Brea Louise Perry

Objectives: Prior research often reports geographic cognitive health disparities in later life, including across rural–urban contexts. Yet few studies have examined the role of personal social networks in shaping these geographic disparities. This study investigates whether social networks moderate or mediate the association between geographic context and cognitive health. Methods: We use data from the Social Environment and Cognitive Health in Urban and Rural Areas study, which is a state representative sample of adults aged 55 and older. A latent measure of social bridging (i.e., connections to weak and diverse ties) was extracted using personal network data. Cognitive health was measured using the Montreal Cognitive Assessment (MoCA). Rurality was defined using the Indiana County Classification. Moderation and mediation pathways were tested using linear regression models. Results: There were no observed rural–urban differences in MoCA scores. Yet the association between social bridging and MoCA was significantly stronger among rural participants compared to urban participants. Rural participants with the lowest levels of social bridging performed significantly worse on the MoCA compared to urban participants with similar bridging levels. These geographic disparities were not present when comparing rural and urban participants with high levels of social bridging. Discussion: The ability to personally bridge social ties within a network appears to play a more critical role in the cognitive health of rural residents, who live in communities with fewer structural opportunities for social stimulation, compared to urban residents.

Objectives: The Social Environment and Cognitive Health in Urban and Rural Areas study was designed to examine cognitive health disparities in later life. It gathers data on access to social resources, engagement in cognitively stimulating interactions, and exposure to activity spaces. Methods: We enrolled 510 participants from 41 Indiana counties during baseline data collection in Fall 2023. All participants completed a computer-assisted personal interview survey that collected data on their cognitive, mental, and physical health, personal networks, sociodemographic attributes, occupational history, lifestyle activities, and social support. 273 participants completed a follow-up module in which they used a smartphone to record ecological momentary assessments (EMAs) that were administered 4 times per day for 7 days. Results: The mean age was 69.9 years. Most participants were women (64.5%), White (90.2%), and retired (54.5%). The average participant named 5.38 network members. Participants were at home (70.7%) and alone (60.2%) for the majority of their EMAs. Approximately one third of the sample scored below a recommended cutoff for mild cognitive impairment on the Montreal Cognitive Assessment. Discussion: We conclude by outlining a research agenda that (a) characterizes the social networks, interactions, and place-based activities of participants across geographic contexts, and (b) assesses the potential pathways between a combination of networks, interactions, and activities and cognitive function.

Daily social interactions provide access to key social resources, yet little research has examined how these interactions vary across geographic space—particularly in later life. Using ecological momentary assessment data from a state-representative study of older adults in Indiana, we examine how interactions with different partners vary across a continuum of municipality population density. Further, we assess whether this variation is shaped by social opportunity structures—such as number of community parks, theaters, and volunteer organizations—and whether patterns persist during leisure time, when individuals are free to choose their interaction partners. Results show that higher population density is associated with more time spent alone, more interactions with “shared-foci partners” (i.e., partners known through foci of activity, such as neighbors, professionals, congregation members—though associations are driven primarily by professionals, strangers, and “others”), and fewer interactions with kin. Adjusting for social opportunity structures does not affect the observed association between population density and aloneness, interactions with shared-foci partners, or interactions with kin, indicating that differential access to social opportunity spaces does not explain these relationships. Restricting analyses to leisure activities reveals that differences in shared-foci partner interactions by population density disappear—implying they are driven by variation in obligatory tasks—while differences in kin interactions and, to a lesser extent, time spent alone persist. By identifying population density as a structural factor that shapes everyday sociality, this study underscores the role of geographic context in structuring older adults’ access to social connection and the resources embedded in daily interaction.

Reply to Zhang: Causal identification, social networks, and biological aging

Objectives: Cognitive reserve (CR) refers to the ability to sustain cognitive performance despite age- and disease-related brain changes, which supports prolonged independent living. Prior research suggests that education, occupational complexity, participation in cognitively engaging and social activities, lifestyle factors, and social connectedness may enhance CR. However, few studies directly compare the relative significance of these factors within the same sample, using magnetic resonance imaging (MRI) based brain markers to measure CR. We also examine whether, and to what extent, relatively proximal factors serve as downstream effects of education within a cumulative (dis)advantage framework. Methods: We analyzed data from 279 MRI visits from 201 older adults enrolled in the Social Networks and Alzheimer’s Disease study, diagnosed as cognitively normal or with mild cognitive impairment. CR was assessed as residual global cognition based on MRI-derived brain measures and demographic covariates. Multivariate models estimated standardized effect sizes for each factor, followed by mediation analyses to assess whether they are downstream of education. Results: As expected, higher educational attainment was significantly associated with greater CR. Among occupational measures, only complexity with people showed a significant relationship, but this association diminished in fully adjusted models. Cognitive-oriented activities and social network bridging capital were independently associated with CR, while only bridging capital remained significant in fully adjusted models and mediated ∼11% of the association between education and CR. Discussion: While early-life education appears fundamental to CR, broader and more diverse social networks are beneficial, partly reflecting downstream effects of education, and may represent a modifiable pathway to promote CR.

Exposure to psychosocial stress is a well-established risk factor for poor health and premature mortality, yet most research has focused narrowly on single sources of stress without simultaneously modeling multiple stress exposures occurring across the life span. Using data from a state-representative sample of 2,267 adults ages 18–103, we examined associations between four psychosocial stressors – adverse childhood experiences (ACEs), stressful life events, chronic financial strains, and everyday discrimination – and DNA methylation-based biological aging clocks (GrimAge2 and DunedinPACE) alongside six indicators of physical and mental health outcomes. All stressors were associated with accelerated epigenetic aging and poorer health when examined individually. However, when considered simultaneously, financial strains and everyday discrimination emerged as more consistent predictors across all outcomes, relative to childhood adversity and stressful events in adulthood. Overall, stressor effects were more pronounced for mental health compared to physical health or biological aging. These findings highlight the importance of considering multiple sources of stress on varying indicators of aging, disease, and distress to fully account for the health significance of stress exposure.

Negative social ties, or “hasslers,” are pervasive yet understudied components of social networks that may accelerate biological aging and morbidity. Using ego-centric network data and DNA methylation-based biological aging clocks (i.e., DunedinPACE and age-accelerated GrimAge2) from saliva from a state representative probability sample in Indiana, we examine how negative social ties are associated with accelerated biological aging and a broad range of health outcomes, including inflammation and multimorbidity. Negative relationships are not rare within close relationships, as nearly 30% of individuals report having at least one hassler in their network. These hasslers tend to occupy peripheral network positions and are more likely to be connected through weak, uniplex ties. Importantly, exposure to negative social ties follows patterns of social and health vulnerability, with women, daily smokers, people in poorer health, and those with adverse childhood experiences more likely to report having hasslers in their networks. Having more hasslers is associated with accelerated biological aging in both rate and cumulative burden: Each additional hassler corresponds to approximately 1.5% faster pace of aging and roughly 9 mo older biological age. Moreover, not all hasslers exert the same influence; kin and nonkin hasslers show detrimental associations, whereas spouse hasslers do not. Finally, a greater number of hasslers is associated with multiple adverse health outcomes beyond epigenetic aging. These findings together highlight the critical role of negative social ties in biological aging as chronic stressors and the need for interventions that reduce harmful social exposures to promote healthier aging trajectories.

A growing number of social scientists are using ecological momentary assessment (EMA) to observe how social forces operate in real time. However, the validity of EMA for measuring features of daily life—what people are doing, where, and with whom—remains uncertain. A key challenge is the lack of consensus across studies about how validity in EMA methods is defined and assessed. The authors address that gap by comparing EMA data (n = 1,174) with time diary data (n = 1,113) using two population-based samples. An advantage of large samples is the ability to evaluate the magnitude of bias rather than relying solely on p-values, as is common in small-sample studies. The authors find that both methods yield similar estimates of moments captured at home and in the workplace, supporting their validity in those contexts. However, EMA tends to overestimate moments spent alone compared with time diaries, likely because of moment selection bias. Moreover, large discrepancies in estimates for eating and drinking and household chores suggest that relying on primary activity reports can introduce significant bias for multitasked activities. Comparing these methods provides insight into their relative strengths and limitations, helping researchers assess the validity, potential biases, and interpretive implications of each across key domains of daily life.