with slowing of action selection performance. At the neural level, aging had a negative impact on prefronto-striatal connectivity. Importantly, mediation analyses revealed that the negative association between action selection performance and age was mediated by prefronto-striatal connectivity, specifically the connections between left rostral medial frontal gyrus and left nucleus accumbens as well as right frontal pole and left caudate. These results highlight the potential role of prefronto-striatal white matter decline in poorer action selection performance of older adults.SIGNIFICANCE STATEMENT As a result of enhanced life expectancy, researchers have devoted increasing attention to the study of age-related alterations in cognitive and motor functions. Here we study associations between brain structure and behavior to reveal the impact of central neural white matter changes as a function of normal aging on action selection performance. We demonstrate the critical role of a reduction in prefronto-striatal structural connectivity in accounting for action selection performance deficits in healthy older adults. Preserving this cortico-subcortical pathway may be critical for behavioral flexibility and functional independence in older age.

Exploring facets of the mindful personality: Dispositional mindfulness and the Big Five

Existing literature indicates inconsistencies regarding the pattern and strength of associations between mindfulness and the Big Five personality traits, potentially due to methodological differences across studies. To address this, we simultaneously assessed associations among mindfulness and all personality traits, controlled for demographic characteristics, and utilized multiple measures of mindfulness in an adult life-span sample (N = 594). Mindfulness was consistently negatively associated with neuroticism. There were small to medium positive associations between mindfulness and conscientiousness, agreeableness, openness, and extraversion. Results differed modestly depending on the type of analysis (regression vs. bivariate correlations) and were mostly similar across different mindfulness measures. Major differences did not emerge as a function of demographic characteristics. Our findings advance the literature by addressing methodological limitations to demonstrate the importance of simultaneously assessing personality traits and using multidimensional measures of mindfulness.

COVID-19 worry, mental health indicators, and preparedness for future care needs across the adult lifespan

Objective The COVID-19 pandemic has been a source of worry for many, but older adults have been identified as more vulnerable to serious cases and may therefore feel more concerned about the virus. We assessed whether COVID-19 worry was related to indicators of mental health and preparedness for future care, in an adult lifespan sample. Method An online study (n = 485; age 18–82, M = 49.31, SD = 15.39) included measures of COVID-19 worry, depression, general anxiety, health anxiety, hostile and benevolent ageism, preparedness for future care, and demographic information. Results Age and living alone were positively associated with greater COVID-19 worry, as were health anxiety, general anxiety, benevolent ageism, and preparedness for future care needs via gathering information. A significant interaction indicated that among individuals reporting lower health anxiety, greater preference for gathering information was positively associated with greater COVID-19 worry; however, for individuals having high health anxiety, gathering information about future care was not related to COVID-19 worry, as their COVID-19 worry levels were moderately high. Conclusion Older age was associated with greater COVID-19 worry, perhaps in response to the much publicized greater risk for negative outcomes in this population. In spite of this specific concern, indicators of older adults’ continued mental health emerged. Preparedness for future care is also highlighted, as well as clinical implications.

Greater BOLD Variability is Associated With Poorer Cognitive Function in an Adult Lifespan Sample.

Moment-to-moment fluctuations in brain signal assessed by functional magnetic resonance imaging blood oxygenation level dependent (BOLD) variability is increasingly thought to represent important “signal” rather than measurement-related “noise.” Efforts to characterize BOLD variability in healthy aging have yielded mixed outcomes, demonstrating both age-related increases and decreases in BOLD variability and both detrimental and beneficial associations. Utilizing BOLD mean-squared-successive-differences (MSSD) during a digit n-back working memory (WM) task in a sample of healthy adults (aged 20–94 years; n = 171), we examined effects of aging on whole-brain 1) BOLD variability during task (mean condition MSSD across 0–2–3-4 back conditions), 2) BOLD variability modulation to incrementally increasing WM difficulty (linear slope from 0–2–3-4 back), and 3) the association of age-related differences in variability with in- and out-of-scanner WM performance. Widespread cortical and subcortical regions evidenced increased mean variability with increasing age, with no regions evidencing age-related decrease in variability. Additionally, posterior cingulate/precuneus exhibited increased variability to WM difficulty. Notably, both age-related increases in BOLD variability were associated with significantly poorer WM performance in all but the oldest adults. These findings lend support to the growing corpus suggesting that brain-signal variability is altered in healthy aging; specifically, in this adult lifespan sample, BOLD-variability increased with age and was detrimental to cognitive performance.

Cerebral Arterial Pulsatility and Global White Matter Microstructure Impact Spatial Working Memory in Older Adults With and Without Cardiovascular Risk Factors.

Aging is associated with an increased prevalence of vascular health conditions that are linked to a disruption in the cerebral vasculature and white matter microstructural organization. In people with cardiovascular risk factors, increased cerebral arterial pulsatility is associated with poorer white matter microstructural organization and cognitive functioning. This study examines the relationship among arterial pulsatility, white matter microstructural organization, and cognitive ability in a healthy adult lifespan sample. One hundred and eighty-nine adults were divided into a younger adult (<50 years, n = 97) and older adult (>50 years, n = 92). The latter were further subdivided into two subgroups with (CV+, n = 25) and without (CV−, n = 67) cardiovascular risk factors. Arterial pulsatility was measured using cardiac-gated phase-contrast flow quantification sequence and three indexes of whole-brain white matter microstructural organization [i.e., fractional anisotropy (FA), radial diffusivity (RaD), mean diffusivity (MD)] were derived from diffusion-weighted imaging (DWI). Cognitive ability was assessed using global cognitive functioning (MoCA) and a measure of working memory [sensitivity (d′) from a 2-back task]. Neither the whole group analysis nor the younger adult group showed an association between measures of arterial pulsatility, global white matter microstructural organization, and cognition. In older adults, higher MD and RaD were associated with increased arterial pulsatility and poorer working memory performance. The indirect pathway from arterial pulsatility to working memory performance via both MD and RaD measures was significant in this group. Interestingly, a comparison of CV+ and CV− subgroups showed that this mediating relationship was only evident in older adults with at least one CV risk factor. These findings are consistent with cardiovascular risk factors as underlying arterial, white matter, and cognitive decline in cognitively normal older adults.

Mind-body practices in U.S. adults: Prevalence and correlates

ObjectivesMind-body practices (MBP), such as Yoga or Tai-Chi, have increased in popularity in the past 25 years in the US. These activities may help promote a less sedentary lifestyle and may have positive effects on health. The objective of the present study is to understand the prevalence and trends of MBP in US adults and the factors associated with their use in a population-based adult lifespan sample. MethodsWe used data from three waves of the Midlife in the United States (MIDUS) survey (1995, 2005, and 2015), a population-based longitudinal study of community-dwelling adults. Only data from participants with valid observations across three waves (N = 2262) aged 24–74 years at baseline (M = 46; SD = 11) were used. We examined the prevalence of MBP, longitudinal patterns, and correlates of MBP use over 20 years. ResultsRates of MBP use were relatively stable over time in this sample, with 20%, 17%, and 18% of participants using MBP at wave 1, 2, and 3, respectively. A number of sociodemographic and health variables were independently related to frequency of MBP use over 20 years: Women, participants with higher levels of education, never married participants, and participants who suffered from multiple chronic health conditions were more likely to use MBP. DiscussionOur findings suggest that MBP may provide an opportunity for physical activity for individuals suffering from chronic health conditions. More research is needed to understand whether this, in turn, results in better health outcomes for these individuals.

The association between cognitive reserve and performance-related brain activity during episodic encoding and retrieval across the adult lifespan

Remembering associations between encoded items and their contextual setting is a feature of episodic memory. Although this ability generally deteriorates with age, there is substantial variability in how older individuals perform on episodic memory tasks. A current topic of debate in the cognitive neuroscience of aging literature revolves around whether this variability may stem from genetic and/or environmental factors related to reserve, allowing some individuals to compensate for age-related decline through differential recruitment of brain regions. In this fMRI study spanning a large adult lifespan sample (N = 154), we tested whether higher cognitive reserve was associated with better task-fMRI context memory performance, and functional compensatory activity patterns in the aging brain. We used multivariate Behaviour Partial Least Squares (B-PLS) analysis to examine how age, retrieval accuracy, and a proxy measure of cognitive reserve [i.e., a composite score consisting of years of education (EDU) and crystallized IQ], impacted brain activity during the encoding and retrieval of spatial and temporal contextual details. The results indicated that age-related increases in encoding activity within anterior and lateral frontal, inferior parietal, occipito-temporal and medial temporal cortices, was correlated with better subsequent memory performance; and may be indicative of age-related functional compensation at encoding. Interestingly this compensatory pattern was not correlated with our proxy measure of cognitive reserve but was associated with total brain volume (a measure of brain reserve). However, cognitive reserve was associated with age-invariant and task-general activity in superior temporal, occipital, and left inferior frontal regions. We conclude that the relationship between cognitive reserve, brain reserve and age-related functional compensation is complex, and that EDU and IQ may not fully account for individual differences in cognitive reserve when studying well educated, healthy aging cohorts.

Same old, same old? Age differences in the diversity of daily life.

Some research suggests that compared with younger adults, older adults have more homogeneous, less diverse daily life experiences because everyday situations and activities become increasingly stable and routine. However, strong empirical tests of this assumption are scarce. In two complementary studies, we examined whether older age is associated with less diversity in daily life experiences (e.g., regarding social interaction partners, activities, and places across and within days) and, if so, to what extent health limitations account for these age differences. In Study 1, we used daily diaries to investigate diversity across days among younger (N = 246; Mage = 21.8 years, SD = 2.5) and older adults (N = 119; Mage = 67.7 years, SD = 5.3). In Study 2, we investigated diversity within days employing experience sampling methods over three weeks in an adult life span sample (N = 365; range = 14-88 years). Results showed that across and within days, the daily lives of older adults were less diverse regarding their social interaction partners. Yet, older adults reported more diversity in activities within days and across days in the afternoons, whereas younger adults reported less diverse activities partly due to working or studying more often. Age differences remained statistically significant when controlling for health limitations. We conclude that age differences in the diversity of daily life are nuanced, depending on the domain and the level of analysis. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Age differences in reported social networks and well-being.

Social networks can consist of close friends, family members, and neighbors as well as peripheral others. Studies of social networks and associations with well-being have mostly focused on age-restricted samples of older adults or specific geographic areas, thus limiting their generalizability. We analyzed 2 online surveys conducted with RAND's American Life Panel, a national adult life span sample recruited through multiple probability-based approaches. In Survey 1, 496 participants assessed the sizes of their social networks, including the number of close friends, family members, neighbors, and peripheral others. Of those, 287 rated their social satisfaction and well-being on Survey 2. Older participants reported smaller social networks, largely because of reporting fewer peripheral others. Yet older age was associated with better well-being. Although the reported number of close friends was unrelated to age, it was the main driver of well-being across the life span-even after accounting for the number of family members, neighbors, and peripheral others. However, well-being was more strongly related to social satisfaction than to the reported number of close friends-suggesting that it is the perception of relationship quality rather than the perception of relationship quantity that is relevant to reporting better well-being. We discuss implications for social network interventions that aim to promote well-being. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Fiber-specific variations in anterior transcallosal white matter structure contribute to age-related differences in motor performance

Age-related differences in bimanual motor performance have been extensively documented, but their underlying neural mechanisms remain less clear. Studies applying diffusion MRI in the aging population have revealed evidence for age-related white matter variations in the corpus callosum (CC) which are related to bimanual motor performance. However, the diffusion tensor model used in those studies is confounded by partial volume effects in voxels with complex fiber geometries which are present in up to 90% of white matter voxels, including the bilateral projections of the CC. A recently developed whole-brain analysis framework, known as fixel-based analysis (FBA), enables comprehensive statistical analyses of white matter quantitative measures in the presence of such complex fiber geometries. To investigate the contribution of age-related fiber-specific white matter variations to age-related differences in bimanual performance, a cross-sectional lifespan sample of healthy human adults (N ​= ​95; 20–75 years of age) performed a bimanual tracking task. Furthermore, diffusion MRI data were acquired and the FBA metrics associated with fiber density, cross-section, and combined fiber density and cross-section were estimated. Whole-brain FBA revealed significant negative associations between age and fiber density, cross-section, and combined metrics of multiple white matter tracts, including the bilateral projections of the CC, indicative of white matter micro- and macrostructural degradation with age. More importantly, mediation analyses demonstrated that age-related variations in the combined (fiber density and cross-section) metric of the genu, but not splenium, of the CC contributed to the observed age-related differences in bimanual coordination performance. These findings highlight the contribution of variations in interhemispheric communication between prefrontal (non-motor) cortices to age-related differences in motor performance.

Decreased inter-hemispheric interactions but increased intra-hemispheric integration during typical aging.

Normal aging is known to be accompanied by decreased segregation across the whole-brain functional network, which is associated with cognitive decline. Although compelling evidence supports reduced segregation and increased integration in whole-brain functional connectivity with aging, the age effect on the reorganization of large-scale functional networks at the hemispheric level remains unclear. Here, we aimed to examine age-related differences in inter-hemispheric interactions and intra-hemispheric integration by using resting-state functional MRI data of a healthy adult lifespan sample. The results showed that age-related decreases in inter-hemispheric integration were found in entire functional networks in both hemispheres, except for the sensorimotor network (SMN) and posterior default mode network (DMN). Specifically, aging was accompanied by increasing inter-hemispheric segregation in the left frontoparietal network (FPN) and left ventral attention network (VAN), as well as right-brain networks located in the auditory network (AN), visual network (VN), and temporal parts of the DMN. Moreover, aging was associated with increasing intra-hemispheric integration within the bilateral VN and posterior DMN while decreasing intra-hemispheric integration within the right VAN. These remarkable changes with aging confirm that there are dynamic interactions between functional networks across the lifespan and provide a means of investigating the mechanisms of cognitive aging.

Age similarities and differences in spontaneous use of emotion regulation tactics across five laboratory tasks.

Theories of emotional aging have proposed that age differences in emotion regulation may partly explain why older adults report high levels of emotional well-being despite declines in other domains. The current research examined age differences and similarities in emotion regulatory tactic preferences across 5 laboratory tasks designed to measure the strategies within the process model of emotion regulation (situation selection, situation modification, attentional deployment, cognitive change, and response modulation). An adult life span sample (ages 20-78, N = 225) completed tasks offering opportunities to use tactics that decrease negative, increase positive, or engage with negative aspects of the situation. Overall, age similarity in tactic preferences (supported by Bayes factors) was much more common than age differences. Across the sample, participants favored avoiding negative aspects in situation selection and modification and seeking or introducing positive aspects in attentional deployment and cognitive change. Self-reports of affect suggest that older adults were more responsive to positive aspects of the situation, although they did not seek them out more than other age groups. These results cast some doubt on the assumption that spontaneous emotion regulation is more likely in older age, but rather show that both younger and older adults show similar preferences in the absence of other strong goals. This novel approach of examining strategies across the process model highlights benefits of comparing multiple tactics within strategies not only when examining possible age differences, but also when studying patterns of emotion regulation in general. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Bottom-up or top-down? Examining global and domain-specific evaluations of how one's life is unfolding over time.

We employed bottom-up and top-down perspectives to evaluate the link between how individuals view their lives as unfolding over time overall and in multiple life domains. Participants from an American adult lifespan sample (n=1,003, mean age=54.39years, 49% female, 94% Caucasian) evaluated their recollected past, current, and anticipated future satisfaction in seven life domains (health, work, finances, contribution to others, relationships with one's children, close relationships, sex life) and for their lives overall (life satisfaction) at two time points separated by 9 years. Mean-level trends varied by life domain and age. In cross-sectional and longitudinal analyses, domain-specific beliefs about changes in one's life explained substantial amounts of variance in perceived changes in overall life satisfaction, and multiple domains had unique predictive effects. Domain-specific beliefs also substantially mediated the predictive effect of age on perceived change in life satisfaction. Findings provide consistent support for the bottom-up perspective and limited support for the top-down model. Accordingly, individuals seem to derive beliefs concerning how their lives overall are unfolding over time based on perceived changes across multiple life domains.

Exploring the contribution of executive functions to on-road driving performance during aging: A latent variable analysis

With the aging of the population the issue of older drivers safety has gained importance in recent years. Age-related cognitive decline is frequently cited as the main cause of unsafe driving performance in older drivers. Objective: The present study investigated how executive functions (EFs), measured as latent variables, are related to on-road driving performance during aging. Method: One hundred and twenty-six participants aged from twenty to eighty-two, completed a two hundred and forty-seven km on-road driving test and a set of executive tasks selected to tap three often postulated EFs: inhibition (inhibiting prepotent responses), updating (updating working memory representations), and shifting (shifting task sets). Results: Confirmatory factor analysis reproduces previous results obtained by Miyake et al. (2000), Miyake and Friedman (2012) of unity and diversity of EFs in an adult life span sample. Structural equation modeling suggested that on-road driving performance was related to inhibition. Furthermore, findings indicate that the age-related driving performance decline in normal aging may be mediated by the inhibition function. Conclusions: The results highlight the importance of a proper method to assess executive functioning in a specific domain as well as emphasising the major role of those functions in driving performance while aging.

Age-related differences in prefrontal-hippocampal connectivity are associated with reduced spatial context memory.

Altered functional connectivity between dorsolateral prefrontal cortex (DLPFC), posterior hippocampus (HC) and other brain regions with advanced age may contribute to age-related differences in episodic memory. In the current fMRI study of spatial context memory, we used seed connectivity analysis to test for age-related differences in the correlations between activity in DLPFC and HC seeds, and the rest of the brain, in an adult life span sample. In young adults, we found that connectivity between right DLPFC and other prefrontal cortex regions, parietal cortex, precuneus, and ventral visual cortices during encoding was positively related to performance. Positive seed connectivity among these regions, and negative connectivity with posterior HC at retrieval was also positively correlated with retrieval accuracy in young adults. In older adults, activity in right DLPFC was positively correlated with activity in this same set of brain regions, and with posterior HC during encoding and retrieval. Interestingly, this pattern of seed connectivity in older adults was negatively correlated with retrieval accuracy. Thus, age-related differences in context memory may be related to altered frontal-parietal and visual cortical interactions with posterior HC. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Genetic predisposition for inflammation exacerbates effects of striatal iron content on cognitive switching ability in healthy aging

Non-heme iron homeostasis interacts with inflammation bidirectionally, and both contribute to age-related decline in brain structure and function via oxidative stress. Thus, individuals with genetic predisposition for inflammation may be at greater risk for brain iron accumulation during aging and more vulnerable to cognitive decline. We examine this hypothesis in a lifespan sample of healthy adults (N = 183, age 20–94 years) who underwent R2*-weighted magnetic resonance imaging to estimate regional iron content and genotyping of interleukin-1beta (IL-1β), a pro-inflammatory cytokine for which the T allelle of the single nucleotide polymorphism increases risk for chronic neuroinflammation. Older age was associated with greater striatal iron content that in turn accounted for poorer cognitive switching performance. Heterozygote IL-1β T-carriers demonstrated poorer switching performance in relation to striatal iron content as compared to IL-1β C/C counterparts, despite the two groups being of similar age. With increasing genetic inflammation risk, homozygote IL-1β T/T carriers had lesser age-related variance in striatal iron content as compared to the other groups but showed a similar association of greater striatal iron content predicting poorer cognitive switching. Non-heme iron and inflammation, although necessary for normal neuronal function, both promote oxidative stress that when accumulated in excess, drives a complex mechanism of neural and cognitive decline in aging.