Cadar et al., 2016. The role of cognitive reserve on terminal decline: a cross-cohort analysis from two European studies

Cadar, D., Stephan, B. C., Jagger, C., Johansson, B., Hofer, S. M., Piccinin, A. M., & Muniz‐Terrera, G. (2016). The role of cognitive reserve on terminal decline: A cross‐cohort analysis from two European studies: OCTO‐Twin, Sweden, and Newcastle 85+, UK. International Journal of Geriatric Psychiatry, 31(6), 601-610.

Year: 
2017
Status: 
complete
Abstract: 

OBJECTIVE: Cognitive performance shows a marked deterioration in close proximity to death, as postulated by the terminal decline hypothesis. The effect of education on the rate of terminal decline in the oldest people (i.e. persons 85+ years) has been controversial and not entirely understood. In the current study, we investigated the rate of decline prior to death with a special focus on the role of education and socioeconomic position, in two European longitudinal studies of ageing: the Origins of Variance in the Old-Old: Octogenarian Twins (OCTO-Twin) and the Newcastle 85+ study.

METHODS: A process-based approach was used in which individuals' cognitive scores were aligned according to distance to death. In a coordinated analysis, multilevel models were employed to examine associations between different markers of cognitive reserve (education and socioeconomic position) and terminal decline using the mini-mental state examination (MMSE), controlling for age at baseline, sex, dementia incidence and time to death from the study entry to the time of death within each cohort.

RESULTS: The current findings suggest that education was positively associated with higher MMSE scores prior to death in the OCTO-Twin, but not in the Newcastle 85+ study, independent of socioeconomic position and other factors such as baseline age, sex and time to death from the study entry. However, education was not associated with the rate of terminal decline in both of these studies.

CONCLUSIONS: Our results offer only partial support to the cognitive reserve hypothesis and cognitive performance prior to death.

Robitaille et al., 2018. Transitions across cognitive states and death among older adults in relation to education: a multi-state survival model using data from six longitudinal studies.

Robitaille, A., van den Hout, A., Machado, R.M., Bennett, D.A., Čukić, I., Deary, I.J., Hofer, S.M., Hoogendijk, E.O., Huisman, M., Johansson, B., Koval, A.V., van der Noordt, M., Piccinin, A.M., Rijnhart, J.J.M., Singh-Manoux, A., Skoog, J., Skoog, I., Starr, J., Vermunt, L., Clouston, S., Muniz-Terrera, G. (2018). Transitions across cognitive states and death among older adults in relation to education: a multi-state survival model using data from six longitudinal studies. Alzheimer's & Dementia, 14(4), 462-472. DOI: 10.1016/j.jalz.2017.10.003

Year: 
2018
Status: 
complete
Presentation Citations: 

Robitaille, A., Van den Hout A., Machado, R.J.M., Čukić, I., Deary, I.J., Hofer, S.M., Hoogendijke, E.O., Johansson, B., Koval, A.V., Van der Noordt, M., Piccinin, A.M., Rijnhart, J.J.M., Singh-Manoux, A., Skoog, J., Skoog, I., Vermunt, L., Muniz-Terrera, G. (2017, July). Transitions across Cognitive States and Mortality among Older Adults: A Multi-State Survival Model. Paper presented at the Alzheimer's Association International Conference (AAIC), London, UK.  

Hoogendijke, E.O., Robitaille, A., Van den Hout A., Machado, R.J.M., Čukić, I., Hofer, S.M., Johansson, B., Koval, A.V., Van der Noordt, M., Rijnhart, J.J.M., A., Skoog, J., Vermunt, L., Muniz-Terrera, G. (May, 2017). Transitions across cognitive states and mortality among older adults in relation to education. A multistate survival model using data from six longitudinal studies. Paper presented at the 29th REVES meeting, Santiago de Chile, Chile.

Abstract: 

Introduction: This study examines the role of educational attainment, an indicator of cognitive reserve, on transitions in later life between cognitive states (normal Mini-Mental State Examination (MMSE), mild MMSE impairment, and severe MMSE impairment) and death. Methods: Analysis of six international longitudinal studies was performed using a coordinated approach. Multistate survival models were used to estimate the transition patterns via different cognitive states. Life expectancies were estimated. Results: Across most studies, a higher level of education was associated with a lower risk of transitioning from normal MMSE to mild MMSE impairment but was not associated with other transitions. Those with higher levels of education and socioeconomic status had longer nonimpaired life expectancies. Discussion: This study highlights the importance of education in later life and that early life experiences can delay later compromised cognitive health. This study also demonstrates the feasibility and benefit in conducting coordinated analysis across multiple studies to validate findings.

Clouston et al., 2012. Benefits of educational attainment on adult fluid cognition

Clouston, S., Kuh, D., Herd, P., Elliott, J., & Richards, M., & Hofer, S. M. (2012). Benefits of educational attainment on adult fluid cognition: International evidence from three birth cohorts. International Journal of Epidemiology, 41,1729-1736. PMID: 23108707.

Year: 
2012
Status: 
complete
Presentation Citations: 

Clouston, S., Kuh, D., Richards, M., & Hofer, S.M. (August, 2012). The implications of educational benefits and propensity for educational attainment in health research. Paper presented at the 2012 Annual Meeting of the American Sociological Association, Denver.

Clouston, S., Richards, M., Kuh, D., & Hofer, S.M. (November, 2011). Selection and causation: The Educational benefit to cognition in later life. In S. M. Hofer & D. Kuh (Chairs), The life course determinants of physical, cognitive, and emotional functioning. Symposium conducted at the 64th Annual Scientific Meeting of the Gerontological Society of America, Boston, MA.

Hofer, S. M., & Clouston, S. (2011, October). Educational benefits in adult cognition: International evidence from three birth cohort studies. Paper presented at the annual meeting of the Society of Multivariate Experimental Psychology, Norman, OK.

Clouston, S., Kuh, D., Richards, M., Deary, I. J., Cooper, R., Hardy, R., & Hofer, S. M. (August, 2011). Inequalities in life course cognition: Class reproduction, cognitive selection, and educational advantage in HALCyon cohorts. Paper presented at the 2011 Annual Meeting of the American Sociological Association, Las Vegas.

Abstract: 

Background: Educational attainment is highly correlated with social inequalities in adult cognitive health; however, the nature of this correlation is in dispute. Recently, researchers have argued that educational inequalities are an artefact of selection by individual differences in prior cognitive ability, which both drives educational attainment and tracks across the rest of the life course. Although few would deny that educational attainment is at least partly determined by prior cognitive ability, a complementary, yet controversial, view is that education has a direct causal and lasting benefit on cognitive development.

Methods: We use observational data from three birth cohorts, with cognition measured in adolescence and adulthood. Ordinary least squares regression was used to model the relationship between adolescent cognition and adult fluid cognition and to test the sensitivity of our analyses to sample selection, projection and backdoor biases using propensity score matching.

Results: We find that having a university education is correlated with higher fluid cognition in adulthood, after adjustment for adolescent cognition. We do not find that adolescent cognition, gender or parental social class consistently modify this effect; however, women benefited more in the 1946 sample from Great Britain.

Conclusions: In all three birth cohorts, substantial educational benefit remained after adjustment for adolescent cognition and parental social class, offsetting an effect equivalent of 0.5 to 1.5 standard deviations lower adolescent cognition. We also find that the likelihood of earning a university degree depends in part on adolescent cognition, gender and parental social class. We conclude that inequalities in adult cognition derive in part from educational experiences after adolescence.

Clouston et al., 2014. The role of partnership status on late-life physical function.

Clouston, S. A., Lawlor, A., & Verdery, A. M. (2014). The role of partnership status on late-life physical function. Canadian Journal on Aging/La Revue Canadienne du Veillissement, 33(4), 413-425.

Year: 
2014
Status: 
complete
Abstract: 

This study examined the socioeconomic pathways linking partnership status to physical functioning, assessed using objective measures of late life physical functioning, including peak flow and grip strength. Using Wave 4 of the Survey of Health, Ageing and Retirement in Europe (SHARE), we ran multilevel models to examine the relationship between partnership status and physical function in late life, adjusting for social-network characteristics, socioeconomic factors, and health behaviours. We found a robust relationship between partnership status and physical function. Incorporating social-network characteristics, socioeconomic factors, and health behaviours showed independent robust relationships with physical function. Co-variates attenuated the impact of cohabitation, separation, and widowhood on physical function; robust effects were found for singlehood and divorce. Sex-segregated analyses suggest that associations between cohabitation, singlehood, divorce, and widowhood were larger for men than for women. Results suggest that social ties are important to improved physical function.

Der et al., 2010. Age-related changes in memory and fluid reasoning in a sample of healthy old people.

Der, G., Allerhand, M., Starr, J. M., Hofer, S. M., Deary, I. J. (2010). Age-related changes in memory and fluid reasoning in a sample of healthy old people. Aging, Neuropsychology, & Cognition, 17(1), 55-70.

Year: 
2010
Status: 
complete
Abstract: 

Participants in the Healthy Old People in Edinburgh (HOPE) study (N = 398) were assessed on Raven's Progressive Matrices and Logical Memory on up to three occasions. Covariates included education, social class, disease and medication status, blood pressure and study outcome. Raven's score declined linearly with age, whereas decline in Logical Memory was accelerating. There was significant variation in individuals' rates of decline for Ravens but not Logical Memory. Slope–intercept covariances were not significant. Those who later developed dementia already exhibited lower scores, more so for Logical Memory than Raven's. Death and study attrition were related to performance, again greater for Logical Memory. Conclusions: The HOPE approach of progressive screening is a feasible and practical method for studying healthy cognitive ageing. As predicted for an initially healthy sample, rates of decline were relatively homogeneous. The hypothesis of differential decline was not supported, nor was a strict interpretation of the hypothesis that cognitive ageing is entirely pathology driven.

Graham et al., 2015. Personality & Earnings Lost: The Economic Costs of Work Cut Back Days Due to Physical and Mental Health

Graham, E. K., Mroczek, D. K., & Elleman, L. G. (2015). Personality & earnings lost: The economic costs of work cut back days due to physical and mental health. International journal of personality psychology, 1(1), 1.

Year: 
2015
Status: 
complete
Abstract: 

Personality traits have emerged as significant contributors to physical and mental health, as well as various economic outcomes including income. Few studies have explored whether personality is related to the frequency of days lost on the job due to physical or mental health issues, and the subsequent economic losses as a result. The current study bridged the health, economic, and personality variables to determine whether personality was associated with earnings lost due to work cut back days from poor physical or mental health. We found, both concurrently and over a 10 year follow up, that high neuroticism and low openness were associated with more earnings lost due to mental health, while low extraversion was associated with more earnings lost due to physical health. These findings are interpreted in light of the effects that personality may have on an individual’s career and financial outcomes, and the economic effects of untreated physical and mental health problems.