Cohort differences in cognitive aging: The role of perceived work environment

New evidence of trends in cognitive function among middle-aged and older adults in China, 2011-2018: an age-period-cohort analysis

BACKGROUND

Increasing evidence from high-income countries suggests the risk of cognitive impairment has been declining recently. However, related studies in China have rarely been done, and the results are inconsistent. We analyze the trends in cognitive function among middle-aged and older adults in China between 2011 and 2018.

METHODS

We used data from four waves of the China Health and Retirement Longitudinal Study (CHARLS), including 48918 individuals aged 45 years and older. Cognitive function was assessed using the CHARLS cognitive measures containing episodic memory, orientation, attention, and visuospatial abilities. The hierarchical age-period-cohort (APC) model was used to quantify the separate age, period, and cohort effects on trends in cognitive function.

RESULTS

The study sample's ages ranged from 45 to 105 years (Mean = 59.2, SD = 9.4). Cognitive function declined with age net of period and cohort effects, an apparent acceleration in the rate of cognitive decline after age 65 was found adjusting for individual characteristics. Although period effects on trends in cognitive function remained stable during the study period, hierarchical APC models demonstrated significant cohort variations. Independent of age and period effects, there was a fluctuating trend across cohorts before 1960 and an overall decline across successive cohorts.

CONCLUSIONS

Our study indicates that the age effect remains the most crucial factor regarding cognitive decline. Moreover, results demonstrate that cohorts living in social upheaval leading to educational deprivation and/or nutritional deficiency in early life may face a higher risk for cognitive deterioration later in life. Such findings indicate that dementia prevention from a life course perspective and cohort-specific strategies are critical to alleviating the future public-health burdens related to cognitive aging. Ongoing attention should be paid to the role of cross-cohort differences in education on cohort trends in cognition in countries like China that are aging rapidly and have a late start in educational expansion compared to other countries. Other factors, such as environmental stimulation, need to be noticed in younger cohorts.

The Influence of Birth Cohorts on Future Cognitive Decline

BACKGROUND

Slowed rates of cognitive decline have been reported in individuals with higher cognitive reserve (CR), but interindividual discrepancies remain unexplained. Few studies have reported a birth cohort effect, favoring later-born individuals, but these studies remain scarce.

OBJECTIVE

We aimed to predict cognitive decline in older adults using birth cohorts and CR.

METHODS

Within the Alzheimer's Disease Neuroimaging Initiative, 1,041 dementia-free participants were assessed on four cognitive domains (verbal episodic memory; language and semantic memory; attention; executive functions) at each follow-up visit up to 14 years. Four birth cohorts were formed according to the major historical events of the 20th century (1916-1928; 1929-1938; 1939-1945; 1946-1962). CR was operationalized by merging education, complexity of occupation, and verbal IQ. We used linear mixed-effect models to evaluate the effects of CR and birth cohorts on rate of performance change over time. Age at baseline, baseline structural brain health (total brain and total white matter hyperintensities volumes), and baseline vascular risk factors burden were used as covariates.

RESULTS

CR was only associated with slower decline in verbal episodic memory. However, more recent birth cohorts predicted slower annual cognitive decline in all domains, except for executive functions. This effect increased as the birth cohort became more recent.

CONCLUSION

We found that both CR and birth cohorts influence future cognitive decline, which has strong public policy implications.

Attention Performance Decline After Age 40 in Clinically Normal Community Dwellers: Evidence from a 10-Year Follow-Up of the Yakumo Study

Age-related changes in attention ability and differences by gender in the rates of change from middle age were investigated. Digit Cancellation Test (D-CAT1 and D-CAT3 conditions, which involve low and high cognitive load, respectively) scores and individually calculated decline rates (DRs) in 10-year follow-up among four age groups (40s, 50s, 60s, and 70s) were examined. Performance in both D-CAT conditions declined with increasing age from the 50s to the 70s, whereas there was no difference between the 40s and 50s, and a gender difference (with the women showing an advantage) was demonstrated in the 40s and 50s groups on the D-CAT3. In the D-CAT1 condition, the DR remained stable from the 40s to the 50s but increased from the 50s and to the 60s and then remained the same. In the D-CAT3 condition, the DR became larger even after the 70s. The DRs did not differ between men and women from middle age onward. Although DRs showed no gender difference, D-CAT performance showed a gender difference, with men being about 20% less capable by the age of 40. We suggest that data showing concrete declines in attentional performance after middle age may be used to reduce accidents encountered in the daily life of older adults.

Chinese Color Nest Project : An accelerated longitudinal brain-mind cohort

The ongoing Chinese Color Nest Project (CCNP) was established to create normative charts for brain structure and function across the human lifespan, and link age-related changes in brain imaging measures to psychological assessments of behavior, cognition, and emotion using an accelerated longitudinal design. In the initial stage, CCNP aims to recruit 1520 healthy individuals (6-90 years), which comprises three phases: developing (devCCNP: 6-18 years, N = 480), maturing (matCCNP: 20-60 years, N = 560) and aging (ageCCNP: 60-84 years, N = 480). In this paper, we present an overview of the devCCNP, including study design, participants, data collection and preliminary findings. The devCCNP has acquired data with three repeated measurements from 2013 to 2017 in Southwest University, Chongqing, China (CCNP-SWU, N = 201). It has been accumulating baseline data since July 2018 and the second wave data since September 2020 in Chinese Academy of Sciences, Beijing, China (CCNP-CAS, N = 168). Each participant in devCCNP was followed up for 2.5 years at 1.25-year intervals. The devCCNP obtained longitudinal neuroimaging, biophysical, social, behavioral and cognitive data via MRI, parent- and self-reported questionnaires, behavioral assessments, and computer tasks. Additionally, data were collected on children's learning, daily life and emotional states during the COVID-19 pandemic in 2020. We address data harmonization across the two sites and demonstrated its promise of characterizing the growth curves for the overall brain morphometry using multi-center longitudinal data. CCNP data will be shared via the National Science Data Bank and requests for further information on collaboration and data sharing are encouraged.

Birth Cohorts and Cognitive Reserve Influence Cognitive Performances in Older Adults

BACKGROUND

Evidence suggests birth cohort differences in cognitive performance of older adults. Proxies of cognitive reserve (CR), such as educational attainment and occupational complexity, could also partly account for these differences as they are influenced by the sociocultural environment of the birth cohorts.

OBJECTIVE

To predict cognitive performance using birth cohorts and CR and examine the moderating influence of CR on cognitive performance and structural brain health association.

METHODS

Using ADNI data (n = 1628), four birth cohorts were defined (1915-1928; 1929-1938; 1939-1945; 1946-1964). CR proxies were education, occupational complexity, and verbal IQ. We predicted baseline cognitive performances (verbal episodic memory; language and semantic memory; attention capacities; executive functions) using multiple linear regressions with CR, birth cohorts, age, structural brain health (total brain volume; total white matter hyperintensities volume) and vascular risk factors burden as predictors. Sex and CR interactions were also explored.

RESULTS

Recent birth cohorts, higher CR, and healthier brain structures predicted better performance in verbal episodic memory, language and semantic memory, and attention capacities, with large effect sizes. Better performance in executive functions was predicted by a higher CR and a larger total brain volume, with a small effect size. With equal score of CR, women outperformed men in verbal episodic memory and language and semantic memory in all cohorts. Higher level of CR predicted better performance in verbal episodic memory, only when total brain volume was lower.

CONCLUSION

Cohort differences in cognitive performance favor more recent birth cohorts and suggests that this association may be partly explained by proxies of CR.

Role-Based Framing of Older Adults Linked to Decreased Ageism Over 210 Years: Evidence From a 600-Million-Word Historical Corpus

BACKGROUND AND OBJECTIVES

Older adults are exhibiting greater diversity in their aging trajectories. This has led to movements by the World Health Organization and AARP to reframe aging. We compare role-based framing and age-based framing of older adults over 210 years-a time span beyond the reach of traditional methods-and elucidate their respective sentiments and narratives.

RESEARCH DESIGN AND METHODS

We combined the Corpus of Historical American English with the Corpus of Contemporary American English to create a 600-million-word-dataset-the largest historical corpus of American English with over 150,000 texts collected from newspapers, magazines, fiction and non-fiction. We compiled the top descriptors of age-based terms (e.g., senior citizen) and role-based terms (e.g., grandparent) and rated them for stereotypic valence (negative to positive) over 21 decades.

RESULTS

Age-based framing evidenced a significantly higher increase in negativity (15%) compared to role-based framing (4%). We found a significant interaction effect between framing (age-based vs. role-based) and stereotypic content across two centuries (1800s and 1900s). The percentage of positive topics associated with role-based framing increased from 71% in the 1800s to 89% in the 1900s, with narratives of affection and wisdom becoming more prevalent. Conversely, the percentage of positive topics for age-based framing decreased from 82% to 38% over time, with narratives of burden, illness and death growing more prevalent.

DISCUSSION AND IMPLICATIONS

We argue for a more role-centric approach when framing aging such that age ceases to be the chief determinant in how older adults are viewed in society.

Risk of cognitive declines with retirement: Who declines and why?

Retiring is associated with increased risk of cognitive decline (e.g., Bonsang, Adam, & Perelman, 2012; Wickrama, O'Neal, Kwag, & Lee, 2013). However, little is known about the moderating role of motivational and demographic factors that are implicated in adaptive development and the retirement transition process. We used data from the Midlife in the United States Study (n = 732, Mage = 57, SD = 5.76, 50% female) to examine whether the association between retirement and cognitive decline depended on a key motivation factor (goal disengagement) in propensity score matched samples of older retirees and employees. We explored whether these effects were further moderated by gender. Results showed that those who retired (vs. remained employed) experienced steeper 9-year declines in episodic memory (b = -.41, p = .001) only if they were high in goal disengagement and female. Findings are consistent with theories of lifespan development and cognitive aging and provide initial evidence that retirement may be associated with increased cognitive declines for only certain individuals prone to disengage from highly challenging activities and goal pursuits. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Midlife in the 2020s: Opportunities and challenges

Development is a cumulative, lifelong process, but strikingly little is known about development in midlife. As a consequence, many misconceptions exist about the nature of midlife and the developmental milestones and challenges faced by middle-aged adults. We first review dominant views and empirical research that has debunked false narratives. Next, we discuss major opportunities and challenges of midlife. This includes the unique constellation of roles and life transitions that are distinct from earlier and later life phases as well as shifting trends in mental and physical health and in family composition. We additionally highlight the importance of (historical shifts in) intergenerational dynamics of middle-aged adults with their aging parents, adult children, and grandchildren; financial vulnerabilities that emerge and often accrue from economic failures and labor market volatility; the shrinking social and health care safety net; and the rising costs of raising children. In doing so, we discuss issues of diversity and note similarities and differences in midlife experiences across race or ethnicity, sexual orientation, and socioeconomic status. We consider midlife as a pivotal period that includes a focus on balancing gains and losses, linking earlier and later life periods, and bridging generations. Finally, we propose possibilities for promoting reversibility and resilience with interventions and policy changes. The suggested agenda for future research promises to reconceptualize midlife as a key period of life, with a concerted effort to focus on the diversity of midlife experiences in order to meet the unprecedented challenges and opportunities in the 2020s and beyond. (PsycInfo Database Record (c) 2020 APA, all rights reserved).