Objective and Subjective Aging Markers Selectively Predict Different Successful Aging Outcomes

Investigating a community-dwelling cohort from the LIFE-Adult Study in Leipzig, Germany, an interdisciplinary team led by Fabio Selovin and colleagues observed that objective markers of aging—specifically systemic inflammation and executive cognitive function—related selectively to functional indicators such as instrumental activities of daily living and health-related quality of life. In stark contrast, subjective markers of aging—encompassing an individual’s subjective felt age and their personal self-perceptions of aging—associated significantly with life satisfaction and health-related quality of life, yet showed no meaningful statistical association with daily functional self-maintenance. These findings provide clear empirical evidence that fundamental biological resources and psychological evaluations do not act as uniform predictors of late-life well-being, but instead selectively influence discrete, independent facets of what it means to age successfully.

The study was designed to directly address a longstanding fragmentation in gerontological research, where biological markers and psychological constructs have historically been investigated in isolation from one another. While prior inquiries into objective markers of aging have predominantly centered on physiological deterioration, cognitive decline, inflammatory processes, and immune function to forecast whether an individual experiences favorable aging trajectories, psychological research has separately established that subjective age beliefs and aging self-perceptions strongly predict developmental pathways in older adulthood. However, because aging represents an inherently complex, multidimensional phenomenon, the failure to evaluate both objective biological parameters and subjective psychological markers concurrently has created notable gaps in understanding. Without joint modeling, the distinct, relative contributions of biological capacity versus personal appraisal toward specific operational indicators of successful aging—ranging from physical self-sufficiency to subjective life evaluation—remained unresolved across empirical literature.

To rigorously examine these concurrent relationships, the investigators drew cross-sectional data from the large-scale LIFE-Adult Study conducted in Leipzig, Germany. In the baseline assessment spanning between 2011 and 2014, a total of 10,000 individuals between 18 and 86 years of age were randomly chosen from the local population registry via an age- and sex-stratified sampling protocol and completed an extensive assessment protocol. Approximately six years later, between 2017 and 2021, baseline participants were invited to participate in a follow-up assessment, during which 6,115 individuals returned paper-based, self-administered questionnaires. From this respondent pool, a subsample of 1,799 participants attended a comprehensive two- to three-day examination program involving biological and physical profiling at the study center. Because inflammatory cytokine determinations were available for 844 of these individuals, and given the study’s precise substantive focus on late-life successful aging, the researchers restricted their analytical sample exclusively to adults aged 60 years or older to prevent capturing physiological trends not specific to older age. The resulting final analytical sample with complete records across all investigated variables comprised 464 community-dwelling older adults with a mean age of 74 years, a standard deviation of 6 years, and an age range spanning from 60 to 86 years, of whom 48 percent were female.

The operationalization of objective markers of aging incorporated laboratory-based assays of systemic inflammation and immune status, as well as validated neuropsychological testing. High-sensitivity C-reactive protein, measured in milligrams per liter with an analytical detection limit of 0.15 milligrams per liter, and interleukin-6, quantified in picograms per milliliter with an assay threshold of 1.5 picograms per milliliter, were both log-transformed to achieve normal distributions and converted into standardized scores that were averaged to generate a composite inflammatory biomarker index. Cellular immune aging was operationalized as the neutrophil-to-lymphocyte ratio. Because acute bacterial or viral infections can trigger drastic temporary spikes in circulating cytokine concentrations and white blood cell distributions, both the composite inflammation index and the neutrophil-to-lymphocyte ratio were winsorized at the 95th percentile to capture chronic basal immune functioning rather than acute pathology. Cognitive indicators were captured via the Trail Making Test, where Part A assessed visual search and visuo-motor processing speed and Part B introduced cognitive flexibility and working memory. To isolate a unique metric of executive function, test times on Part B were regressed onto Part A completion times, yielding residual executive deficit scores, with both test metrics subsequently winsorized at the 95th percentile to minimize distortion from severe non-normative sensory or physical impairments.

Subjective markers of aging were captured using structured psychometric evaluations assessing personal age identity and future aging expectations. Subjective age was determined by asking participants to report how old they currently felt in years relative to other people, from which a proportional discrepancy score was computed by subtracting chronological age from felt age and dividing the resulting difference by chronological age, such that positive values reflected an older subjective age identity while negative values indicated feeling younger than one’s calendar years; extreme values exceeding three standard deviations from the mean were winsorized. Self-perceptions of aging were operationalized using a three-item scale with an internal consistency reliability coefficient of alpha equal to 0.86, evaluating self-directed expectations regarding whether participants anticipated frequent future illness, physical and mental fitness difficulties, or severe limitations in daily activities due to health challenges. In addition to these primary markers, the modeling controlled for key demographic and socioeconomic covariates, including chronological age, self-reported gender, monthly net household income categorized across thirteen ranked tiers ranging from below 800 euros to above 3,000 euros, and formal educational attainment categorized across thirteen tiers and transformed into years of education ranging from 10 to 18 years.

The research team evaluated three distinct criteria representing functional, hybrid, and hedonic dimensions of successful aging. Functional independence was measured through the Instrumental Activities of Daily Living Scale, an eight-item clinical screening instrument capturing competence across daily self-maintenance domains including telephone use, shopping, food preparation, housekeeping, laundry, transportation, medication responsibility, and personal financial management, scored from 0 to 8 where higher values indicated complete autonomous capability. Health-related quality of life was captured via the ten-item SF-8 Health Survey, encompassing four physical health items, four mental health items, one overall subjective health item, and one bodily pain item, scored such that higher composite averages reflected superior functional and evaluative well-being with a reliability alpha of 0.90. Hedonic well-being was measured through a validated single-item global life satisfaction indicator asking participants to rate their general life satisfaction on a five-point Likert scale ranging from 1 for very dissatisfied to 5 for very satisfied, a concise metric known to correlate strongly with multi-item domain-specific well-being inventories.

Initial bivariate correlational analyses revealed stark dissociations among the study variables and the outcomes of aging success. Instrumental activities of daily living did not correlate significantly with global life satisfaction, nor did daily functioning exhibit a statistically significant correlation with health-related quality of life; however, life satisfaction and health-related quality of life shared a positive association of r equal to 0.22. Socioeconomic and demographic factors exhibited selective patterns: higher education correlated only with higher health-related quality of life (r = 0.19), higher income correlated with both health-related quality of life (r = 0.19) and life satisfaction (r = 0.11), while advancing age was significantly linked to lower functional autonomy (r = -0.16) and reduced health-related quality of life (r = -0.18), but showed no correlation with life satisfaction (r = -0.07). Conversely, subjective markers correlated significantly with health-related quality of life (r = -0.16 for subjective age and r = 0.32 for self-perceptions of aging) and life satisfaction (r = -0.13 for subjective age and r = 0.23 for self-perceptions of aging), but demonstrated no significant relationship with daily functional self-maintenance.

These selective associations were formally confirmed through hierarchical ordinary least squares multiple linear regression models that tested incremental variance explained across three successive steps: a baseline covariate model, an objective marker model, and a final model incorporating subjective markers alongside all preceding variables with all predictors grand-mean centered. In predicting instrumental activities of daily living, the addition of objective markers did not yield a statistically significant overall increase in explained variance (F(4) = 1.77, p = 0.13), although higher residual executive cognitive deficits emerged as an individual significant predictor of lower functional autonomy (B = -0.001, p < 0.05); entering subjective markers in the third step provided negligible change (F(2) = 0.16, p = 0.84) with neither psychological variable reaching significance. In predicting health-related quality of life, adding objective markers produced a significant increase in explained variance (F(4) = 3.74, p < 0.05), driven by elevated systemic inflammation predicting lower quality of life; adding subjective markers yielded a further substantial increase in explained variance (F(2) = 24.89, p < 0.001), wherein positive self-perceptions of aging strongly predicted higher quality of life (B = 0.11, p < 0.001), male gender remained significant (B = -0.17, p < 0.05), younger age was significant (B = -0.02, p < 0.05), and systemic inflammation retained a marginally significant negative association (B = -0.07, p = 0.05). Finally, in predicting life satisfaction, objective markers explained no additional variance over baseline covariates (F(4) = 0.64, p = 0.63), whereas adding subjective markers produced a highly significant increase in explanatory power (F(2) = 11.80, p < 0.001), with both feeling subjectively younger (B = -1.00, p < 0.05) and endorsing positive self-perceptions of aging (B = 0.08, p < 0.001) significantly predicting superior life satisfaction.

In evaluating these observed empirical patterns, the authors highlighted that the complete lack of association between biological or cognitive markers and evaluative life satisfaction replicates an established body of gerontological literature demonstrating that distal hedonic well-being is often buffered against biological deterioration. The authors offered the speculative hypothesis that psychological adaptation, accommodative adjustments in personal evaluative standards, and cognitive reappraisal processes may shield overall life satisfaction from declining physical capacity; however, because these specific adaptive processes were not directly measured in the study, this explanation remains a theoretical conjecture requiring future testing. In contrast, health-related quality of life functions as a hybrid construct uniting objective somatic symptoms with personal evaluations of health status. Meanwhile, the specific association between residual executive dysfunction and reduced instrumental activities of daily living underscores that higher-order cognitive flexibility and working memory are paramount for complex everyday routines such as managing medication regimens, handling finances, and shopping, where cognitive slips carry immediate, high-stakes consequences.

Several methodological boundaries and contextual limitations must be considered when interpreting these findings. Foremost, the study utilized a cross-sectional analytical design, capturing a static snapshot of associations at a single time point rather than tracing longitudinal trajectories or establishing causal relationships between biological decline, psychological perception, and aging outcomes. Furthermore, the analysis did not account for the confounding influence of over-the-counter or prescribed medications, such as non-steroidal anti-inflammatory drugs including ibuprofen, diclofenac, or aspirin, which directly modulate circulating cytokine concentrations and alleviate bodily pain, potentially dampening the observed magnitude of biological aging effects. Additionally, because the sample comprised healthy, non-institutionalized community-dwelling older adults and the Trail Making Test does not replace clinical screening instruments such as the Mini-Mental State Examination or the Montreal Cognitive Assessment, subtle or pathological cognitive impairments could not be fully differentiated, and the Instrumental Activities of Daily Living Scale may have lacked sensitivity to detect nuanced functional variations among high-functioning individuals. Finally, the authors noted that study hypotheses and analytical models were not preregistered, and global life satisfaction was evaluated through a single-item metric, reinforcing that future research must employ longitudinal, multi-domain designs to track how biological and subjective aging markers dynamically interact across late adulthood.

Subject of Research: Differential associations of objective biological markers and subjective aging perceptions with functional and hedonic successful aging outcomes

Article Title: Concurrent associations between objective markers and subjective markers of aging with indicators of successful aging: An integrative approach

Article References: Selovin, F., de Paula Couto, M. C. P., Scholz, M., Baber, R., Riedel-Heller, S. G., Wirkner, K., Zeynalova, S., & Rothermund, K. (2026). Concurrent associations between objective markers and subjective markers of aging with indicators of successful aging: An integrative approach. European Journal of Ageing, 23(1), Article 18. https://doi.org/10.1007/s10433-026-00920-1

Image Credits: AI Generated

DOI: 10.1007/s10433-026-00920-1

Keywords: gerontology, successful aging, systemic inflammation, cognitive functioning, subjective age, life satisfaction, activities of daily living, health-related quality of life, Concurrent, associations, between, objective