Retiring from your full-time job might not be the best thing for your brain as you age, according to a new study out of Florida State University.
A team of researchers led by FSU Associate Professor of Sociology Dawn Carr found that people in so-called low-cognitive-complexity jobs, such as truck drivers and food prep workers, lose cognitive function more rapidly once they leave their 9-to-5 compared to people in high-cognitive-complexity jobs, such as financial managers or accountants.
The study was recently published in The Gerontologist.
“Our study supports a growing body of research that shows that challenging our brains is really good for us,” Carr said.
“As our population ages, there’s a growing need for older people to stay in the workforce longer.
It’s important to examine the benefits and consequences of longer working lives for the people who want to work well past the traditional retirement age of 65 and the growing number of people who, for financial reasons, need to delay their retirement.”
The research team used longitudinal data from the Health and Retirement Study to examine people over the age of 50 who went from working full time to completely retiring, partially retiring, or returning to work within a few years of retirement.
They compared individuals who made these retirement transitions with their counterparts who kept working full time.
Cognitive function was measured two years prior and two years following retirement using a two-part memory test.
They found that workers who retired from high-cognitive-complexity jobs had cognitive function that was just as good their continuously working counterparts regardless of which retirement pathway they chose.
In fact, those who retired from high-cognitive-complexity jobs and then returned to work, experienced slightly improved cognitive function.
“This result might mean that when these individuals started a new position after leaving their career jobs, they were able to learn new things and challenge their brains in beneficial ways,” Carr said.
However, not everyone benefited from leaving work and then returning.
Those who retired from low-cognitive-complexity work, even if they returned to work, experienced significant cognitive decline.
Those who remained employed full-time maintained their level of cognitive function.
“It seems that for individuals in this low-cognitive-complexity group, the type or amount of post-retirement activities they engaged in were insufficient for maintaining cognitive function,” Carr said.
“Our work and non-work lifestyles both influence how we use our brains over our entire lives.”
People who constantly learn new information are able to build more complex “cognitive scaffolding,” which provides more cognitive flexibility and resiliency, according to Carr. Those who instead engage in the same kinds of activities over and over, or do not challenge their brains, are less likely to develop protective cognitive networks.
Carr and her team encourage stakeholders to consider the groups that are more vulnerable to losing their cognitive function and identify interventions that may help them better maintain their cognitive health.
She suggests that there are not enough meaningful, cognitively challenging, non-full-time job opportunities for older workers.
Full-time employment is often coupled with important job-related benefits like health insurance, making a transition to part-time work inaccessible or unavailable for many older workers.
In addition, people with jobs that are physically demanding may be unable to continue working in these kinds of jobs and may need to be retrained for different kinds of positions.
“If we have more intention behind alternative work arrangements, it wouldn’t just benefit older people but younger people as well,” Carr said. “There’s a potential for these alternative work arrangements to help us maintain our health better, especially in later life.”
With the digitalisation of the society, cognitive functioning becomes more and more important for independent living in old age.
The proportion of older adults in most Western countries is increasing [1, 2] and at the same time, ageing is generally associated with a decline in cognitive functioning [3, 4].
Therefore, knowledge on factors affecting the rate of cognitive decline and how to maintain cognitive functioning in old age becomes increasingly relevant.
The use it or lose it hypothesis proposes that our cognitive functioning deteriorates when we are not challenged or stimulated mentally.
Accordingly, retirement can be expected to present a risk of accelerated cognitive decline due to a decrease in mentally challenging tasks following the exit from the labour market. However, the negative effect of retirement may differ between occupational groups.
Individuals in occupations with high mental demands would be expected to show less age related cognitive decline while still in the workforce than individuals in occupations with low mental demands.
According to the use it or lose it hypothesis, one would expect that the difference in rate of decline between these occupational groups would diminish after retirement, because their level of mental stimulation would become more similar.
In other words, the negative effect of retirement can be expected to be greater for individuals retiring from jobs with high mental demands.
On the other hand, the theory of cognitive reserve See [5, 6] proposes that some individuals have a larger cognitive reserve than others.
Two mechanisms behind this reserve are prosed:
1) Brain reserve which is a product of the brain anatomy so the larger brain and higher number of neurons and synapses an individual has, the larger the reserve.
2) Cognitive reserve reflects the extent to which an individual uses neural networks or cognitive paradigms efficiently and flexibly rather than anatomic differences [5, 6].
Cognitive reserve can be regarded as “the sum of its lifetime input” [7] (pp.617) and epidemiological studies suggest that educational level and occupational attainment can increase cognitive reserve [6, 8].
From this theoretical perspective, there are no differences in the rate of decline between individuals in occupations with high and low mental demands, only in the level of cognitive functioning.
In other words, they show parallel trajectories of cognitive decline, also referred to as preserved differentiation.
Accordingly, retirement would not affect the rate of cognitive decline in either of the two groups.
However, individuals with a larger reserve would reach the level of clinical impairment at a later stage because of their generally higher level of cognitive functioning.
The trajectories of the cognitive decline depend on whether it is fluid or crystallised cognitive abilities.
Fluid cognitive abilities include cognitive domains such as processing speed, working memory and spatial ability, while crystallised cognitive abilities include verbal ability and accumulated knowledge.
Singer et al. [9] found fluid ability to decline with age while crystallised ability remained stable until the age of 90 after which they found evidence of decline.
In addition, individual variance appears to increase with age for fluid but not crystallised cognitive ability [10, 11].
Based on this, it could be speculated that the potential detrimental effect of retirement will differ depending on whether it is fluid or crystallised abilities that are being measured.
Results from cross sectional studies suggest that there is a negative association between retirement and cognitive functioning [8, 12].
A limitation of cross sectional designs is that they are not able to provide evidence for a causal relationship. To overcome this problem, Rohwedder and Willis [13] used cross sectional data from various countries with different retirement ages.
These aggregated data showed that drop in memory functioning matched the age of retirement in the respective countries.
This pattern of results, they argue, provide evidence for a causal relationship between retirement and drop in memory functioning.
However, the results from cross sectional designs only informs about differences in cognitive functioning, not changes in cognitive functioning over time because they only measure cognitive functioning at one point in time.
It is therefore not possible to draw any conclusions on whether retirement affects the rate of cognitive decline based on results from studies using a cross sectional design. To answer this question, it is necessary to gather evidence from studies using a longitudinal design examining changes in cognitive functioning over time.
A review of longitudinal studies examining whether psychosocial work conditions can protect against cognitive decline did not find clear evidence that mental demands at work protect against cognitive decline (in neither crystallised nor fluid abilities) while still in the workforce [14], however, this study did not examine the impact of retirement on cognitive decline.
To the authors’ knowledge, no study so far has gathered the evidence from longitudinal studies on the impact of retirement on cognitive decline. Thus, a systematic overview of the knowledge on the impact of retirement on cognitive decline is still lacking.
Therefore, in the current article, we set out to answer the following research question:
Does retirement affect age related cognitive decline?
To answer this question we carried out a systematic literature review of longitudinal studies on the impact of retirement on cognition, gathering the evidence for the impact of retirement on cognitive functioning and/or the rate of change in cognitive functioning, assessing the evidence separately for fluid and crystallised cognitive abilities.
In addition, we investigated if the association between retirement and cognitive functioning and/or rate of cognitive decline differed between occupations with different levels of cognitive demands.
Results
A total of seven articles were included in the quality assessment. See Table Table22 for an overview of the seven studies (an overview of the points given for each item on the quality checklist for each study is available from the authors on request).
Table 2
Overview of the seven studies included
| Reference | Population | Exposure and confounders controlled for | Outcome | Follow up | Results |
|---|---|---|---|---|---|
| Andel et al. (2015) [21] | The US Health and Retirement Study (HRS). general population aged 55+ at baseline (n = 3779) | Self-reported retirement. Comparing the trajectories of cognitive change of participants with high and low job strain before and after retirement. Control for age, gender, education, marital status, race, income, length of occupation, depressive symptoms, cardiovascular disease, manual/non-manual work. | Episodic memory (immediate and delayed recall test). (F)b | 10 data collection points at 2 years intervals. The participants averaged 7.4 interviews; 3.8 before retirement, 4.4 after retirement. | Growth curve model parameter estimates: Pre-retirement change was significant (−5.72, p > 0.01) Post-retirement change was not significant (0.92, p = 0.75) Greater job strain associated with worse episodic memory (−0.49, p < 0.001); not associated with pre-retirement change in episodic memory (0.39, p = 0.181); associated with greater decline in episodic memory post retirement (−0.65, p < 0.05). |
| Bonsang et al. (2012) [22] | The US Health and Retirement Study (HRS). General population aged 51–75 (n = 14,710) | Self-reported retirement (year and month when last employment ended). Compare retired with average score of sample. In the model they include eligibility for social security to provide evidence against reverse causality and they control for time in-variant heterogeneity. | Episodic memory (10 word recall test –immediate and delayed) (F) Working memory (subtract 7 from 100 up to five times). (F) | 6 data collection points at 2 years intervals. Length of retirement included. | Retirement for one year or more has a negative effect on episodic memory score(Coefficient estimate: −0.942: 95%-confidence interval: −1.61 to −0.28). Magnitude of effect: −0.278, SE 0.100. Working memory: (coefficient estimate −0.279, SE 0.126). Magnitude of effect −0.230, SE 0.104 (p < 0.05). |
| Finkel et al. (2009) [29] | Swedish Adoption/twin study of Aging (SATSA). Twins aged 55+ (n = 462) | Self-reported year of retirement). Comparing slope of cognitive change before and after retirement, and comparing the trajectories of high and low complexity occupations. Control for dementia and practice effect. | Spatial ability (Figure Logic, Block design, Card Rotation) (F) Verbal ability (Information, Synonymous, Analogies) (C)b Memory (Digit Span, Picture Memory, Names & Faces) (F) Processing speed (Symbol Digit and Figure Identification) (F) | 5 measure points at 3 years intervals (one 7 years) Length of retirement measured (15 years before retirement to 20 years after retirement modelled). | Growth curve model parameter estimates: Verbal ability: Mean at retirement: (L)a: 53.7; (H)a: 55.3 (ns); pre-retirement change: (L): −0.13; (H): +0.07 (p < 0.05). Post retirement change: (L):-0.1: (H): −0.2 (ns). Spatial ability: Mean at retirement: (L): 51.36; (H): 54.36 (p < 0.05); pre-retirement change (L): −0.35, (H): −0.35 (ns); post retirement change (L): −0.29; (H): −0.51 (p < 0.05). Memory: So significant findings. Processing speed: Mean at retirement: (L): 52.93; (H): 55.47 (p < 0.05); pre-retirement change: (L): −0.27; (H): −0.52 (ns); post retirement change: (L): −0.60; (H): −0.69 (ns). |
| Fisher et al. (2014) [24] | US Health and Retirement Study (HRS). General population aged 51–61 at entry (n = 4182) | Self-report of year and month of retirement. Comparing rate of cognitive change before and after retirement, and comparing the trajectories of high and low mental demand occupations. Control for practice effect and socioeconomic, demographic, and health variables. | Episodic memory (immediate and delayed word recall test) (F) Mental status (telephone Interview of Cognitive Status) | Data from 1992 to 2010 collected at 2 years intervals. Participants included if completed min. 2 waves. Length of retirement included. (Mental status only post retirement measures) | Episodic memory: Difference in pre- and postretirement decline (Estimate = 0.06; p < 0.05). Higher mental demands associated with better memory (Estimate = 0.06; p < 0.05) and less steep decline (Estimate = 0.01; p < 0.05). Mental status: Higher mental demands associated with better cognitive status at point of retirement (Estimate = 0.11; p < 0.05). There was a general decline of 0.27 SD per 10 years post retirement. Higher mental work demands was associated with slower rate of decline (Estimate = 0.004; p < 0.05). |
| Roberts et al. (2010) [25] | The UK Whitehall II study. London-based civil servants aged 38–60 at entry (n = 2031) | Employment status. (still working vs fully retired at follow up, all working at baseline). Difference between baseline and follow up cognitive score comparing retirees and those still working. Control for adult IQ, age, mental and physical health, self-rated health, social class, education, psychosocial job characteristics, and leisure activities. | Short term verbal memory (free recall test) (F) Inductive reasoning (AH4 – part 1) (F) Verbal fluency (“s” words and animal names) (F) | 5 years (159 had been retired between <1–115 weeks at follow up; 151 between 115 and 218 weeks; 160 between 219 and 309 weeks) | General trend of improved cognitive functioning at follow up. Inductive reasoning: retirees less improvement than those still working (Regression coefficient − 0.7; 95% CI −1.2 to −0.09). Short term verbal memory: no significant findings Verbal fluency: no significant findings |
| Wickrama et al. (2013) [26] | US HRS (Health and retirement study). General population aged 62+ at entry (n = 8524) | Self-reported work status: working full-time, working part-time, fully retired. They use structural equation models to investigate the reciprocal association between change in work status and cognitive change. Control for age, education, gender, race/ethnicity, depressive symptoms and physical disability. | Immediate memory (Recall from 10-word lists) (F) | 6 data collection points at 2 years intervals. No information on length of retirement period. | Over three time intervals the level of working at one point in time predicted subsequent changes in immediate memory (β = .04, & .06, both p < 0.01, and β = .07, p < 0.001). |
| Ryan (2008) [27] | The Seattle Longitudinal Study (SLS). White middle and upper class individuals aged 60+ at entry (n = 271) | Work status (retired vs working). Comparing the cognitive scores of those working all three waves with those retiring during study. Control for gender, education, perceptual speed, subjective and objective health. | Verbal memory (PMA, immediate recall, delayed recall) (F) Inductive reasoning (PMA, ADEPT, word series, number series) (F) Verbal ability (PMA, ETS) (C) | 3 data collection points at 7 years intervals. Length of retirement not measured. | Inductive reasoning: Participants employed in all three waves averaged 0.14 t-score units higher than those who worked only during one or two waves (p < 0.05). Verbal ability:Working more than one wave was associated with a 2.4 t-score unit gain (p < 0.01). Verbal ability: No significant findings |
a H high complexity with people jobs, L low complexity with people jobs. b(F) Fluid cognitive ability, (C) Crystallised cognitive ability
All seven of the studies included measures of fluid cognitive abilities, two of the studies also included measures of crystallised cognitive abilities.
Review of the seven studies that included measures of fluid cognitive abilities
Andel et al. [21] compared the trajectories of cognitive change of participants with high and low job strain respectively. They found that rate of cognitive decline before retirement was significant while the rate of cognitive decline after retirement was not, indicating a positive effect of retirement. In addition, they found that job strain was not associated with the rate of cognitive change before retirement, but after retirement, job strain was associated with greater decline in episodic memory, indicating that retirement has a less positive effect on participants who experience greater job strain. However, they did not directly assess the impact of retirement, so the results should be interpreted with caution. They control for socioeconomic, demographic, and health variables, but not for practice effect. We categorised the study as of high quality.
Bonsang et al. [22] compared the scores from the retired individuals with the average score of the sample and found that retirement was associated with an approximately 10% decrease in memory scores. However, they do not provide information on the impact of retirement on the rate of cognitive decline. We interpreted the effect size to be small. The study lacks information on drop out and it is therefore difficult to assess the risk of selection bias due to drop out. We categorised the study as moderate quality.
Finkel et al. [23] compared participants working in jobs with high and low complexity with people on cognitive performance and change in cognitive performance before and after retirement. They found that retirement was associated with an accelerated decline in processing speed for both job categories and an accelerated decline in spatial ability for participants retiring from high complexity jobs but not those retiring from low complexity jobs. They did not find any significant results for their third measure of fluid ability. We interpreted all effect sizes to be small. They also compared individuals retiring from jobs with high/low complexity with data and things, but did not find significant results. They control for practice effect and dementia. We assessed the study as being of moderate quality.
Fisher et al. [24] compared the results of participants retiring from jobs with high mental demands with participants retiring from jobs with lower mental demands on the rate of cognitive change before and after retirement. They found a decrease in memory score in the years leading up to retirement and a slightly less steep decline in memory score after retirement, indicating a positive effect of retirement on the rate of cognitive change. We interpreted the effect sizes to be small. Participants retiring from jobs with higher mental demands showed slightly higher performance and less steep decline both before and after retirement. Sample attrition may have affected the results. However, they control for socioeconomic, demographic, and health variables as well as practice effect. We categorised the study as of high quality in the quality assessment.
Roberts et al. [25] compared retired and those still working on the difference between the baseline score and the follow-up score. They found a general trend of improved cognitive functioning at follow-up. Participants who were retired generally showed less improvement than those still working, indicating a negative effect of retirement on the rate of cognitive change. However, this trend was only statistically significant for one out of their three measures of fluid ability and the effect sizes are small. They control for adult IQ, age, mental and physical health, self-rated health, social class, education, psychosocial job characteristics, and leisure activities. However, the results may have been biased both due to practice effect and drop outs. We rated the study as being of moderate quality.
Wickrama et al. [26] investigated the reciprocal association between change in work status and cognitive change. They found that work status predicted change in performance on the immediate memory test at follow-up sessions. Thus indicating that reduced working hours and retirement lead to decline in immediate memory. Again we interpreted the effect sizes as being small. They control for spurious findings due to common methods variance by including depressive symptoms and physical disability in their analyses. In addition, they control for age, education, gender, and race/ethnicity. However, they do not mention how they deal with drop outs or practice effect on the tests. It is therefore not possible to rule out that the results are biased due to these two factors. We categorised the study as of moderate quality.
Ryan [27] compared the cognitive scores of those working all three waves with those retiring during the study. She found a slight decline in performance for every increased year of age in all three cognitive domains she included. Retirement was associated with lower performance on one of the two measures of fluid ability. She did not directly assess the impact of retirement on the rate of decline, but from the results it appears that there is no difference in the rate of change between the groups. We interpreted the effect sizes to be small. She controls for gender, education, perceptual speed, subjective and objective health. The results can only be generalised to upper and middle class white Americans. T-tests show that drop outs had lower scores on verbal ability and processing speed, but there was no statistical significant difference on educational attainment, inductive reasoning or verbal memory. We categorised the study as of moderate quality.
Synthesis of the evidence for the effect of retirement on the rate of change in fluid cognitive abilities
The evidence of the effect of retirement on rate of change in fluid cognitive abilities is conflicting.
One study of moderate quality [26] provides weak evidence of a negative effect of retirement on the rate of decline in fluid cognitive abilities indicating that retirement accelerates the rate of cognitive decline.
In addition, two studies of moderate quality have internally inconsistent results. They both get a mix of not significant results on some measures of fluid cognitive abilities and a negative effectof retirement on cognitive decline [23, 25] on other of their measures of fluid cognitive abilities.
Two studies of high quality [21, 24] provide strong evidence of a positive effect of retirement on rate of cognitive decline in fluid cognitive abilities indicating that retirement slows down the rate of cognitive decline. Individuals retiring from jobs with high mental demands [24] and individuals who experienced low job strain [21] in particular appear to experience a positive effect of retirement.
Synthesis of the evidence for the effect of retirement on fluid cognitive functioning
One study of moderate quality [22] provides weak evidence of a negative effect of retirement on fluid cognitive functioning indicating that retirement leads to a drop in cognitive functioning.
In addition, one study of moderate quality has internally inconsistent results. It has a mix of not significant results on some measures of fluid cognitive abilities and a negative effect of retirement on cognitive functioning [27] on other of their measures of fluid cognitive abilities.
Review of the two studies that included measures of crystallised cognitive abilities
Finkel et al. [23] (moderate quality) included one measure of crystallised abilities, verbal ability, and found a statistical significant difference in cognitive change before retirement where participants in high complexity jobs show an increase in ability while participants in low complexity jobs show a decrease. After retirement no statistical significant difference in cognitive change between participants in high and low complexity jobs was found, indicating that only participants in high complexity jobs experience a negative effect of retirement. We interpreted the effect sizes to be small. (Please find the more throughout description of the study under the review of studies including fluid abilities).
Ryan [27] (moderate quality) includes one measures of crystallised abilities, verbal ability, and found a slight decline in cognitive performance for every increased year of age. Retirement was associated with lower performance. She did not directly assess the impact of retirement on the rate of decline, but from the results it appears that there is no difference in the rate of change between the groups. We interpreted the effect sizes to be small. (Please find the more throughout description of the study under the review of studies including fluid abilities).
Synthesis of the evidence for the effect of retirement on rate of change in crystallised cognitive abilities
One study of moderate quality [23] provides weak evidence for a negative effect of retirement on rate of decline in crystallised cognitive abilities indicating that retirement accelerates the rate of cognitive decline, but only for individuals retiring from jobs with high complexity with people.
Synthesis of the evidence for the effect of retirement on crystallised cognitive functioning
One study of moderate quality [27] provides weak evidence of a negative effect of retirement on crystallised cognitive functioning indicating that retirement is associated with a drop in cognitive functioning among high SES individuals.
More information: Dawn C Carr et al. Alternative Retirement Paths and Cognitive Performance: Exploring the Role of Preretirement Job Complexity, The Gerontologist (2019). DOI: 10.1093/geront/gnz079
Provided by Florida State University
