Depression Mediates the Association Between Occupational Complexity and Late-Life Cognition in Hispanics

There is a dearth of research in Latin America regarding risk and protective factors affecting older adults’ cognition. This study aimed to investigate the factors mediating the association between occupational complexity and late-life cognition and daily function in a sample of Hispanic older adults. Participants (n = 588) aged 65 years and older underwent clinical, functional, and cognitive assessments. Mediation analyses revealed that depressive symptoms mediated the relationship between occupational complexity and cognitive as well as functional outcomes. Results provide evidence that depression may act as a risk factor for worse outcomes, even if older adults had a cognitively demanding occupation.

Workplace Demands and Cognitive Health Inequities Across Race and Ethnicity: A Scoping Review

This PRISMA informed scoping review sought to understand the longitudinal association between workplace demands with cognitive health; and to review how race and ethnicity are investigated in this area of research and evidence of moderating effects. Peer-reviewed articles were drawn from five databases. Inclusion criteria were populations aged 18+, broad conceptualization of workplace demands (e.g., occupational complexity, mental work demands), and cognitive health outcomes (e.g., cognitive functioning, ADRD). The majority of studies drew from theories that did not interrogate heterogeneity and diverse aging experiences. Consequently, the majority of studies (85%) did not investigate inequities by race and ethnicity although variables and methods are available. Cognitive health inequities are evidenced but findings are mixed and more rigorous causal research is needed. We discuss integrating emerging critical theories (e.g. Critical Race Theory, critical gerontology, minority stress) to sharpen the focus on racial health inequities in an emerging area of prevention research.

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.

Education, Occupational Complexity, and Incident Dementia: A COSMIC Collaborative Cohort Study

Background: Education and occupational complexity are main sources of mental engagement during early life and adulthood respectively, but research findings are not conclusive regarding protective effects of these factors against late-life dementia. Objective: This project aimed to examine the unique contributions of education and occupational complexity to incident dementia, and to assess the mediating effects of occupational complexity on the association between education and dementia across diverse cohorts. Method: We used data from 10,195 participants (median baseline age = 74.1, range = 58∼103), representing 9 international datasets from 6 countries over 4 continents. Using a coordinated analysis approach, the accelerated failure time model was applied to each dataset, followed by meta-analysis. In addition, causal mediation analyses were performed. Result: The meta-analytic results indicated that both education and occupational complexity were independently associated with increased dementia-free survival time, with 28%of the effect of education mediated by occupational complexity. There was evidence of threshold effects for education, with increased dementia-free survival time associated with ‘high school completion’ or ‘above high school’ compared to ‘middle school completion or below’. Conclusion: Using datasets from a wide range of geographical regions, we found that both early life education and adulthood occupational complexity were independently predictive of dementia. Education and occupational experiences occur during early life and adulthood respectively, and dementia prevention efforts could thus be made at different stages of the life course.

Exploring the association between occupational complexity and numeracy

The basic cognitive skill of numeracy is a recognized form of human capital, associated with economic and social well being for individuals and for nations. In this study, we explore how occupational complexity relates to proficiency in numeracy, among adults in full-time employment. We operationalize occupational complexity by constructing three measures of task complexity: complexity with data, complexity with people and complexity with things. Data from the international OECD survey of adult skills, 2012, is employed to investigate both the distribution of these three dimensions of occupational task complexity and how these relate to numeracy in 13 countries. The analysis indicates that data occupational complexity predicts numeracy scores, when controlling for age, gender and educational level. The findings open for a hypothesis that occupational activities may enhance basic skills in adult populations. If elaborated and supported through further studies this finding has practical implications for workplace organization and contributes to theoretical understandings of the development of basic skills in adults.

Verbal intelligence is a more robust cross-sectional measure of cognitive reserve than level of education in healthy older adults

BackgroundCognitive reserve is most commonly measured using socio-behavioural proxy variables. These variables are easy to collect, have a straightforward interpretation, and are widely associated with reduced risk of dementia and cognitive decline in epidemiological studies. However, the specific proxies vary across studies and have rarely been assessed in complete models of cognitive reserve (i.e., alongside both a measure of cognitive outcome and a measure of brain structure). Complete models can test independent associations between proxies and cognitive function in addition to the moderation effect of proxies on the brain-cognition relationship. Consequently, there is insufficient empirical evidence guiding the choice of proxy measures of cognitive reserve and poor comparability across studies.MethodIn a cross-sectional study, we assessed the validity of 5 common proxies (education, occupational complexity, verbal intelligence, leisure activities, and exercise) and all possible combinations of these proxies in 2 separate community-dwelling older adult cohorts: The Irish Longitudinal Study on Ageing (TILDA; N = 313, mean age = 68.9 years, range = 54–88) and the Cognitive Reserve/Reference Ability Neural Network Study (CR/RANN; N = 234, mean age = 64.49 years, range = 50–80). 15 models were created with 3 brain structure variables (grey matter volume, hippocampal volume, and mean cortical thickness) and 5 cognitive variables (verbal fluency, processing speed, executive function, episodic memory, and global cognition).ResultsNo moderation effects were observed. There were robust positive associations with cognitive function, independent of brain structure, for 2 individual proxies (verbal intelligence and education), and 16 composites (i.e., combinations of proxies). Verbal intelligence was statistically significant in all models. Education was significant only in models with executive function as the cognitive outcome variable. Three robust composites were observed in more than two thirds of brain-cognition models: the composites of 1) occupational complexity and verbal intelligence, 2) education and verbal intelligence, and 3) education, occupational complexity and verbal intelligence. However, no composite had larger average effects nor was more robust than verbal intelligence alone.ConclusionThese results support the use of verbal intelligence as a proxy measure of CR in cross-sectional studies of cognitively healthy older adults.

Verbal intelligence is a more robust cross-sectional measure of cognitive reserve than level of education in healthy older adults

Background Cognitive reserve is most commonly measured using socio-behavioural proxy variables. These variables are easy to collect, have a straightforward interpretation, and are widely associated with reduced risk of dementia and cognitive decline in epidemiological studies. However, the specific proxies vary across studies and have rarely been assessed in complete models of cognitive reserve (i.e. alongside both a measure of cognitive outcome and a measure of brain structure). Complete models can test independent associations between proxies and cognitive function in addition to the moderation effect of proxies on the brain-cognition relationship. Consequently, there is insufficient empirical evidence guiding the choice of proxy measures of cognitive reserve and poor comparability across studies. Method In a cross-sectional study, we assessed the validity of 5 common proxies (education, occupational complexity, verbal intelligence, leisure activities, and exercise) and all possible combinations of these proxies in 2 separate community-dwelling older adult cohorts: The Irish Longitudinal Study on Ageing (TILDA; N = 313, mean age = 68.9 years, range = 54–88) and the Cognitive Reserve/Reference Ability Neural Network Study (CR/RANN; N = 234, mean age = 64.49 years, range = 50–80). Fifteen models were created with 3 brain structure variables (grey matter volume, hippocampal volume, and mean cortical thickness) and 5 cognitive variables (verbal fluency, processing speed, executive function, episodic memory, and global cognition). Results No moderation effects were observed. There were robust positive associations with cognitive function, independent of brain structure, for 2 individual proxies (verbal intelligence and education) and 16 composites (i.e. combinations of proxies). Verbal intelligence was statistically significant in all models. Education was significant only in models with executive function as the cognitive outcome variable. Three robust composites were observed in more than two-thirds of brain-cognition models: the composites of (1) occupational complexity and verbal intelligence, (2) education and verbal intelligence, and (3) education, occupational complexity, and verbal intelligence. However, no composite had larger average effects nor was more robust than verbal intelligence alone. Conclusion These results support the use of verbal intelligence as a proxy measure of CR in cross-sectional studies of cognitively healthy older adults.

How long are newcomers new in different occupations?

Purpose This study aims to examine the effects of occupational characteristics on the length of time required to socialize newcomers. The authors examine task mastery, role clarity and social acceptance as indicators of socialization. Design/methodology/approach To test the hypotheses, the authors used occupational data from the Bureau of Labor Statistics and survey data of subject matter experts in 35 occupations. Findings Findings show that occupational differences account for a significant variance in the time needed to socialize newcomers. Across occupations, it takes longer to achieve task mastery than role clarity or social acceptance. Occupational complexity increases the time it takes for newcomers to attain task mastery, role clarity and social acceptance. Additionally, unstructured work and decision-making freedom increase the time it takes for newcomers to attain role clarity. Originality/value This study provides both theoretical and empirical guidance on the duration of the organizational socialization period. The study also provides empirical support for prior propositions that different types of newcomer learning occur at different rates.

Protective Effect of Occupational Complexity on Working Memory in Patients with Frontal Lobe Tumors

Cognitive reserve (CR) is the capacity to cope with cognitive impairments due to brain damage by neurological disease. CR is increased by intellectually enriching activities, such as education, occupation, and leisure. After brain tumor resection, patients show working memory impairment because of damage to fronto-parietal networks, such as the superior longitudinal fascicle (SLF). To date, whether occupational experience represented as CR impacts postoperative working memory impairment in patients with frontal lobe tumors remains unknown. We hypothesized that occupational experience predicted postoperative working memory and that higher damage in the SLF was associated with poorer working memory. We enrolled 27 patients who had undergone tumor resection. Patient's occupational experience was estimated using an occupational complexity index based on a dictionary of occupational titles. Working memory was measured using verbal and spatial working memory tasks. Our results showed that patients who had engaged in more complex occupations showed higher performance of postoperative working memory, which supported the previous CR hypothesis. In conclusion, CR has protective effects against working memory impairment in patients with frontal lobe tumors. CR measures, such as occupational experience, will help more accurately predict the severity of working memory deficits and the likelihood of recovery in the postoperative period.