Reaction Time Explains IQ's Association with Death

Learning how network structure shapes decision-making for bio-inspired computing

To better understand how network structure shapes intelligent behavior, we developed a learning algorithm that we used to build personalized brain network models for 650 Human Connectome Project participants. We found that participants with higher intelligence scores took more time to solve difficult problems, and that slower solvers had higher average functional connectivity. With simulations we identified a mechanistic link between functional connectivity, intelligence, processing speed and brain synchrony for trading accuracy with speed in dependence of excitation-inhibition balance. Reduced synchrony led decision-making circuits to quickly jump to conclusions, while higher synchrony allowed for better integration of evidence and more robust working memory. Strict tests were applied to ensure reproducibility and generality of the obtained results. Here, we identify links between brain structure and function that enable to learn connectome topology from noninvasive recordings and map it to inter-individual differences in behavior, suggesting broad utility for research and clinical applications.

Proportional Changes in Cognitive Subdomains During Normal Brain Aging

Background: Neuroscience lacks a reliable method of screening the early stages of dementia. Objective: To improve the diagnostics of age-related cognitive functions by developing insight into the proportionality of age-related changes in cognitive subdomains. Materials and Methods: We composed a battery of psychophysiological tests and collected an open-access psychophysiological outcomes of brain atrophy (POBA) dataset by testing individuals without dementia. To extend the utility of machine learning (ML) classification in cognitive studies, we proposed estimates of the disproportional changes in cognitive functions: an index of simple reaction time to decision-making time (ISD), ISD with the accuracy performance (ISDA), and an index of performance in simple and complex visual-motor reaction with account for accuracy (ISCA). Studying the distribution of the values of the indices over age allowed us to verify whether diverse cognitive functions decline equally throughout life or there is a divergence in age-related cognitive changes. Results: Unsupervised ML clustering shows that the optimal number of homogeneous age groups is four. The sample is segregated into the following age-groups: Adolescents ∈ [0, 20), Young adults ∈ [20, 40), Midlife adults ∈ [40, 60) and Older adults ≥60 year of age. For ISD, ISDA, and ISCA values, only the median of the Adolescents group is different from that of the other three age-groups sharing a similar distribution pattern (p > 0.01). After neurodevelopment and maturation, the indices preserve almost constant values with a slight trend toward functional decline. The reaction to a moving object (RMO) test results (RMO_mean) follow another tendency. The Midlife adults group's median significantly differs from the remaining three age subsamples (p < 0.01). No general trend in age-related changes of this dependent variable is observed. For all the data (ISD, ISDA, ISCA, and RMO_mean), Levene's test reveals no significant changes of the variances in age-groups (p > 0.05). Homoscedasticity also supports our assumption about a linear dependency between the observed features and age. Conclusion: In healthy brain aging, there are proportional age-related changes in the time estimates of information processing speed and inhibitory control in task switching. Future studies should test patients with dementia to determine whether the changes of the aforementioned indicators follow different patterns.

Cognitive test scores vary with choice of personal digital device

Mobile- and web-based psychological research are a valuable addition to the set of tools available for scientific study, reducing logistical barriers for research participation and allowing the recruitment of larger and more diverse participant groups. However, this comes at the cost of reduced control over the technology used by participants, which can introduce new sources of variability into study results. In this study, we examined differences in measured performance on timed and untimed cognitive tests between users of common digital devices in 59,587 (Study 1) and 3818 (Study 2) visitors to TestMyBrain.org , a web-based cognitive testing platform. Controlling for age, gender, educational background, and cognitive performance on an untimed vocabulary test, users of mobile devices, particularly Android smartphones, showed significantly slower performance on tests of reaction time than users of laptop and desktop computers, suggesting that differences in device latency affect measured reaction times. Users of devices that differ in user interface (e.g. screen size, mouse vs. touchscreen) also show significant differences (p < 0.001) in measured performance on tests requiring fast reactions or fine motor movements. By quantifying the contribution of device differences to measured cognitive performance in an online setting, we hope to improve the accuracy of mobile- and web-based cognitive assessments, allowing these methods to be used more effectively.

The evolutionary genetics of personality

Genetic influences on personality differences are ubiquitous, but their nature is not well understood. A theoretical framework might help, and can be provided by evolutionary genetics. We assess three evolutionary genetic mechanisms that could explain genetic variance in personality differences: selective neutrality, mutation‐selection balance, and balancing selection. Based on evolutionary genetic theory and empirical results from behaviour genetics and personality psychology, we conclude that selective neutrality is largely irrelevant, that mutation‐selection balance seems best at explaining genetic variance in intelligence, and that balancing selection by environmental heterogeneity seems best at explaining genetic variance in personality traits. We propose a general model of heritable personality differences that conceptualises intelligence as fitness components and personality traits as individual reaction norms of genotypes across environments, with different fitness consequences in different environmental niches. We also discuss the place of mental health in the model. This evolutionary genetic framework highlights the role of gene‐environment interactions in the study of personality, yields new insight into the person‐situation‐debate and the structure of personality, and has practical implications for both quantitative and molecular genetic studies of personality. Copyright © 2007 John Wiley & Sons, Ltd.

Is Reaction Time Slowing an Early Sign of Alzheimer's Disease? A Meta-Analysis

BACKGROUND

Although simple reaction time (SRT) slowing is associated with dementia in Alzheimer's disease (AD), its presence in individuals with mild cognitive impairment (MCI) is subject to debate.

OBJECTIVE

The aim of this study was to perform a systematic review and meta-analysis of the literature data on SRT slowing in MCI.

METHODS

Publications with data on SRT, age, and educational level in participants with MCI were included. After calculating the log SRT and its variance for each study, we took interstudy heterogeneity into account by conducting a random effects (restricted maximum likelihood estimation) meta-analysis.

RESULTS

The 7 selected studies featured a total of 327 participants with MCI and 468 healthy controls (HCs). The mean age was 68.2 years for participants with MCI and 72.3 years for HCs. The weighted mean Mini-Mental State Examination score was 26.4 in the MCI group, and 28.4 in the HC group. The mean SRT was significantly (p = 0.0217) longer in the MCI group (by 11%) than in the HC group.

CONCLUSION

This meta-analysis showed that SRTs are longer in individuals with MCI. Further studies are needed to determine the mechanism of SRT slowing, its anatomical correlates, and a threshold value for diagnosing prodromal AD.

The Face of Early Cognitive Decline? Shape and Asymmetry Predict Choice Reaction Time Independent of Age, Diet or Exercise

Slower reaction time is a measure of cognitive decline and can occur as early as 24 years of age. We are interested if developmental stability predicts cognitive performance independent of age and lifestyle (e.g., diet and exercise). Developmental stability is the latent capacity to buffer ontogenetic stressors and is measured by low fluctuating asymmetry (FA). FA is random—with respect to the largest side—departures from perfect morphological symmetry. The degree of asymmetry has been associated with physical fitness, morbidity, and mortality in many species, including humans. We expected that low FA (independent of age, diet and exercise) will predict faster choice reaction time (i.e., correct keyboard responses to stimuli appearing in a random location on a computer monitor). Eighty-eight university students self-reported their fish product consumption, exercise, had their faces 3D scanned and cognitive performance measured. Unexpectedly, increased fish product consumption was associated with worsened choice reaction time. Facial asymmetry and multiple face shape variation parameters predicted slower choice reaction time independent of sex, age, diet or exercise. Future work should develop longitudinal interventions to minimize early cognitive decline among vulnerable people (e.g., those who have experienced ontogenetic stressors affecting optimal neurocognitive development).

Reaction time variability and brain white matter integrity

Objective: Mean speed of responding is the most commonly used measure in the assessment of reaction time (RT). An alternative measure is intraindividual variability (IIV): the inconsistency of responding across multiple trials of a test. IIV has been suggested as an important indicator of central nervous system functioning, and as such, there has been increasing interest in the associations between IIV and brain imaging metrics. Results however, have been inconsistent. The present seeks to provide a comprehensive evaluation of the associations between a variety of measures of brain white matter integrity and individual differences in choice RT (CRT) IIV. Method: MRI brain scans of members of the Lothian Birth Cohort 1936 were assessed to obtain measures of the volume and severity of white matter hyperintensities, and the integrity of brain white matter tracts. CRT was assessed with a 4 CRT task on a separate occasion. Data were analyzed using multiple regression (N range = 358–670). Results: Greater volume of hyperintensities and more severe hyperintensities in frontal regions were associated with higher CRT IIV. White matter tract integrity, as assessed by both fractional anisotropy and mean diffusivity, showed the smallest effect sizes in associations with CRT IIV. Associations with hyperintensities were attenuated and no longer significant after controlling for M CRT. Conclusions: Taken together, the results of the present study suggested that IIV was not incrementally predictive of white matter integrity over mean speed. This is in contrast to previous reports, and highlights the need for further study.

Variability in speeded cognitive test performance has been argued to be a potential early marker of cognitive decline and progression into mild cognitive impairment in aging. Evidence as to the robustness of the relationship, and the potential neurological underpinnings is varied. Our results suggest that average speeded performance, not variability, may be more reliably related to various measures of the brain. These findings are in contrast to much of the extant literature, highlighting the need for further research.

Neural correlates of anticipatory cardiac deceleration and its association with the speed of perceptual decision-making, in young and older adults

Warning stimuli in sensorimotor tasks induce a state of preparedness characterized by increased alertness, focused attention and immobility. This state of attentive anticipation is associated with heart rate deceleration. Ageing affects the amplitude of the anticipatory cardiac deceleration responses; yet, the impact of this physiological change on cognitive performance is still to be elucidated. In fact, how cardiac deceleration relates to brain function and cognitive performance in the context of perceptual decision-making and different levels of decision complexity remains unknown. Here, we aimed to investigate the relationship between cardiac deceleration, brain function, and performance in perceptual decision tasks and how these associate with age-related changes. We measured simultaneously the electrocardiogram, the pupilogram, and the electroencephalogram in 36 young and 39 older adults, while they were engaged in two auditory cued reaction time tasks: a detection task and a go/no-go task requiring inhibitory control. We observed robust cardiac deceleration responses that increased with increasing task complexity. Notably, stronger modulation of the cardiac response across tasks was associated with the ability to maintain response speed as decision complexity increased suggesting a link between cardiac deceleration and facilitation of perceptual decisions. Additionally, cardiac deceleration appears to have a cortical origin as it correlated with frontocentral event-related potentials. In contrast, beta oscillations at baseline and task-related beta suppression were not predictive of cardiac deceleration suggesting a dissociation between sensorimotor oscillatory activity and this cardiac response. Importantly, we found age-related changes in anticipatory cardiac deceleration associated with deficits in perceptual decision-making.

A Comprehensive Comparison of Quantifications of Intraindividual Variability in Response Times: A Measurement Burst Approach

OBJECTIVES

To formally identify and contrast the most commonly-employed quantifications of response time inconsistency (RTI) and elucidate their utility for understanding within-person (WP) and between-person (BP) variation in cognitive function with increasing age.

METHOD

Using two measurement burst studies of cognitive aging, we systematically identified and computed five RTI quantifications from select disciplines to examine: (a) correlations among RTI quantifications; (b) the distribution of BP and WP variation in RTI; and (c) the comparability of RTI quantifications for predicting attention switching.

RESULTS

Comparable patterns were observed across studies. There was significant variation in RTI BP as well as WP across sessions and bursts. Correlations among RTI quantifications were generally strong and positive both WP and BP, except for the coefficient of variation. Independent prediction models indicated that slower mean response time (RT) and greater RTI were associated with slower attention switching both WP and BP. For selecting simultaneous prediction models, collinearity resulted in inflated standard errors and unstable model estimates.

DISCUSSION

RTI reflects a novel dimension of performance that is a robust and theoretically informative predictor of BP and WP variation in cognitive function. Among the plenitude of RTI quantifications, not all are interchangeable, nor of comparable predictive utility.

Cognitive function in adolescence and the risk for premature diabetes and cardiovascular mortality in adulthood

Background

Epidemiological studies have demonstrated a relationship between cognitive function in youth and the future risk of death. Less is known regarding the relationship with diabetes related death. This study assessed the relationship between cognitive function in late adolescence and the risk for diabetes, cardiovascular- (CVD) and all-cause mortality in adulthood.

Methods

This retrospective study linked data from 2,277,188 16–19 year olds who had general intelligence tests (GIT) conducted during pre-military recruitment assessment with cause of death as coded by the Israel Central Bureau of Statistics. The associations between cognitive function and cause-specific mortality were assessed using Cox models.

Results

There were 31,268 deaths that were recorded during 41,916,603 person-years of follow-up, with a median follow-up of 19.2 (IQR 10.7, 29.5) years. 3068, 1443, 514 and 457 deaths were attributed to CVD, CHD, stroke, and diabetes, respectively. Individuals in the lowest GIT vs. highest GIT quintiles in unadjusted models had the highest risk for all-cause mortality (HR 1.84, 95% CI 1.78, 1.91), total CVD (HR 3.32, 95% CI 2.93, 3.75), CHD (HR 3.49 95% CI 2.92, 4.18), stroke (HR 3.96 95% CI 2.85, 5.5) and diabetes-related (HR 6.96 95% CI 4.68, 10.36) mortality. These HRs were attenuated following adjustment for age, sex, birth year, body-mass index, residential socioeconomic status, education and country of origin for all-cause (HR 1.23, 95% CI 1.17, 1.28), CVD (HR 1.76, 95% CI 1.52, 2.04), CHD (HR 1.7 95% CI 1.37, 2.11), stroke (HR 2.03, 95% CI 1.39, 2.98) and diabetes-related (HR 3.14 95% CI 2.00, 4.94) mortality. Results persisted in a sensitivity analyses limited to participants with unimpaired health at baseline and that accounted competing risk.

Conclusions

This analysis of over 2 million demonstrates a strong relationship between cognitive function at youth and the risk for diabetes, all-cause and CVD-related mortality independent of adolescent obesity.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0798-5) contains supplementary material, which is available to authorized users.

Understanding the relationship between cognition and death: a within cohort examination of cognitive measures and mortality

Despite several studies demonstrating an independent and inverse association between cognition and mortality, the nature of this association still remains unclear. To examine the association of cognition and mortality after accounting for sociodemographic, health and lifestyle factors and to explore both test and population characteristics influencing this relationship. In a population based cohort of 8585 men and women aged 48-92 years, who had cognitive assessments in 2006-2011 and were followed up till 2016 for mortality, we examined the relationship between individual cognitive tests as well as a global cognition score to compare their ability in predicting mortality and whether these differed by population characteristics. Risk of death was estimated using Cox proportional hazard regression models including sociodemographic, lifestyle and health variables, and self-reported comorbidities, as covariates in the models. Poor cognitive performance (bottom quartile of combined cognition score) was associated with higher risk of mortality, Hazard Ratio = 1.32 (95% Confidence Interval 1.09, 1.60); individual cognitive tests varied in their mortality associations and also performed differently in middle-age and older age groups. Poor cognitive performance is independently associated with higher mortality. This association is observed for global cognition and for specific cognitive abilities. Associations vary depending on the cognitive test (and domain) as well as population characteristics, namely age and education.

Reaction times match IQ for major causes of mortality: Evidence from a population based prospective cohort study

Introduction

The association of premorbid cognitive ability with all-cause mortality is now well established. However, since all-cause mortality is relatively uninformative about aetiology, evidence has been sought, and is beginning to accumulate, for associations with specific causes of mortality. Likewise, the underlying causal pathways may be illuminated by considering associations with different measures of cognitive ability. For example, critics of IQ type measures point to possible cultural or social biases and there is, consequently, a need for more culturally neutral measures such as reaction times. We examine the associations of cognitive ability with major causes of mortality, including: cardiovascular disease, cancer and respiratory disease and compare the results for a standard IQ test, the Alice Heim 4 (AH4), with those for simple and four-choice reaction times.

Methods

Data were derived from the oldest cohort of the West of Scotland Twenty-07 Study. Participants were randomly sampled from the Central Clydeside Conurbation, a mainly urban area centred on Glasgow city. At baseline, aged 56, they were interviewed in their homes by trained interviewers; the AH4 was administered and reaction times measured using a portable electronic device. Vital status was ascertained via linkage to the NHS central register. Cox regression was used in SAS 9.4 for the main analyses. Adjustments were made for sex, smoking status and social class.

Results

Full data on AH4, RT and covariates were available for 1350 out of 1551. During 29 years of follow-up, there were 833 deaths: 279 cardiovascular disease (CVD) (168 CHD; 68 stroke); 291 cancer; 97 respiratory disease; 42 digestive disease; and 39 dementia. The 85 remaining deaths were a heterogeneous mixture with no cause accounting for more than 14.

AH4 scores were associated with most major causes. Digestive disease and dementia had similar effect sizes but were not significant. Within cardiovascular disease, there was an association with coronary heart disease but not stroke. The association with cancer was primarily due to those cancers related to smoking.

RT measures were mostly associated with the same causes of death. Where significant, effects were in the same directions and of similar magnitude. That is, lower AH4 scores, longer reaction times, and more variable reaction times were all associated with increased mortality risk from the major causes of death. A summary measure of RT outperformed the AH4 for most causes.

Conclusion

The association between intelligence with mortality from the major causes is also seen with reaction times. That effect sizes are of similar magnitude is suggestive of a common cause. It also implies that the association of cognitive ability with mortality is unlikely to be due to any social, cultural or educational biases that are sometimes ascribed to intelligence measures.

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Intelligence and reaction times are both associated with most major causes of mortality

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Effect sizes are of similar magnitude

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A summary RT measure provides the more parsimonious explanation for most causes

Childhood IQ and mortality during 53 years' follow-up of Swedish men and women

BACKGROUND

The association between childhood cognitive ability measured with IQ tests and mortality is well documented. However, studies on the association in women are few and conflicting, and the mechanisms underlying the association are unclear.

METHODS

Data on IQ were collected at school at age 13 among 19 919 men and women born in 1948 and 1953. Information on childhood socioeconomic position, the participants' socioeconomic and social circumstances in middle age and mortality up to 2013 was collected through national registers.

RESULTS

Lower IQ was associated with an increased risk of all-cause mortality among men (1070 cases, HR 1.31, 95% CI 1.23 to 1.39 for one SD decrease in IQ) and among women (703 cases, HR 1.16, 95% CI 1.08 to 1.25). IQ was associated with mortality from several causes of death in men, and cancer and cardiovascular disorder mortality in women. Adjustment for socioeconomic factors in childhood and, in particular, in adulthood attenuated the associations considerably in men and near completely in women.

CONCLUSION

Lower IQ was associated with an increased risk of mortality in men and women. The explanatory effects of socioeconomic factors in adulthood suggest that they constitute an important pathway in the association between IQ and mortality, especially in women.

Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function

General cognitive function is a prominent and relatively stable human trait that is associated with many important life outcomes. We combine cognitive and genetic data from the CHARGE and COGENT consortia, and UK Biobank (total N = 300,486; age 16-102) and find 148 genome-wide significant independent loci (P < 5 × 10-8) associated with general cognitive function. Within the novel genetic loci are variants associated with neurodegenerative and neurodevelopmental disorders, physical and psychiatric illnesses, and brain structure. Gene-based analyses find 709 genes associated with general cognitive function. Expression levels across the cortex are associated with general cognitive function. Using polygenic scores, up to 4.3% of variance in general cognitive function is predicted in independent samples. We detect significant genetic overlap between general cognitive function, reaction time, and many health variables including eyesight, hypertension, and longevity. In conclusion we identify novel genetic loci and pathways contributing to the heritability of general cognitive function.

Intelligence and all-cause mortality in the 6-Day Sample of the Scottish Mental Survey 1947 and their siblings: testing the contribution of family background

Background

Higher early-life intelligence is associated with a reduced risk of mortality in adulthood, though this association is apparently hardly attenuated when accounting for early-life socio-economic status (SES). However, the use of proxy measures of SES means that residual confounding may underestimate this attenuation. In the present study, the potential confounding effect of early-life SES was instead accounted for by examining the intelligence-mortality association within families.

Methods

The association between early-life intelligence and mortality in adulthood was assessed in 727 members of the 6-Day Sample of the Scottish Mental Survey 1947 and, for the first time, 1580 of their younger siblings. These individuals were born between 1936 and 1958, and were followed up into later life, with deaths recorded up to 2015. Cox regression was used to estimate the relative risk of mortality associated with higher IQ scores after adjusting for shared family factors.

Results

A standard-deviation advantage in IQ score was associated with a significantly reduced mortality risk [hazard ratio = 0.76, p < 0.001, 95% confidence interval (CI) (0.68-0.84)]. This reduction in hazard was only slightly attenuated by adjusting for sex and shared family factors [hazard ratio = 0.79, p = 0.002, 95% CI (0.68-0.92)].

Conclusions

Although somewhat conservative, adjusting for all variance shared by a family avoids any potential residual confounding of the intelligence-mortality association arising from the use of proxy measures of early-life SES. The present study demonstrates that the longevity associated with higher early-life intelligence cannot be explained by early-life SES or within-family factors.

Age and sex differences in intra-individual variability in a simple reaction time task

While age effects in reaction time (RT) tasks across the lifespan are well established for level of performance, analogous findings have started appearing also for indicators of intra-individual variability (IIV). Children are not only slower, but also display more variability than younger adults in RT. Yet, little is known about potential moderating sex effects on RT-IIV. We analyzed responses in a simple RT task with 120 trials in children, younger, and older adults. To best capture sex differences we used generalized additive models (GAMs), a semi-parametric regression approach, to fit splines relating nonlinearly age to RT, and capable of testing sex differences therein. This method is more adequate to test sex differences in nonlinear age relations than polynomial regression. Results show that (a) males are faster than females (except in the older adults), and (b) in younger and older adults, males are less variable than females. No sex difference in IIV emerged in children. Results are consistent with the hypothesis that sex differences in RT variability may be attributable to brain effects of sex hormones, in particular estrogen, whose receptors are present in several brain regions involved in information processing and attention, which are systems involved in the regulation of variability in information processing. Thus, according to this hypothesis, sex differences in RT-IIV should be present after puberty, but not in pre-pubertal children.

The Effect of a Pseudo Winning or Losing Streak on Mental Attitudes and the Evaluation of Results

Although human motivation has been well studied, studies manipulating human motivation are scarce. The present study aimed to induce the hot-hand phenomenon using a pseudo success situation. Under the framework of the two-factor theory of emotion, we investigated the effect of a deviant situation, such as continuously winning or losing, on mental attitudes and the evaluation of the results using the contingent-negative variation (CNV) and feedback-locked P3 (FB-P3). The CNV is a neural activity that reflects emotional expectations and motoric preparation. The FB-P3 is a neural activity that is induced by external feedback. Fifteen participants performed an S1-S2 reaction time task with an opponent in the following three competitive conditions: actual feedback (feedback is contingent on performance), winning streak (WS; tendency to win regardless of performance), and losing streak (LS; tendency to lose regardless of performance). Each condition was characterized by the winning rate (49.26%, 80%, and 20%). Moreover, a principal component analysis was performed on the CNV data to determine the distinct temporal neural activity. The principal component analysis identified three components (auditory P2, early CNV, and late CNV) in the original CNV. The auditory P2 and the occurrence of pleasant emotions were higher in the WS condition than in the LS condition. However, the early CNV, late CNV, and FB-P3 were higher in the LS condition than in the WS condition. These findings confirmed that the losing streak situation induced an unpleasant emotion. However, the losing streak situation appeared to improve the mental attitude to prepare for faster responses and enhance the interest in the results.

The Relationship Between the Score on a Simple Measure of Cognitive Function and Incident CVD in People With Diabetes: A Post Hoc Epidemiological Analysis From the ACCORD-MIND Study

CONTEXT AND OBJECTIVE

Diabetes is associated with a greater risk for incident cardiovascular disease and cognitive dysfunction. This study aimed to investigate, in people with type 2 diabetes, the association of a simple measure of cognitive function to cardiovascular disease events and mortality.

DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS, AND OUTCOMES

The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial included persons with longstanding type 2 diabetes. A substudy of 2977 (Memory in Diabetes) participants aged 55 years or older aimed to test the effect of the interventions on brain structure and function. At baseline, participants were administered a cognitive battery that included the digit symbol substitution test (DSST). The associations of the DSST and the ACCORD primary outcome (the first occurrence of nonfatal myocardial infarction or nonfatal stroke or death from cardiovascular causes) and all-cause mortality were investigated with Cox proportional hazard models adjusting for several demographic and clinical variables.

RESULTS

Median follow-up time was 4.27 years. An inverse relationship between the incidence of the ACCORD primary outcome and baseline cognitive score was demonstrated. A 1-point higher DSST score was associated with a lower incidence of the primary outcome (hazard ratio, 0.987; 95% confidence interval, 0.977 to 0.998; P = 0.019), after adjustment for demographic and clinical trial factors, additional baseline cardiovascular risk factors, and self-reported need for assistance to follow the protocol.

CONCLUSION

Lower scores on the DSST, a simple, sensitive neuropsychological instrument, are associated with a higher incidence of cardiovascular events in persons >55 years old with longstanding diabetes.

Is intraindividual reaction time variability an independent cognitive predictor of mortality in old age? Findings from the Sydney Memory and Ageing Study

Intraindividual variability of reaction time (IIV_RT), a proposed cognitive marker of neurobiological disturbance, increases in old age, and has been associated with dementia and mortality. The extent to which IIV_RT is an independent predictor of mortality, however, is unclear. This study investigated the association of IIV_RT and all-cause mortality while accounting for cognitive level, incident dementia and biomedical risk factors in 861 participants aged 70–90 from the Sydney Memory and Ageing Study. Participants completed two computerised reaction time (RT) tasks (76 trials in total) at baseline, and comprehensive medical and neuropsychological assessments every 2 years. Composite RT measures were derived from the two tasks—the mean RT and the IIV_RT measure computed from the intraindividual standard deviation of the RTs (with age and time-on-task effects partialled out). Consensus dementia diagnoses were made by an expert panel of clinicians using clinical criteria, and mortality data were obtained from a state registry. Cox proportional hazards models estimated the association of IIV_RT and mean RT with survival time over 8 years during which 191 (22.2%) participants died. Greater IIV_RT but not mean RT significantly predicted survival time after adjusting for age, sex, global cognition score, cardiovascular risk index and apolipoprotein ɛ4 status. After excluding incident dementia cases, the association of IIV_RT with mortality changed very little. Our findings suggest that greater IIV_RT uniquely predicts shorter time to death and that lower global cognition and prodromal dementia in older individuals do not explain this relationship.

Childhood IQ and survival to 79: Follow-up of 94% of the Scottish Mental Survey 1947

OBJECTIVE

To extend previous literature that suggests higher IQ in youth is associated with living longer. Previous studies have been unable to assess reliably whether the effect differs across sexes and ages of death, and whether the effect is graded across different levels of IQ.

METHODS

We test IQ-survival associations in 94% of the near-entire population born in Scotland in 1936 who took an IQ test at age 11 (n = 70,805) and were traced in a 68-year follow-up.

RESULTS

Higher IQ at age 11 years was associated with a lower risk of death (HR = 0.80, 95% CI = 0.79, 0.81). The decline in risk across categories of IQ scores was graded across the full range with the effect slightly stronger in women (HR = 0.79, 95% CI = 0.77, 0.80) than in men (HR = 0.82, 95% CI = 0.81, 0.84). Higher IQ had a significantly stronger association with death before and including age 65 (HR = 0.76, 95% CI = 0.74, 0.77) than in those participants who died at an older age (HR = 0.79, 95% CI = 0.78, 0.80).

CONCLUSIONS

Higher childhood IQ is associated with lower risk of all-cause mortality in both men and women. This is the only near-entire population study to date that examines the association between childhood IQ and mortality across most of the human life course.

A Systematic Review of Longitudinal Associations Between Reaction Time Intraindividual Variability and Age-Related Cognitive Decline or Impairment, Dementia, and Mortality

OBJECTIVES

Intraindividual variability (IIV) in reaction time refers to the trial-to-trial fluctuations in responding across a given cognitive task. Cross-sectional research suggests that IIV increases with normal and neuropathological ageing and it may serve as a marker of neurobiological integrity. This raises the possibility that IIV may also predict future cognitive decline and, indeed, neuropathology. Therefore, we conducted a systematic review to address these issues.

METHODS

A search of electronic databases Embase, Medline, PsycINFO, and Web of Science was completed on May 17, 2016 that identified longitudinal investigations of IIV in middle-aged or older adults.

RESULTS

A total of 688 studies were initially identified of which 22 met the inclusion criteria. Nine included longitudinal IIV measures and 17 predicted subsequent outcome (cognitive decline or impairment, dementia, mortality) from baseline IIV. The results suggested IIV increased over time, particularly in participants aged over 75 years. Greater baseline IIV was consistently associated with increased risk of adverse outcomes including cognitive decline or impairment, and mortality.

CONCLUSIONS

Increased IIV over time is associated with normal ageing. However, further increases in IIV over and above those found in normal ageing may be a risk factor for future cognitive impairment or mortality. Measures of IIV may, therefore, have considerable potential as a supplement to existing clinical assessment to aid identification of individuals at risk of adverse outcomes such as dementia or death. (JINS, 2017, 23, 431-445).

Do Cognitive and Physical Functions Age in Concert from Age 70 to 76? Evidence from the Lothian Birth Cohort 1936

The present study concerns the relation of mental and bodily characteristics to one another during ageing. The 'common cause' theory of ageing proposes that declines are shared across multiple, seemingly-disparate functions, including both physical and intellectual abilities. The concept of 'reserve' suggests that healthier cognitive (and perhaps bodily) functions from early in life are protective against the effects of senescence across multiple domains. In three waves of physical and cognitive testing data from the longitudinal Lothian Birth Cohort 1936 (n = 1,091 at age 70 years; n = 866 at 73; n = 697 at 76), we used multivariate growth curve modeling to test the 'common cause' and 'reserve' hypotheses. Support for both concepts was mixed: although levels of physical functions and cognitive functions were correlated with one another, physical functions did not decline together, and there was little evidence for shared declines in physical and mental functions. Early-life intelligence, a potential marker of system integrity, made a significant prediction of the levels, but not the slopes, of later life physical functions. These data suggest that common causes, which are likely present within cognitive functions, are not as far-reaching beyond the cognitive arena as has previously been suggested. They also imply that bodily reserve may be similar to cognitive reserve in that it affects the level, but not the slope, of ageing-related declines.

Verbal memory and search speed in early midlife are associated with mortality over 25 years' follow-up, independently of health status and early life factors: a British birth cohort study

BACKGROUND

Cognitive capabilities in childhood and in late life are inversely associated with mortality rates. However, it is unclear if adult cognition, at a time still relatively free from comorbidity, is associated with subsequent mortality, and whether this explains the associations of early life factors with adult mortality.

METHODS

We used data from the MRC National Survey of Health and Development, a birth cohort study prospectively assessing 5362 participants born in 1946. The present analysis includes participants followed up from age 43 and undergoing cognitive assessment (verbal memory and search speed). Mortality outcomes were notified through linkage with a national register. Cox regression was used to estimate mortality hazards in relation to cognitive performance at age 43, adjusting for early life factors, socioeconomic position and health status.

RESULTS

Data were available on 3192 individuals. Univariable analyses indicated that adult verbal memory and search speed, parental factors, childhood cognition and educational attainment were associated with mortality. However, multivariable models showed that the mortality associations with earlier life factors were explained by adult cognitive capability. A standard deviation increase in verbal memory and search speed scores was associated with lower mortality rates [hazard ratio (HR) = 0.86, 95% confidence interval (CI) 0.77-0.97, P = 0.02; HR = 0.88, 95% CI 0.78-1.00, P = 0.05, respectively), after adjustment for adult health.

CONCLUSIONS

Cognitive capability in early midlife was inversely associated with mortality rates over 25 years and accounted for the associations of family background, childhood cognitive ability and educational attainment with mortality. These findings, in a nationally representative cohort with long-term follow-up, suggest that building cognitive reserve may improve later life health and survival chances.

Genome-wide association study of cognitive functions and educational attainment in UK Biobank (N=112 151)

People's differences in cognitive functions are partly heritable and are associated with important life outcomes. Previous genome-wide association (GWA) studies of cognitive functions have found evidence for polygenic effects yet, to date, there are few replicated genetic associations. Here we use data from the UK Biobank sample to investigate the genetic contributions to variation in tests of three cognitive functions and in educational attainment. GWA analyses were performed for verbal-numerical reasoning (N=36 035), memory (N=112 067), reaction time (N=111 483) and for the attainment of a college or a university degree (N=111 114). We report genome-wide significant single-nucleotide polymorphism (SNP)-based associations in 20 genomic regions, and significant gene-based findings in 46 regions. These include findings in the ATXN2, CYP2DG, APBA1 and CADM2 genes. We report replication of these hits in published GWA studies of cognitive function, educational attainment and childhood intelligence. There is also replication, in UK Biobank, of SNP hits reported previously in GWA studies of educational attainment and cognitive function. GCTA-GREML analyses, using common SNPs (minor allele frequency>0.01), indicated significant SNP-based heritabilities of 31% (s.e.m.=1.8%) for verbal-numerical reasoning, 5% (s.e.m.=0.6%) for memory, 11% (s.e.m.=0.6%) for reaction time and 21% (s.e.m.=0.6%) for educational attainment. Polygenic score analyses indicate that up to 5% of the variance in cognitive test scores can be predicted in an independent cohort. The genomic regions identified include several novel loci, some of which have been associated with intracranial volume, neurodegeneration, Alzheimer's disease and schizophrenia.

Reaction time and onset of psychological distress: the UK Health and Lifestyle Survey

Background

Cross-sectional studies have shown that depression is often accompanied by less efficient cognitive function, as indicated by slower speed of information processing. The direction of effect is unclear. We investigated prospectively whether slower processing speed, as indexed by longer simple or choice reaction time, is associated with an increased risk of psychological distress.

Methods

Participants were 3088 men and women aged 18 and over who had taken part in the UK Health and Lifestyle Survey. Simple and choice reaction time was measured in the baseline survey. Symptoms of psychological distress were assessed at baseline and at the 7-year follow-up survey with the 30-item General Health Questionnaire (GHQ).

Results

In unadjusted models, a SD slower simple or choice reaction time at baseline was associated with ORs for psychological distress (≥5 on GHQ) at follow-up of 1.14 (1.06 to 1.23; p<0.001) or 1.13 (1.04 to 1.22; p=0.002), respectively. Further adjustment for age, sex, social class, educational attainment, health behaviours, number of chronic physical illnesses present, neuroticism and GHQ score at baseline had only slight attenuating effects on these associations. In fully adjusted models, a SD slower simple or choice reaction time at baseline was associated with ORs for psychological distress of 1.11 (1.02 to 1.21; p=0.017) or 1.11 (1.00 to 1.24; p=0.048), respectively.

Conclusions

Slower processing speed may be a risk factor for the development of psychological distress. Future studies should explore the extent to which slower processing speed explains previously demonstrated associations between lower intelligence and poorer mental health.

Association of Cognitive Function With Cause-Specific Mortality in Middle and Older Age: Follow-up of Participants in the English Longitudinal Study of Ageing

We examined the little-tested associations between general cognitive function in middle and older age and later risk of death from chronic diseases. In the English Longitudinal Study of Ageing (2002-2012), 11,391 study participants who were 50-100 years of age at study induction underwent a battery of cognitive tests and provided a range of collateral data. In an analytical sample of 9,204 people (4,982 women), there were 1,488 deaths during follow-up (mean duration, 9.0 years). When we combined scores from 4 cognition tests that represented 3 acknowledged key domains of cognitive functioning (memory, executive function, and processing speed), cognition was inversely associated with deaths from cancer (per each 1-standard-deviation decrease in general cognitive function score, hazard ratio = 1.21, 95% CI: 1.10, 1.33), cardiovascular disease (hazard ratio = 1.71, 95% CI: 1.55, 1.89), other causes (hazard ratio = 2.07, 95% CI: 1.79, 2.40), and respiratory illness (hazard ratio = 2.48, 95% CI: 2.12, 2.90). Controlling for a range of covariates, such as health behaviors and socioeconomic status, and left-censoring to explore reverse causality had very little impact on the strength of these relationships. These findings indicate that cognitive test scores can provide relatively simple indicators of the risk of death from an array of chronic diseases and that these associations appear to be independent of other commonly assessed risk factors.

Markers of Psychological Differences and Social and Health Inequalities: Possible Genetic and Phenotypic Overlaps

Associations between markers of ostensible psychological characteristics and social and health inequalities are pervasive but difficult to explain. In some cases, there may be causal influence flowing from social and health inequalities to psychological differences, whereas sometimes it may be the other way around. Here, we focus on the possibility that some markers that we often consider as indexing different domains of individual differences may in fact reflect at least partially overlapping genetic and/or phenotypic bases. For example, individual differences in cognitive abilities and educational attainment appear to reflect largely overlapping genetic influences, whereas cognitive abilities and health literacy may be almost identical phenomena at the phenotypic, never mind genetic, level. We make the case for employing molecular genetic data and quantitative genetic techniques to better understand the associations of psychological individual differences with social and health inequalities. We illustrate these arguments by using published findings from the Lothian Birth Cohort and the Generation Scotland studies. We also present novel findings pertaining to longitudinal stability and change in older age personality traits and some correlates of the change, molecular genetic data-based heritability estimates of Neuroticism and Extraversion, and the genetic correlations of these personality traits with markers of social and health inequalities.

Reaction time in adolescence, cumulative allostatic load, and symptoms of anxiety and depression in adulthood: the West of Scotland Twenty-07 Study

OBJECTIVE

To examine the relation between reaction time in adolescence and subsequent symptoms of anxiety and depression and investigate the mediating role of sociodemographic measures, health behaviors, and allostatic load.

METHODS

Participants were 705 members of the West of Scotland Twenty-07 Study. Choice reaction time was measured at age 16. At age 36 years, anxiety and depression were assessed with the 12-item General Health Questionnaire (GHQ) and the Hospital Anxiety and Depression Scale (HADS), and measurements were made of blood pressure, pulse rate, waist-to-hip ratio, and total and high-density lipoprotein cholesterol, C-reactive protein, albumin, and glycosolated hemoglobin from which allostatic load was calculated.

RESULTS

In unadjusted models, longer choice reaction time at age 16 years was positively associated with symptoms of anxiety and depression at age 36 years: for a standard deviation increment in choice reaction time, regression coefficients (95% confidence intervals) for logged GHQ score, and square-root-transformed HADS anxiety and depression scores were 0.048 (0.016-0.080), 0.064 (0.009-0.118), and 0.097 (0.032-0.163) respectively. Adjustment for sex, parental social class, GHQ score at age 16 years, health behaviors at age 36 years and allostatic load had little attenuating effect on the association between reaction time and GHQ score, but weakened those between reaction time and the HADS subscales. Part of the effect of reaction time on depression was mediated through allostatic load; this mediating role was of borderline significance after adjustment.

CONCLUSIONS

Adolescents with slower processing speed may be at increased risk for anxiety and depression. Cumulative allostatic load may partially mediate the relation between processing speed and depression.

More symmetrical children have faster and more consistent choice reaction times

Greater cognitive ability in childhood is associated with increased longevity, and speedier reaction time (RT) might account for much of this linkage. Greater bodily symmetry is linked to both higher cognitive test scores and faster RTs. It is possible, then, that differences in bodily system integrity indexed by symmetry may underlie the associations of RT and intelligence with increased longevity. However, RT and symmetry have seldom been examined in the same study, and never in children. Here, in 2 large samples aged 4 to 15 (combined n = 856), we found that more symmetrical children had significantly faster mean choice RT and less variability in RT. These associations of faster and less variable RT with greater symmetry early in life raise the possibility that the determinants of longevity in part originate in processes influencing bodily system integrity early in the life-course.

The smarter, the stronger: intelligence level correlates with brain resilience to systematic insults

Neuroimaging evidences posit human intelligence as tightly coupled with several structural and functional brain properties, also suggesting its potential protective role against aging and neurodegenerative conditions. However, whether higher order cognition might in fact lead to a more resilient brain has not been quantitatively demonstrated yet. Here we document a relationship between individual intelligence quotient (IQ) and brain resilience to targeted and random attacks, as measured through resting-state fMRI graph-theoretical analysis in 102 healthy individuals. In this modeling context, enhanced brain robustness to targeted attacks (TA) in individuals with higher IQ is supported by an increased distributed processing capacity despite the systematic loss of the most important node(s) of the system. Moreover, brain resilience in individuals with higher IQ is supported by a set of neocortical regions mainly belonging to language and memory processing network(s), whereas regions related to emotional processing are mostly responsible for lower IQ individuals. Results suggest intelligence level among the predictors of post-lesional or neurodegenerative recovery, also promoting the evolutionary role of higher order cognition, and simultaneously suggesting a new framework for brain stimulation interventions aimed at counteract brain deterioration over time.

Physical fitness is predictive for a decline in daily functioning in older adults with intellectual disabilities: results of the HA-ID study

A high incidence of limitations in daily functioning is seen in older adults with intellectual disabilities (ID), along with poor physical fitness levels. The aim of this study was to assess the predictive value of physical fitness for daily functioning after 3 years, in 602 older adults with borderline to profound ID (≥ 50 years). At baseline, physical fitness levels and daily functioning (operationalized as basic activities of daily living [ADL] and mobility) were assessed. After 3 years, the measurements of daily functioning were repeated. At follow-up, 12.6% of the participants were completely independent in ADL and 48.5% had no mobility limitations. More than half of the participants (54.8%) declined in their ability to perform ADL and 37.5% declined in their mobility. Manual dexterity, visual reaction time, balance, comfortable and fast gait speed, muscular endurance, and cardiorespiratory fitness were significant predictors for a decline in ADL. For a decline in mobility, manual dexterity, balance, comfortable and fast walking speed, grip strength, muscular endurance, and cardiorespiratory fitness were all significant predictors. This proves the predictive validity of these physical fitness tests for daily functioning and stresses the importance of using physical fitness tests and implementing physical fitness enhancing programs in the care for older adults with ID.

Cognitive impairment and cancer mortality: a biological or health care explanation?

PURPOSE

To examine whether the documented association of suboptimal cognitive function with total and cardiovascular (CVD) mortality also applies to cancer mortality and probe whether the explanation for this association is biomedical or health care related.

METHODS

In a subsample of 733 participants of the EPIC-Greece cohort from Athens and surrounding area, we assessed cognitive function at age 65 or older in the period 2004-2006, using the Mini-Mental State Examination (MMSE). Incidence of cancer, mortality from cancer and CVD, and overall mortality were ascertained through active follow-up for a median of 4 years after MMSE assessment using Cox proportional hazards models.

RESULTS

A total of 86 participants died during follow-up. A 2-point decrease in MMSE score was associated with increase in overall (hazard ratio (HR) 1.26, 95 % confidence interval (CI) 1.11-1.43), CVD (HR 1.26, 95 % CI 1.02-1.56), and cancer (HR 1.32, 95 % CI 1.02-1.70) mortality. In contrast, there was no noticeable difference in cancer incidence associated with a 2-point decrease in MMSE score (HR 1.07, 95 % CI 0.79-1.45).

CONCLUSIONS

Cognitive function appears to be inversely associated not only with CVD and overall, but also with cancer mortality. Although for CVD mortality there is a biomedical explanation invoking vascular mechanisms, for cancer mortality we may need to focus on socially conditioned factors, such as compromised ability to identify early signs and suboptimal compliance to treatment. Our hypothesis-generating results need to be confirmed in larger studies, as the issue is of major importance, since cognitive decline is not uncommon among the elderly.

Reaction time and incident cancer: 25 years of follow-up of study members in the UK Health and Lifestyle Survey

OBJECTIVES

To investigate the association of reaction time with cancer incidence.

METHODS

6900 individuals aged 18 to 94 years who participated in the UK Health and Lifestyle Survey in 1984/1985 and were followed for a cancer registration for 25 years.

RESULTS

Disease surveillance gave rise to 1015 cancer events from all sites. In general, there was essentially no clear pattern of association for either simple or choice reaction time with cancer of all sites combined, nor specific malignancies. However, selected associations were found for lung cancer, colorectal cancer and skin cancer.

CONCLUSIONS

In the present study, reaction time and its components were not generally related to cancer risk.

Subgroups associated with lower physical fitness in older adults with ID: results of the HA-ID study

Although physical fitness is generally very low in older adults with intellectual disabilities (ID), levels may differ across subgroups. It is important to identify which subgroups need to be targeted specifically in physical activity and fitness interventions and reference values. Physical fitness was measured with box-and-block-test, response-time-test, Berg-balance-scale, walking speed, grip strength, 30s-chair-stand, 10 m incremental-shuttle-walking test and the extended modified-back-saver-sit-and-reach-test in a large sample of older adults with ID (n=1050), and subgroups associated with lower physical fitness levels were identified applying multivariate linear regression analyses. Both fixed personal characteristics such as being older, being female, having more severe ID and having Down syndrome and modifiable or preventable factors such as physical activity levels, mobility impairments and a need of more intensive care, are independently associated with lower levels of multiple physical fitness components. This first study identifies subgroups of older adults with ID which require adapted reference values, and subgroups that need to be specifically targeted in fitness promotion programs.

Reaction time and mortality from the major causes of death: the NHANES-III study

OBJECTIVE

Studies examining the relation of information processing speed, as measured by reaction time, with mortality are scarce. We explored these associations in a representative sample of the US population.

METHODS

Participants were 5,134 adults (2,342 men) aged 20-59 years from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-94).

RESULTS

Adjusted for age, sex, and ethnic minority status, a 1 SD slower reaction time was associated with a raised risk of mortality from all-causes (HR = 1.25, 95% CI 1.12, 1.39) and cardiovascular disease (CVD) (HR = 1.36, 95% CI 1.17, 1.58). Having 1 SD more variable reaction time was also associated with greater risk of all-cause (HR = 1.36, 95% CI 1.19, 1.55) and CVD (HR = 1.50, 95% CI 1.33, 1.70) mortality. No associations were observed for cancer mortality. The magnitude of the relationships was comparable in size to established risk factors in this dataset, such as smoking.

INTERPRETATION

Alongside better-established risk factors, reaction time is associated with increased risk of premature death and cardiovascular disease. It is a candidate risk factor for all-cause and cause-specific mortality.

Intra-individual reaction time variability and all-cause mortality over 17 years: a community-based cohort study

BACKGROUND

very few studies have examined the association between intra-individual reaction time variability and subsequent mortality. Furthermore, the ability of simple measures of variability to predict mortality has not been compared with more complex measures.

METHOD

a prospective cohort study of 896 community-based Australian adults aged 70+ were interviewed up to four times from 1990 to 2002, with vital status assessed until June 2007. From this cohort, 770-790 participants were included in Cox proportional hazards regression models of survival. Vital status and time in study were used to conduct survival analyses. The mean reaction time and three measures of intra-individual reaction time variability were calculated separately across 20 trials of simple and choice reaction time tasks. Models were adjusted for a range of demographic, physical health and mental health measures.

RESULTS

greater intra-individual simple reaction time variability, as assessed by the raw standard deviation (raw SD), coefficient of variation (CV) or the intra-individual standard deviation (ISD), was strongly associated with an increased hazard of all-cause mortality in adjusted Cox regression models. The mean reaction time had no significant association with mortality.

CONCLUSION

intra-individual variability in simple reaction time appears to have a robust association with mortality over 17 years. Health professionals such as neuropsychologists may benefit in their detection of neuropathology by supplementing neuropsychiatric testing with the straightforward process of testing simple reaction time and calculating raw SD or CV.

New light for old eyes: comparing melanopsin-mediated non-visual benefits of blue-light and UV-blocking intraocular lenses

BACKGROUND/AIMS

Melanopsin-expressing photosensitive retinal ganglion cells form a blue-light-sensitive non-visual system mediating diverse physiological effects including circadian entrainment and cognitive alertness. Reduced blue wavelength retinal illumination through cataract formation is thought to blunt these responses while cataract surgery and intraocular lens (IOL) implantation have been shown to have beneficial effects on sleep and cognition. We aimed to use the reaction time (RT) task and the Epworth Sleepiness Score (ESS) as a validated objective platform to compare non-visual benefits of UV- and blue-blocking IOLs.

METHODS

Patients were prospectively randomised to receive either a UV- or blue-blocking IOL, performing an RT test and ESS questionnaire before and after surgery. Optical blurring at the second test controlled for visual improvement. Non-operative age-matched controls were recruited for comparison.

RESULTS

80 participants completed the study. Those undergoing first-eye phacoemulsification demonstrated significant improvements in RT over control (p=0.001) and second-eye surgery patients (p=0.03). Moreover, reduced daytime sleepiness was measured by ESS for the first-eye surgery group (p=0.008) but not for the second-eye group (p=0.09). Choice of UV- or blue-blocking IOL made no significant difference to magnitude of cognitive improvement (p=0.272).

CONCLUSIONS

Phacoemulsification, particularly first-eye surgery, has a strong positive effect on cognition and daytime alertness, regardless of IOL type.

Cognitive and personality factors in the prediction of health behaviors: an examination of total, direct and indirect effects

Conscientiousness reliably predicts health behavioral patterns, and the same is true of executive function. However, few investigations have examined their relative predictive power, or probed for possible indirect effects and age-moderated effects. In the current study, we examined the predictive validity of all Big Five personality traits, executive function and IQ in relation to an index of health behaviors in an age-stratified community sample. Results indicated that conscientiousness, neuroticism and executive function were significant predictors of health behavior in age-corrected regression analyses. Using bootstrapping methods, we found that executive function partially explains the relationship between both personality dimensions and health behavior. Moderational analyses revealed that effects of personality traits on health behavior were uniformly modest across the age span, whereas the predictive power of executive function became more amplified with increasing age. Both conscientiousness and neuroticism predict health behavior patterns, though their magnitude of association is significantly weaker than executive function and some of their effects are explained by executive function.