Childhood IQ in relation to risk factors for premature mortality in middle-aged persons: the Aberdeen Children of the 1950s study

Cognitive function in adolescence and the risk of early-onset stroke

BACKGROUND

Stroke is increasingly prevalent at younger ages but the risk factors are uncertain. We examined the association between adolescent cognitive function and early-onset stroke.

METHODS

This was a nationwide population-based cohort study of 1 741 345 Israeli adolescents (42% women) who underwent comprehensive cognitive function tests at age 16-20 years, before mandatory military service, during 1987-2012. Cognitive function (range: 1-9) was categorised as low (1-3, corresponding to IQ score below 89), medium (4-7, IQ score range: 89-118), or high (8-9, IQ score above 118). Participant data were linked to the Israeli National Stroke Registry. Cox proportional hazard models were used to estimate risks for the first occurrence of ischaemic stroke during 2014-2018.

RESULTS

During 8 689 329 person-years of follow-up, up to a maximum age of 50 years, 908 first stroke events occurred (767 ischaemic and 141 haemorrhagic). Compared with a reference group of people with high cognitive function, body mass index-adjusted and sociodemographic-adjusted HRs (95% CIs) for early-onset stroke were 1.78 (1.33-2.38) in medium and 2.68 (1.96-3.67) in low cognitive function groups. There was evidence of a dose-response relationship (P for trend <0.0001) such that one-unit of lower cognitive function z-score was associated with a 33% increased risk of stroke (1.33; 1.23-1.42). These associations were similar for ischaemic stroke but lower for haemorrhagic stroke; persisted in sensitivity analyses that accounted for diabetes status and hypertension; and were evident before age 40 years.

CONCLUSIONS

Alongside adolescent obesity and hypertension, lower cognitive function may be a risk factor for early-onset stroke.

The Social and Emotional Education and Development intervention to address wellbeing in primary school age children: the SEED cluster RCT

Background

Stronger social and emotional well-being during primary school is positively associated with the health and educational outcomes of young people. However, there is little evidence on which programmes are the most effective for improving social and emotional well-being.

Objective

The objective was to rigorously evaluate the Social and Emotional Education and Development (SEED) intervention process for improving pupils' social and emotional well-being.

Design

This was a stratified cluster randomised controlled trial with embedded process and economic evaluations. Thirty-eight primary schools were randomly assigned to the SEED intervention or to the control group. Hierarchical regression analysis allowing for clustering at school learning community level was conducted in R (statistical package).

Setting

The SEED intervention is a whole-school intervention; it involved all school staff and two cohorts of pupils, one starting at 4 or 5 years of age and the second starting at 8 or 9 years of age, across all 38 schools.

Participants

A total of 2639 pupils in Scotland.

Intervention

The SEED intervention used an iterative process that involved three components to facilitate selection and implementation of school-based actions: (1) questionnaire completion, (2) benchmarked feedback to all staff and (3) reflective discussions (all staff and an educational psychologist).

Main outcome measure

The primary outcome was pupils' Strengths and Difficulties Questionnaire-Total Difficulties Score when pupils were 4 years older than at baseline.

Results

The primary outcome, pupils' Strengths and Difficulties Questionnaire-Total Difficulties Score at follow-up 3, showed improvements for intervention arm pupils, compared with those in the control arm [relative risk -1.30 (95% confidence interval -1.87 to -0.73), standardised effect size -0.27 (95% confidence interval -0.39 to -0.15)]. There was no evidence of intervention effects according to deprivation: the results were significant for both affluent and deprived pupils. Subgroup analysis showed that all effect sizes were larger for the older cohort, particularly boys [relative risk -2.36 (95% confidence interval -3.62 to -1.11), standardised effect size -0.42 (95% confidence interval -0.64 to -0.20)]. Although there was no statistically significant difference in incremental cost and quality-adjusted life-years, the probability that the intervention is cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life-year was high, at 88%. Particularly valued mechanisms of the SEED intervention were its provision of time to reflect on and discuss social and emotional well-being and its contribution to a culture of evaluating practice.

Limitations

It was a challenge to retain schools over five waves of data collection.

Conclusions

This trial demonstrated that the SEED intervention is an acceptable, cost-effective way to modestly improve pupil well-being and improve school climate, particularly for older boys and those with greater levels of psychological difficulties. It was beneficial during the transition from primary to secondary school, but this diminished after 6 years. The SEED intervention can be implemented alongside existing systems for addressing pupil well-being and can be complementary to other interventions.

Future work

Assess whether or not the SEED intervention has a beneficial impact on academic attainment, is transferable to other countries and other organisational settings, would be strengthened by adding core training elements to the intervention process and is transferable to secondary schools. Understand the gender differences illustrated by the outcomes of this trial. Conduct further statistical research on how to handle missing data in longitudinal studies of complex social interventions.

Trial registration

This trial is registered as ISRCTN51707384.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme (NIHR award ref: 10/3006/13) and is published in full in Public Health Research; Vol. 12, No. 6. See the NIHR Funding and Awards website for further award information.

IQ in high school as a predictor of midlife alcohol drinking patterns

AIMS

The aim of the present study was to assess the relationship between adolescent IQ and midlife alcohol use and to explore possible mediators of this relationship.

METHODS

Study data were from 6300 men and women who participated in the Wisconsin Longitudinal Study of high-school students graduating in 1957. IQ scores were collected during the participants' junior year of high school. In 2004, participants reported the number of alcoholic beverages consumed (past 30 days) and the number of binge-drinking episodes. A multinomial logistic regression was conducted to determine the relationship between adolescent IQ and future drinking pattern (abstainer, moderate drinker, or heavy drinker), and Poisson regression was used to examine the number of binge-drinking episodes. Two mediators-income and education-were also explored.

RESULTS

Every one-point increase in IQ score was associated with a 1.6% increase in the likelihood of reporting moderate or heavy drinking as compared to abstinence. Those with higher IQ scores also had significantly fewer binge-drinking episodes. Household income, but not education, partially mediated the relationship between IQ and drinking pattern.

CONCLUSIONS

The present study suggests that higher adolescent IQ may predict a higher likelihood of moderate or heavy drinking in midlife, but fewer binge-drinking episodes. The study also suggests that this relationship is mediated by other psychosocial factors, specifically income, prompting future exploration of mediators in subsequent studies.

Repetitive thought, cognition, and systemic inflammation in the midlife in the United States study

OBJECTIVE

Poor cognition increases risk for negative health outcomes, and this may be explained by associations with systemic inflammation. Previously, amount of repetitive thought (Total RT) interacted with IQ to predict interleukin-6 (IL-6) in older adults. This study continued the investigation of repetitive thought (RT) as an element involved in the effect of cognition on inflammation.

DESIGN

Participants (N = 164) came from the Midlife in the United States Refresher project (Mage = 45.33, SD = 11.51, ranges = 25-74; 48.2% female; 85% Caucasian). Cognition was assessed via telephone, inflammatory biomarkers (IL-6, C-reactive protein (CRP), and tumour-necrosis factor-alpha (TNF- α)) analysed after blood draw, and RT derived from daily diary data.

RESULTS

Cognition significantly interacted with RT valence (p = .009) to explain CRP after covariate adjustment. Better cognition and more negative RT valence was associated with lower CRP (β = -0.190 [-.387, .008]). Worse cognition and more negative RT valence was associated with higher CRP (β = 0.133 [-.031, .297]). No significant effects were found for IL-6 or TNF-α.

CONCLUSION

RT may interact with cognition to affect different inflammatory biomarkers. Those with worse cognition may benefit more from skills related to regulating thought than those with better cognition.

The association between cognitive ability and body mass index: A sibling-comparison analysis in four longitudinal studies

BACKGROUND

Body mass index (BMI) and obesity rates have increased sharply since the 1980s. While multiple epidemiologic studies have found that higher adolescent cognitive ability is associated with lower adult BMI, residual and unobserved confounding due to family background may explain these associations. We used a sibling design to test this association accounting for confounding factors shared within households.

METHODS AND FINDINGS

We used data from four United States general youth population cohort studies: the National Longitudinal Study of Youth 1979 (NLSY-79), the NLSY-79 Children and Young Adult, the NLSY 1997 (NLSY-97), and the Wisconsin Longitudinal Study (WLS); a total of 12,250 siblings from 5,602 households followed from adolescence up to age 62. We used random effects within-between (REWB) and residualized quantile regression (RQR) models to compare between- and within-family estimates of the association between adolescent cognitive ability and adult BMI (20 to 64 years). In REWB models, moving from the 25th to 75th percentile of adolescent cognitive ability was associated with -0.95 kg/m2 (95% CI = -1.21, -0.69) lower BMI between families. Adjusting for family socioeconomic position reduced the association to -0.61 kg/m2 (-0.90, -0.33). However, within families, the association was just -0.06 kg/m2 (-0.35, 0.23). This pattern of results was found across multiple specifications, including analyses conducted in separate cohorts, models examining age-differences in association, and in RQR models examining the association across the distribution of BMI. Limitations include the possibility that within-family estimates are biased due to measurement error of the exposure, confounding via non-shared factors, and carryover effects.

CONCLUSIONS

The association between high adolescent cognitive ability and low adult BMI was substantially smaller in within-family compared with between-family analysis. The well-replicated associations between cognitive ability and subsequent BMI may largely reflect confounding by family background factors.

High Morphine Use Disorder Susceptibility Is Predicted by Impaired Learning Ability in Mice

An obvious reason for substance uses disorders (SUDs) is drug craving and seeking behavior induced by conditioned context, which is an abnormal solid context memory. The relationship between susceptibility to SUD and learning ability remains unclear in humans and animal models. In this study, we found that susceptibility to morphine use disorder (MUD) was negatively correlated with learning ability in conditioned place preference (CPP) in C57 mice. By using behavioral tests, we identified the FVB mouse as learning impaired. In addition, we discovered that learning-relevant proteins, such as the glutamate receptor subunits GluA1, NR1, and NR2A, were decreased in FVB mice. Finally, we assessed the context learning ability of FVB mice using the CPP test and priming. We found that FVB mice had lower learning performance with respect to normal memory but higher performance of morphine-reinstatement memory. Compared to C57 mice, FVB mice are highly sensitive to MUDs. Our results suggest that SUD susceptibility is predicted by impaired learning ability in mice; therefore, learning ability can play a simple and practical role in identifying high-risk SUD groups.

Association of functional health literacy and cognitive ability with self-reported diabetes in the English Longitudinal Study of Ageing: a prospective cohort study

OBJECTIVES

We investigated whether functional health literacy and cognitive ability were associated with self-reported diabetes.

DESIGN

Prospective cohort study.

SETTING

Data were from waves 2 (2004-2005) to 7 (2014-2015) of the English Longitudinal Study of Ageing (ELSA), a cohort study designed to be representative of adults aged 50 years and older living in England.

PARTICIPANTS

8669 ELSA participants (mean age=66.7, SD=9.7) who completed a brief functional health literacy test assessing health-related reading comprehension, and 4 cognitive tests assessing declarative memory, processing speed and executive function at wave 2.

PRIMARY OUTCOME MEASURE

Self-reported doctor diagnosis of diabetes.

RESULTS

Logistic regression was used to examine cross-sectional (wave 2) associations of functional health literacy and cognitive ability with diabetes status. Adequate (compared with limited) functional health literacy (OR 0.71, 95% CI 0.61 to 0.84) and higher cognitive ability (OR per 1 SD=0.73, 95% CI 0.67 to 0.80) were associated with lower odds of self-reporting diabetes at wave 2. Cox regression was used to test the associations of functional health literacy and cognitive ability measured at wave 2 with self-reporting diabetes over a median of 9.5 years follow-up (n=6961). Adequate functional health literacy (HR 0.64; 95% CI 0.53 to 0.77) and higher cognitive ability (HR 0.77, 95% CI 0.69 to 0.85) at wave 2 were associated with lower risk of self-reporting diabetes during follow-up. When both functional health literacy and cognitive ability were added to the same model, these associations were slightly attenuated. Additionally adjusting for health behaviours and body mass index fully attenuated cross-sectional associations between functional health literacy and cognitive ability with diabetes status, and partly attenuated associations between functional health literacy and cognitive ability with self-reporting diabetes during follow-up.

CONCLUSIONS

Adequate functional health literacy and better cognitive ability were independently associated with lower likelihood of reporting diabetes.

Pre-pandemic cognitive function and COVID-19 vaccine hesitancy: cohort study

BACKGROUND

Whereas several predictors of COVID-19 vaccine hesitancy have been reported, the role of cognitive function is largely unknown. Accordingly, our objective was to evaluate the association between scores from an array of cognitive function tests and self-reported vaccine hesitancy after the announcement of the successful testing of the first COVID-19 vaccine (Oxford University/AstraZeneca).

METHODS

We used individual-level data from a pandemic-focused study ('COVID Survey'), a prospective cohort study nested within United Kingdom Understanding Society ('Main Survey'). In the week immediately following the announcement of successful testing of the first efficacious inoculation (November/December 2020), data on vaccine intentionality were collected in 11,740 individuals (6702 women) aged 16-95 years. Pre-pandemic scores on general cognitive function, ascertained from a battery of six tests, were captured in 2011/12 wave of the Main Survey. Study members self-reported their intention to take up a vaccination in the COVID-19 Survey.

RESULTS

Of the study sample, 17.2% (N = 1842) indicated they were hesitant about having the vaccine. After adjustment for age, sex, and ethnicity, study members with a lower baseline cognition score were markedly more likely to be vaccine hesitant (odds ratio per standard deviation lower score in cognition; 95% confidence interval: 1.76; 1.62, 1.90). Adjustment for mental and physical health plus household shielding status had no impact on these results, whereas controlling for educational attainment led to partial attenuation but the probability of hesitancy was still elevated (1.52; 1.37, 1.67). There was a linear association for vaccine hesitancy across the full range of cognition scores (p for trend: p < 0.0001).

CONCLUSIONS

Erroneous social media reports might have complicated personal decision-making, leading to people with lower cognitive ability being vaccine-hesitant. With individuals with lower cognition also experiencing higher rates of COVID-19 in studies conducted prior to vaccine distribution, these new findings are suggestive of a potential additional disease burden.

The Edinburgh Lifetime Musical Experience Questionnaire (ELMEQ): Responses and non-musical correlates in the Lothian Birth Cohort 1936

There is growing evidence of the potential effects of musical training on the human brain, as well as increasing interest in the potential contribution of musical experience to healthy ageing. Conducting research on these topics with older adults requires a comprehensive assessment of musical experience across the lifespan, as well as an understanding of which variables might correlate with musical training and experience (such as personality traits or years of education). The present study introduces a short questionnaire for assessing lifetime musical training and experience in older populations: the Edinburgh Lifetime Musical Experience Questionnaire (ELMEQ). 420 participants from the Lothian Birth Cohort 1936 completed the ELMEQ at a mean age of 82 years. We used their responses to the ELMEQ to address three objectives: 1) to report the prevalence of lifetime musical experience in a sample of older adults; 2) to demonstrate how certain item-level responses can be used to model latent variables quantifying experience in different musical domains (playing a musical instrument, singing, self-reported musical ability, and music listening); and 3) to examine non-musical (lifespan) correlates of these domains. In this cohort, 420 of 431 participants (97%) completed the questionnaire. 40% of participants reported some lifetime experience of playing a musical instrument, starting at a median age of 10 years and playing for a median of 5 years. 38% of participants reported some lifetime experience of singing in a group. Non-musical variables of childhood environment, years of education, childhood cognitive ability, female sex, extraversion, history of arthritis and fewer constraints on activities of daily living were found to be associated, variously, with the domains of playing a musical instrument, singing, self-reported musical ability, and music listening. The ELMEQ was found to be an effective research tool with older adults and is made freely available for future research.

Disrupted parahippocampal and midbrain function underlie slower verbal learning in adolescent-onset regular cannabis use

RATIONALE

Prolonged use of cannabis, the most widely used illicit drug worldwide, has been consistently associated with impairment in memory and verbal learning. Although the neurophysiological underpinnings of these impairments have been investigated previously using functional magnetic resonance imaging (fMRI), while performing memory tasks, the results of these studies have been inconsistent and no clear picture has emerged yet. Furthermore, no previous studies have investigated trial-by-trial learning.

OBJECTIVES

We aimed to investigate the neural underpinnings of impaired verbal learning in cannabis users as estimated over repeated learning trials.

METHODS

We studied 21 adolescent-onset regular cannabis users and 21 non-users using fMRI performed at least 12 h after last cannabis use, while they performed a paired associate verbal learning task that allowed us to examine trial-by-trial learning. Brain activation during repeated verbal encoding and recall conditions of the task was indexed using the blood oxygen level-dependent haemodynamic response fMRI signal.

RESULTS

There was a significant improvement in recall score over repeated trials indicating learning occurring across the two groups of participants. However, learning was significantly slower in cannabis users compared to non-users (p = 0.032, partial eta-squared = 0.108). While learning verbal stimuli over repeated encoding blocks, non-users displayed progressive increase in recruitment of the midbrain, parahippocampal gyrus and thalamus (p = 0.00939, partial eta-squared = 0.180). In contrast, cannabis users displayed a greater but disrupted activation pattern in these regions, which showed a stronger correlation with new word-pairs learnt over the same blocks in cannabis users than in non-users.

CONCLUSIONS

These results suggest that disrupted medial temporal and midbrain function underlie slower learning in adolescent-onset cannabis users.

Pre-pandemic cognitive function and COVID-19 mortality: prospective cohort study

Poorer performance on standard tests of pre-morbid cognitive function is related to an elevated risk of death from lower respiratory tract infections but the link with coronavirus (COVID‑19) mortality is untested. Participants in UK Biobank, aged 40 to 69 years at study induction (2006-10), were administered a reaction time test, an indicator of information processing speed, and also had their verbal-numeric reasoning assessed. Between April 1st and September 23rd 2020 there were 388 registry-confirmed deaths (138 women) ascribed to COVID-19 in 494,932 individuals (269,602 women) with a reaction time test result, and 125 such deaths (38 women) in the subgroup of 180,198 people (97,794 women) with data on verbal-numeric reasoning. In analyses adjusted for age, sex, and ethnicity, a one standard deviation slower reaction time was related to a higher rate of death from COVID-19 (hazard ratio; 95% confidence interval: 1.18; 1.09, 1.28), as was a one standard deviation disadvantage on the verbal-numeric reasoning test (1.32; 1.09, 1.59). While there was some attenuation in these relationships after adjustment for additional covariates which included socio-economic status and lifestyle factors, the two pre-pandemic indicators of cognitive function continued to be related to COVID-19 mortality.

Intelligence, health and death

The field of cognitive epidemiology studies the prospective associations between cognitive abilities and health outcomes. We review research in this field over the past decade and describe how our understanding of the association between intelligence and all-cause mortality has consolidated with the appearance of new, population-scale data. To try to understand the association better, we discuss how intelligence relates to specific causes of death, diseases/diagnoses and biomarkers of health through the adult life course. We examine the extent to which mortality and health associations with intelligence might be attributable to people's differences in education, other indicators of socioeconomic status, health literacy and adult environments and behaviours. Finally, we discuss whether genetic data provide new tools to understand parts of the intelligence-health associations. Social epidemiologists, differential psychologists and behavioural and statistical geneticists, among others, contribute to cognitive epidemiology; advances will occur by building on a common cross-disciplinary knowledge base.

Pre-pandemic Cognitive Function and COVID-19 Vaccine Hesitancy: Cohort Study

Background

Whereas several predictors of COVID-19 vaccine hesitancy have been examined, the role of cognitive function following the widely publicised development of an inoculation is unknown.

Objective

To test the association between scores from an array of cognitive function tests and self-reported vaccine hesitancy after the announcement of the successful testing of the Oxford University/AstraZeneca vaccine.

Design Setting and Participants

We used individual-level data from a pandemic-focused study (COVID Survey), a prospective cohort study nested within Understanding Society (Main Survey). In the week immediately following the announcement of successful testing of the first efficacious inoculation (November/December 2020), data on vaccine intentionality were collected in 11740 individuals (6702 women) aged 16-95. Pre-pandemic scores on general cognitive function, ascertained from a battery of six tests, were captured in 2011/12 wave of the Main Survey.

Measurements

Self-reported intention to take up a vaccination for COVID-19. To summarise our results, we computed odds ratios with accompanying 95% confidence intervals for general cognitive function adjusted for selected covariates.

Results

Of the study sample, 17.2% (N=1842) indicated they were hesitant about having the vaccine. After adjustment for age, sex, and ethnicity, study members with a lower baseline cognition score were markedly more likely to be vaccine hesitant (odds ratio per standard deviation lower score in cognition; 95% confidence interval: 1.76; 1.62, 1.90). Adjustment for mental and physical health plus household shielding status had no impact on these results, whereas controlling for educational attainment led to partial attenuation but the probability of hesitancy was still elevated (1.52; 1.37, 1.67). There was a linear association for vaccine hesitancy across the full range of cognition scores (p for trend: p<0.0001).

Limitations

Our outcome was based on intention rather than behaviour.

Conclusions

Erroneous social media reports might have complicated personal decision-making, leading to people with lower cognitive ability test scores being vaccine-hesitant. With people with lower cognition also experiencing higher rates of COVID-19 in studies conducted prior to vaccine distribution, these new findings are suggestive of a potential additional disease burden.

Pre-pandemic cognitive function and COVID-19 mortality: prospective cohort study

Background

Poorer performance on standard tests of cognitive function is related to an elevated risk of death from lower respiratory tract infections. Whether pre-pandemic measures of cognition are related to COVID-19 mortality is untested.

Methods

UK Biobank, a prospective cohort study, comprises around half a million people who were aged 40 to 69 years at study induction between 2006 and 2010 when a reaction time test was administered to the full sample, and verbal-numeric reasoning assessed in a subgroup. Death from COVID-19 was ascertained from participant linkage to a UK-wide national registry.

Results

Between April 1st and September 23rd 2020, there were 388 deaths (138 women) ascribed to COVID-19 in the 494,932 individuals (269,602 women) with a reaction time test result, and 125 such deaths (38 women) in the 180,198 (97,794 women) for whom there were data on verbal-numeric reasoning. In analyses adjusted for age, sex, and ethnicity, a one standard deviation (118.2 msec) slower reaction time was related to a higher rate of death from COVID-19 (hazard ratio; 95% confidence interval: 1.18; 1.09, 1.28). A one standard deviation disadvantage (2.16 point) on the verbal-numeric reasoning test was also associated with an elevated risk of death (1.32; 1.09, 1.59). Attenuation after adjustment for additional covariates followed a similar pattern for both measures of cognition. For verbal-numeric reasoning, for instance, the hazard ratios were 1.22 (0.98, 1.51) after control for socioeconomic status, 1.16 (0.96, 1.41) after lifestyle factors, 1.25 (1.04, 1.52) after co-morbidity, and 1.29 (1.01, 1.64) after physiological indices.

Conclusions

In the present study, poorer performance on two pre-pandemic indicators of cognitive function, including reaction time, a knowledge-reduced measure, was related to death ascribed to COVID-19.

Associations Between Hearing and Cognitive Abilities From Childhood to Middle Age: The National Child Development Study 1958

Previous cross-sectional findings indicate that hearing and cognitive abilities are positively correlated in childhood, adulthood, and older age. We used an unusually valuable longitudinal dataset from a single-year birth cohort study, the National Child Development Study 1958, to test how hearing and cognitive abilities relate to one another across the life course from childhood to middle age. Cognitive ability was assessed with a single test of general cognitive ability at age 11 years and again with multiple tests at age 50. Hearing ability was assessed, using a pure tone audiogram, in childhood at ages 11 and 16 and again at age 44. Associations between childhood and middle-age hearing and cognitive abilities were investigated using structural equation modelling. We found that higher cognitive ability was associated with better hearing (indicated by a lower score on the hearing ability variables); this association was apparent in childhood (r  =  -0.120, p <0.001) and middle age (r  =  -0.208, p <0.001). There was a reciprocal relationship between hearing and cognitive abilities over time: better hearing in childhood was weakly associated with a higher cognitive ability in middle age (β  =  -0.076, p  =  0.001), and a higher cognitive ability in childhood was associated with better hearing in middle age (β  =  -0.163, p <0.001). This latter, stronger effect was mediated by occupational and health variables in adulthood. Our results point to the discovery of a potentially life-long relationship between hearing and cognitive abilities and demonstrate how these variables may influence one another over time.

Educational differences in labor market marginalization among mature-aged working men: the contribution of early health behaviors, previous employment histories, and poor mental health

BACKGROUND

Social inequalities in labor force participation are well established, but the causes of these inequalities are not fully understood. The present study aims to investigate the association between educational qualification and labor market marginalization (LMM) among mature-aged working men and to examine to what extent the association can be explained by risk factors over the life course.

METHOD

The study was based on a cohort of men born between 1949 and 1951 who were examined for Swedish military service in 1969/70 and employed in 2000 (n = 41,685). Data on educational qualification was obtained in 2000 and information on the outcome of LMM (unemployment, sickness absence, and disability pension) was obtained between 2001 and 2008. Information on early health behaviors, cognitive ability, previous employment histories, and mental health was collected from conscription examinations and nationwide registers.

RESULTS

Evidence of a graded association between years of education and LMM was found. In the crude model, compared to men with the highest level of education men with less than 12 years of schooling had more than a 2.5-fold increased risk of health-related LMM and more than a 1.5-fold increased risk of non-health-related LMM. Risk factors measured across the life course explained a large part of the association between education and health-related LMM (33-61%) and non-health-related LMM (13-58%).

CONCLUSIONS

Educational differences remained regarding LMM among mature-aged workers, even after considering several important risk factors measured across the life course. Previous health problems and disrupted employment histories explained the largest part of the associations.

Psychosocial factors and hospitalisations for COVID-19: Prospective cohort study based on a community sample

BACKGROUND

While certain infectious diseases have been linked to socioeconomic disadvantage, mental health problems, and lower cognitive function, relationships with COVID-19 are either uncertain or untested. Our objective was to examine the association of a range of psychosocial factors with hospitalisation for COVID-19.

METHODS

UK Biobank, a prospective cohort study, comprises around half a million people who were aged 40-69 years at study induction between 2006 and 2010 when information on psychosocial factors and covariates were captured. Hospitalisations for COVID-19 were ascertained between 16th March and 26th April 2020.

RESULTS

There were 908 hospitalisations for COVID-19 in an analytical sample of 431,051 England-based study members. In age- and sex-adjusted analyses, an elevated risk of COVID-19 was related to disadvantaged levels of education (odds ratio; 95% confidence interval: 2.05; 1.70, 2.47), income (2.00; 1.63, 2,47), area deprivation (2.20; 1.86, 2.59), occupation (1.39; 1.14, 1.69), psychological distress (1.58; 1.32, 1.89), mental health (1.50; 1.25, 1.79), neuroticism (1.19; 1.00, 1.42), and performance on two tests of cognitive function - verbal and numerical reasoning (2.66; 2.06, 3.34) and reaction speed (1.27; 1.08, 1.51). These associations were graded (p-value for trend ≤ 0.038) such that effects were apparent across the full psychosocial continua. After mutual adjustment for these characteristics plus ethnicity, comorbidity, and lifestyle factors, only the relationship between lower cognitive function as measured using the reasoning test and risk of the infection remained (1.98; 1.38, 2.85).

CONCLUSIONS

A range of psychosocial factors revealed associations with hospitalisation for COVID-19 of which the relation with cognitive function, a marker of health literacy, was most robust.

Adolescent Substance Use and the Brain: Behavioral, Cognitive and Neuroimaging Correlates

Adolescence is an important ontogenetic period that is characterized by behaviors such as enhanced novelty-seeking, impulsivity, and reward preference, which can give rise to an increased risk for substance use. While substance use rates in adolescence are generally on a decline, the current rates combined with emerging trends, such as increases in e-cigarette use, remain a significant public health concern. In this review, we focus on the neurobiological divergences associated with adolescent substance use, derived from a cross-sectional, retrospective, and longitudinal studies, and highlight how the use of these substances during adolescence may relate to behavioral and neuroimaging-based outcomes. Identifying and understanding the associations between adolescent substance use and changes in cognition, mental health, and future substance use risk may assist our understanding of the consequences of drug exposure during this critical window.

The long arm of childhood intelligence on terminal decline: Evidence from the Lothian Birth Cohort 1921

The current study investigates the heterogeneity of cognitive trajectories at the end of life by assigning individuals into groups according to their cognitive trajectories prior to death. It also examines the role of childhood intelligence and education on these trajectories and group membership. Participants were drawn from the Lothian Birth Cohort of 1921 (LBC1921), a longitudinal study of individuals with a mean age of 79 years at study entry, and observed up to a maximum of five times to their early 90s. Growth mixture modeling was employed to identify groups of individuals with similar trajectories of global cognitive function measured with the Mini-Mental State Examination (MMSE) in relation to time to death, accounting for childhood intelligence, education, the time to death from study entry, and health conditions (hypertension, diabetes, and cardiovascular disease). Two distinct groups of individuals (classes) were identified: a smaller class (18% of the sample) of individuals whose MMSE scores dropped linearly with about 0.5 MMSE points per year closer to death and a larger group (82% of the sample) with stable MMSE across the study period. Only childhood intelligence was found to be associated with an increased probability of belonging to the stable class of cognitive functioning prior to death (odds ratio = 1.08, standard error = 0.02, p ≤ .001). These findings support a protective role of childhood intelligence, a marker of cognitive reserve, against the loss of cognitive function prior to death. Our results also suggest that terminal decline is not necessarily a normative process. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Longitudinal associations between hearing loss and general cognitive ability: The Lothian Birth Cohort 1936

Hearing impairment is associated with poorer cognitive function in later life. We tested for the potential contribution of childhood cognitive ability to this relationship. Childhood cognitive ability is strongly related to cognitive function in older age, and may be related to auditory function through its association with hearing impairment risk factors. Using data from the Lothian Birth Cohort, 1936, we tested whether childhood cognitive ability predicted later-life hearing ability then whether this association was mediated by demographic or health differences. We found that childhood cognitive ability was negatively associated with hearing impairment risk at age 76 (odds ratio = .834, p = .042). However, this association was nonsignificant after subsequent adjustment for potentially mediating demographic and health factors. Next, we tested whether associations observed in older age between hearing impairment and general cognitive ability level or change were accounted for by childhood cognitive ability. At age 76, in the minimally adjusted model, hearing impairment was associated with poorer general cognitive ability level (β = -.119, p = .030) but was not related to decline in general cognitive ability. The former association became nonsignificant after additional adjustment for childhood cognitive ability (β = -.068, p = .426) suggesting that childhood cognitive ability contributes (potentially via demographic and health differences) to the association between levels of hearing and cognitive function in older age. Further work is needed to test whether early life cognitive ability also contributes to the association (documented in previous studies) between older-age hearing impairment and cognitive decline. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Work participation in ADHD and associations with social characteristics, education, lifetime depression, and ADHD symptom severity

The literature refers to high rates of occupational failure in the population of adults with ADHD. The explanation for this is less known. The aim of the present study was to examine associations between social characteristics and clinical features of adults with ADHD and their occupational outcome. Out of 1050 patients diagnosed with ADHD in a specialized outpatient clinic between 2005 and 2017, 813 (77.4%) agreed to participate in the study. ADHD was diagnosed according to DSM-IV criteria, and ADHD subtypes recorded accordingly. Lifetime depression was diagnosed using the specific module of the Mini International Neuropsychiatric Interview. Occupational status and other social characteristics like marital status and living with children were recorded. Intelligence (IQ) and symptom severity of ADHD (ASRS score) were assessed in subsamples of participants (n = 526 and n = 567, respectively). In this sample of adults with ADHD (mean age 36.9 years, 48.5% women), 55.3% of the women and 63.7% of the men were working at the time of inclusion. Work participation was associated with being male, being married or cohabitant, or living with children, as well as a life story without major depression. Age, education, ADHD subtype, and ADHD symptom severity were not significantly associated with work participation. Neither was IQ when adjusted for other covariates. Occupational outcome in adults with ADHD appears to be more associated with social characteristics and a history of depression, rather than with IQ, ADHD subtype, or ADHD symptom severity.

Young adult cognitive ability and subsequent major depression in a cohort of 666,804 Danish men

BACKGROUND

Early life cognitive ability (CA) might influence the risk of developing major depression (MD). The aim was to investigate the association between young adult CA and subsequent MD in relation to different MD disease characteristics.

METHODS

Information on CA was assessed at conscription board examinations 1957-1984 (mean age 19 years) and information on MD was based on hospital diagnosis retrieved from Danish Patient registers 1969-2015. Associations between CA and MD were examined using Cox regression analyses.

RESULTS

A total of 666,804 men (born 1939-1959) were followed and 25,841 (3.9%) developed MD during a mean follow-up of 40.8 years. Lower CA was associated with an increased risk of incident MD. The association was stronger for early-onset (<60 years) (HR_{per1SDdecrease} = 1.23; 95%CI:1.21,1.24) compared to late-onset (≥60 years) MD (HR_{per1SDdecrease} = 1.14; 95%CI:1.11,1.16), but CA was not related to number of depressive episodes. The association was stronger for single depressive episodes (HR_{per1SDdecrease} = 1.21; 95%CI:1.19,1.23) compared to recurrent depression (HR_{per1SDdecrease} = 1.13; 95%CI:1.09,1.16), while the strength of the association did not differ according to MD disease severity (ICD10: mild, moderate, and severe depression).

LIMITATIONS

The study sample only included men and only MD cases diagnosed at hospital were included which limits the generalizability.

CONCLUSION

Low CA could be a risk factor for especially early onset MD in men, whereas the influence of CA on re-occurrence seems less strong. Lower pre-morbid CA increases the risk of MD and should therefore be part of the depression risk assessment in clinical practice.

Intelligence in youth and health behaviours in middle age

OBJECTIVE

We investigated the association between intelligence in youth and a range of health-related behaviours in middle age.

METHOD

Participants were the 5347 men and women who responded to the National Longitudinal Survey of Youth 1979 (NLSY-79) 2012 survey. IQ was recorded with the Armed Forces Qualification Test (AFQT) when participants were aged 15 to 23 years of age. Self-reports on exercise (moderate activity, vigorous activity, and strength training), dietary, smoking, drinking, and oral health behaviours were recorded when participants were in middle age (mean age = 51.7 years). A series of regression analyses tested for an association between IQ in youth and the different health related behaviours in middle age, while adjusting for childhood socio-economic status (SES) and adult SES.

RESULTS

Higher IQ in youth was significantly associated with the following behaviours that are beneficial to health: being more likely to be able to do moderate cardiovascular activity (Odds Ratio, 95% CI) (1.72, 1.35 to 2.20, p < .001) and strength training (1.61, 1.37 to 1.90, p < .001); being less likely to have had a sugary drink in the previous week (0.75, 0.71 to 0.80, p < .001); a lower likelihood of drinking alcohol heavily (0.67, 0.61 to 0.74, p < .001); being less likely to smoke (0.60, 0.56 to 0.65, p < .001); being more likely to floss (1.47, 1.35 to 1.59, p < .001); and being more likely to say they "often" read the nutritional information (1.20, 1.09 to 1.31, p < .001) and ingredients (1.24, 1.12 to 1.36, p < .001) on food packaging compared to always reading them. Higher IQ was also linked with dietary behaviours that may or may not be linked with poorer health outcomes (i.e. being more likely to have skipped a meal (1.10, 1.03 to 1.17, p = .005) and snacked between meals (1.37, 1.26 to 1.50, p < .001) in the previous week). An inverted u-shaped association was also found between IQ and the number of meals skipped per week. Higher IQ was also linked with behaviours that are known to be linked with poorer health (i.e. a higher likelihood of drinking alcohol compared to being abstinent from drinking alcohol (1.58, 1.47 to 1.69, p < .001)). A u-shaped association was found between IQ and the amount of alcohol consumed per week and an inverted u-shaped association was found between IQ and the number of cigarettes smoked a day. Across all outcomes, adjusting for childhood SES tended to attenuate the estimated effect size only slightly. Adjusting for adult SES led to more marked attenuation but statistical significance was maintained in most cases.

CONCLUSION

In the present study, a higher IQ in adolescence was associated with a number of healthier behaviours in middle age. In contrast to these results, a few associations were also identified between higher intelligence and behaviours that may or may not be linked with poor health (i.e. skipping meals and snacking between meals) and with behaviours that are known to be linked with poor health (i.e. drinking alcohol and the number of cigarettes smoked). To explore mechanisms of association, future studies could test for a range of health behaviours as potential mediators between IQ and morbidity or mortality in later life.

Comorbid psychiatric disorders in a clinical sample of adults with ADHD, and associations with education, work and social characteristics: a cross-sectional study

OBJECTIVES

Adults with attention-deficit hyperactive disorder (ADHD) report high rates of comorbid disorders, educational and occupational failure, and family instability. The aim of this study was to examine the prevalence of comorbid psychiatric disorders in a clinical population of adults with ADHD and to examine associations between educational level, work participation, social characteristics and the rates of psychiatric comorbidity.

METHODS

Out of 796 patients diagnosed with ADHD in a specialised outpatient clinic in Oslo, Norway, 548 (68%) agreed to participate in this cross-sectional study: 277 women and 271 men. ADHD was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Comorbid disorders were diagnosed using the Mini-International Neuropsychiatric Interview.

RESULTS

In this clinical sample, 53.5% had at least one current comorbid psychiatric disorder. The most prevalent disorders were major depression, substance use disorders and social phobia. Women had more eating disorders than men, whereas men had more alcohol and substance use disorders. Education above high school level (>12 years) and work participation were associated with lower rates of comorbid disorders (adjusted ORs 0.52 and 0.63, respectively). Gender, age, marital status, living with children or living in a city were not associated with comorbidity.

CONCLUSIONS

Adult ADHD is associated with high rates of comorbid psychiatric disorders, irrespective of gender and age. It appears that higher education and work participation are related to lower probability of comorbidity.

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.

Childhood intelligence in relation to major causes of death in 68 year follow-up: prospective population study

Objectives To examine the association between intelligence measured in childhood and leading causes of death in men and women over the life course.Design Prospective cohort study based on a whole population of participants born in Scotland in 1936 and linked to mortality data across 68 years of follow-up.Setting Scotland.Participants 33 536 men and 32 229 women who were participants in the Scottish Mental Survey of 1947 (SMS1947) and who could be linked to cause of death data up to December 2015.Main outcome measures Cause specific mortality, including from coronary heart disease, stroke, specific cancer types, respiratory disease, digestive disease, external causes, and dementia.Results Childhood intelligence was inversely associated with all major causes of death. The age and sex adjusted hazard ratios (and 95% confidence intervals) per 1 SD (about 15 points) advantage in intelligence test score were strongest for respiratory disease (0.72, 0.70 to 0.74), coronary heart disease (0.75, 0.73 to 0.77), and stroke (0.76, 0.73 to 0.79). Other notable associations (all P<0.001) were observed for deaths from injury (0.81, 0.75 to 0.86), smoking related cancers (0.82, 0.80 to 0.84), digestive disease (0.82, 0.79 to 0.86), and dementia (0.84, 0.78 to 0.90). Weak associations were apparent for suicide (0.87, 0.74 to 1.02) and deaths from cancer not related to smoking (0.96, 0.93 to 1.00), and their confidence intervals included unity. There was a suggestion that childhood intelligence was somewhat more strongly related to coronary heart disease, smoking related cancers, respiratory disease, and dementia in women than men (P value for interactions <0.001, 0.02, <0.001, and 0.02, respectively).Childhood intelligence was related to selected cancer presentations, including lung (0.75, 0.72 to 0.77), stomach (0.77, 0.69 to 0.85), bladder (0.81, 0.71 to 0.91), oesophageal (0.85, 0.78 to 0.94), liver (0.85, 0.74 to 0.97), colorectal (0.89, 0.83 to 0.95), and haematopoietic (0.91, 0.83 to 0.98). Sensitivity analyses on a representative subsample of the cohort observed only small attenuation of the estimated effect of intelligence (by 10-26%) after adjustment for potential confounders, including three indicators of childhood socioeconomic status. In a replication sample from Scotland, in a similar birth year cohort and follow-up period, smoking and adult socioeconomic status partially attenuated (by 16-58%) the association of intelligence with outcome rates.Conclusions In a whole national population year of birth cohort followed over the life course from age 11 to age 79, higher scores on a well validated childhood intelligence test were associated with lower risk of mortality ascribed to coronary heart disease and stroke, cancers related to smoking (particularly lung and stomach), respiratory diseases, digestive diseases, injury, and dementia.

Childhood cognitive ability and smoking initiation, relapse and cessation throughout adulthood: evidence from two British cohort studies

AIMS

To test the relationship between early cognitive ability and major changes in smoking habits across adulthood, and test whether educational attainment mediates these associations.

DESIGN

Prospective observational study to examine the link between cognitive ability and smoking initiation, relapse and cessation at multiple time-points throughout adulthood in a pooled analysis of two cohorts.

SETTING

Great Britain 1981-2013.

PARTICIPANTS

A total of 16 653 participants from two British cohorts; 7191 from the 1970 British Cohort Study (BCS) and 9462 from the 1958 National Child Development Study (NCDS). Participants were 52.9% female and 27.3% were smokers, 24.8% were ex-smokers and 47.9% reported never smoking.

MEASUREMENTS

Cognitive ability was assessed at age 10 years in the BCS and 11 years in the NCDS. Outcomes were smoking initiation, relapse and cessation derived from changes in smoking status observed across five time-points between ages 26-42 in the BCS and six time-points between ages 23-55 in the NCDS. Educational attainment was examined as a mediating variable. Controls were age, gender, social class, self-control, psychological distress, parental smoking and a study indicator (BCS/NCDS).

FINDINGS

In adjusted regression models, a 1 standard deviation increase in cognitive ability predicted a 0.5 percentage point (95% CI = -0.9 to -0.1) reduced probability of smoking and a 2.9 percentage point (95% CI = 2.1-3.7) higher probability of smoking cessation throughout adulthood, but did not change the likelihood of smoking relapse significantly. Differences in educational attainment explained approximately half the association between childhood cognitive ability and smoking initiation/cessation.

CONCLUSIONS

Lower cognitive ability, measured in childhood before smoking is initiated, appears to predict a higher likelihood of taking up smoking and a lower likelihood of quitting in adulthood. Educational attainment appears to mediate this effect: children with higher cognitive ability tend to become more highly educated adults which, in turn, predicts lower rates of smoking initiation and increased rates of smoking cessation.

Childhood academic ability in relation to cigarette, alcohol and cannabis use from adolescence into early adulthood: Longitudinal Study of Young People in England (LSYPE)

OBJECTIVES

Our aim was to determine the association between childhood academic ability and the onset and persistence of tobacco, alcohol and cannabis use across adolescence in a representative sample of English schools pupils. Previous research has produced conflicting findings.

DESIGN

Data from 7 years of the Longitudinal Study of Young People in England (LSYPE), 2004-2010 (age 13/14-19/20).

SETTING

Self-completion questionnaires during home visits, face-to-face interviews and web-based questionnaires.

PARTICIPANTS

Data from 6059 participants (3093 females) with information on academic ability around age 11 and health behaviours from age 13/14 to 16/17 (early adolescence) and from age 18/19 to 19/20 (late adolescence).

OUTCOME MEASURES

Regularity of cigarette smoking, alcohol drinking and cannabis use from early to late adolescence.

RESULTS

In multinomial logistic regression models adjusting for a range of covariates, the high (vs low) academic ability reduced the risk of persistent cigarette smoking (RR=0.62; CI 95% 0.48 to 0.81) in early adolescence. High (vs low) academic ability increased the risk of occasional (RR=1.25; CI 95% 1.04 to 1.51) and persistent (RR=1.83; CI 95% 1.50 to 2.23) regular alcohol drinking in early adolescence and persistent (RR=2.28; CI 95% 1.84 to 2.82) but not occasional regular alcohol drinking in late adolescence. High (vs low) academic ability was also positively associated with occasional (RR=1.50; CI 95% 1.22 to 1.83) and persistent (RR=1.91; CI 95% 1.57 to 2.34) cannabis use in late adolescence.

CONCLUSIONS

In a sample of over 6000 young people in England, high childhood academic at age 11 is associated with a reduced risk of cigarette smoking but an increased risk of drinking alcohol regularly and cannabis use. These associations persist into early adulthood, providing evidence against the hypothesis that high academic ability is associated with temporary 'experimentation' with substance use.

An International Evaluation of Cognitive Reserve and Memory Changes in Early Old Age in 10 European Countries

BACKGROUND

Cognitive reserve was postulated to explain individual differences in susceptibility to ageing, offering apparent protection to those with higher education. We investigated the association between education and change in memory in early old age.

METHODS

Immediate and delayed memory scores from over 10,000 individuals aged 65 years and older, from 10 countries of the Survey of Health, Ageing and Retirement in Europe, were modeled as a function of time in the study over an 8-year period, fitting independent latent growth models. Education was used as a marker of cognitive reserve and evaluated in association with memory performance and rate of change, while accounting for income, general health, smoking, body mass index, gender, and baseline age.

RESULTS

In most countries, more educated individuals performed better on both memory tests at baseline, compared to those less educated. However, education was not protective against faster decline, except for in Spain for both immediate and delayed recall (0.007 [SE = 0.003] and 0.006 [SE = 0.002]), and Switzerland for immediate recall (0.006 [SE = 0.003]). Interestingly, highly educated Italian respondents had slightly faster declines in immediate recall (-0.006 [SE = 0.003]).

CONCLUSIONS

We found weak evidence of a protective effect of education on memory change in most European samples, although there was a positive association with memory performance at individuals' baseline assessment.

Spies C, Pischon T. Cognitive Reserve and the Risk of Postoperative Cognitive Dysfunction

BACKGROUND

Post-operative cognitive dysfunction (POCD) occurs in 10 to 54% of older patients during the first few weeks after surgery, but little is known about risk factors predisposing to POCD.

METHODS

Systematic literature review and meta-analysis of cognitive reserve indicators and POCD risk.

RESULTS

Fifteen studies on 5104 patients were included. Follow-up periods spanned 1 day to 6 months. Educational level was the most commonly assessed cognitive reserve indicator, and a longer time spent in education was associated with a reduced risk of POCD (relative risk [RR] per year increment 0.90; 95% confidence interval: [0.87; 0.94]), i.e. each year increase in education was associated with a 10% reduced risk. Similar findings were made for some analyses on education as a categorical predictor (high school versus further/higher education, RR 1.71, [1.30; 2.25]; lower than high school versus further/higher education, RR 1.69, [1.17; 2.44]) though risk was equivalent for patients with high school education and those with lower than high school education (RR 1.02; [0.78; 1.32]).

CONCLUSION

Patients with a relatively higher level of education are at reduced risk of POCD. Risk stratification of surgical patients according to educational level may prove useful.

Dietary Iodine Exposure and Brain Structures and Cognition in Older People. Exploratory Analysis in the Lothian Birth Cohort 1936

BACKGROUND

Iodine deficiency is one of the three key micronutrient deficiencies highlighted as major public health issues by the World Health Organisation. Iodine deficiency is known to cause brain structural alterations likely to affect cognition. However, it is not known whether or how different (lifelong) levels of exposure to dietary iodine influences brain health and cognitive functions.

METHODS

From 1091 participants initially enrolled in The Lothian Birth Cohort Study 1936, we obtained whole diet data from 882. Three years later, from 866 participants (mean age 72 yrs, SD±0.8), we obtained cognitive information and ventricular, hippocampal and normal and abnormal tissue volumes from brain structural magnetic resonance imaging scans (n=700). We studied the brain structure and cognitive abilities of iodine-rich food avoiders/low consumers versus those with a high intake in iodine-rich foods (namely dairy and fish).

RESULTS

We identified individuals (n=189) with contrasting diets, i) belonging to the lowest quintiles for dairy and fish consumption, ii) milk avoiders, iii) belonging to the middle quintiles for dairy and fish consumption, and iv) belonging to the middle quintiles for dairy and fish consumption. Iodine intake was secured mostly though the diet (n=10 supplement users) and was sufficient for most (75.1%, median 193 µg/day). In individuals from these groups, brain lateral ventricular volume was positively associated with fat, energy and protein intake. The associations between iodine intake and brain ventricular volume and between consumption of fish products (including fish cakes and fish-containing pasties) and white matter hyperintensities (p=0.03) the latest being compounded by sodium, proteins and saturated fats, disappeared after type 1 error correction.

CONCLUSION

In this large Scottish older cohort, the proportion of individuals reporting extreme (low vs. high)/medium iodine consumption is small. In these individuals, low iodine-rich food intake was associated with increased brain volume shrinkage, raising an important hypothesis worth being explored for designing appropriate guidelines.

Structural Imaging Changes and Behavioral Correlates in Patients with Crohn's Disease in Remission

Background: Crohn’s disease (CD) is a subtype of inflammatory bowel disease caused by immune-mediated inflammation in the gastrointestinal tract. The extent of morphologic brain alterations and their associated cognitive and affective impairments remain poorly characterized.

Aims: We used magnetic resonance imaging to identify structural brain differences between patients with Crohn’s disease in remission compared to age-matched healthy controls and evaluated for structural-behavioral correlates.

Methods: Nineteen patients and 20 healthy, age-matched controls were recruited in the study. Group differences in brain morphometric measures and correlations between brain measures and performance on a cognitive task, the verbal fluency (VF) task, were examined. Correlations between brain measures and cognitive measures as well as self-reported measures of depression, personality, and affective scales were examined.

Results: Patients showed significant cortical thickening in the left superior frontal region compared to controls. Significant group differences were observed in sub-cortical volume measures in both hemispheres. Investigation of brain-behavior correlations revealed significant group differences in the correlation between cortical surface area and VF performance, although behavioral performance was equivalent between the two groups. The left middle temporal surface area was a significant predictor of VF performance with controls showing a significant positive correlation between these measures, and patients showing the opposite effect.

Conclusion: Our results indicate key differences in structural brain measures in patients with CD compared to controls. Additionally, correlation between brain measures and behavioral responses suggest there may be a neural basis to the alterations in patients’ cognitive and affective responses.

Associations Between Childhood Cognition and Cardiovascular Events in Adulthood: A Systematic Review and Meta-analysis

BACKGROUND

The success of behavioural interventions to optimize cardiovascular health is dependent on adequate cognitive functioning beginning in early life. In this study we aimed to systematically review studies that examined associations between childhood cognition and cardiovascular disease (CVD) events in adulthood.

METHODS

This study followed the Meta-analysis Of Observational Studies in Epidemiology guidelines to systematically examine associations between childhood cognition and adult CVD, coronary heart disease, and stroke hospitalization or mortality events. Literature was retrieved from EMBASE, MEDLINE, PsycInfo, and CINAHL.

RESULTS

Five longitudinal studies that examined links between childhood cognition and CVD in adulthood were included. Pooled estimates of unadjusted CVD events indicated a relative risk of 1.23 (95% confidence interval, 1.12-1.34) per standard deviation decrease in childhood IQ, whereas the pooled estimate adjusted for biopsychosocial confounding factors indicated an overall relative risk of 1.16 (95% confidence interval, 1.07-1.26).

CONCLUSIONS

Lower childhood IQ is associated with an increased risk of cardiovascular events in adulthood, even after adjustment for confounding variables. Future research should examine the behavioural mechanisms by which these risks are mediated to optimize cardiovascular health.

Childhood cognitive ability and body composition in adulthood

Background:

Childhood cognitive ability has been identified as a novel risk factor for adulthood overweight and obesity as assessed by adult body mass index (BMI). BMI does not, however, distinguish fat-free and metabolically harmful fat tissue. Hence, we examined the associations between childhood cognitive abilities and body fat percentage (BF%) in young adulthood.

Methods:

Participants of the Arvo Ylppö Longitudinal Study (n=816) underwent tests of general reasoning, visuomotor integration, verbal competence and language comprehension (M=100; s.d.=15) at the age of 56 months. At the age of 25 years, they underwent a clinical examination, including measurements of BF% by the InBody 3.0 eight-polar tactile electrode system, weight and height from which BMI (kg m⁻²) was calculated and waist circumference (cm).

Results:

After adjustments for sex, age and BMI-for-age s.d. score at 56 months, lower general reasoning and visuomotor integration in childhood predicted higher BMI (kg m⁻²) increase per s.d. unit decrease in cognitive ability (−0.32, 95% confidence interval −0.60,−0.05; −0.45, −0.75,−0.14, respectively) and waist circumference (cm) increase per s.d. unit decrease in cognitive ability (−0.84, −1.56,−0.11; −1.07,−1.88,−0.26, respectively) in adulthood. In addition, lower visuomotor integration predicted higher BF% per s.d. unit decrease in cognitive ability (−0.62,−1.14,−0.09). Associations between general reasoning and BMI/waist were attenuated when adjusted for smoking, alcohol consumption, intake of fruits and vegetables and physical activity in adulthood, and all associations, except for visuomotor integration and BMI, were attenuated when adjusted for parental and/or own attained education and/or birth weight.

Conclusions:

Of the measured childhood cognitive abilities, only lower visuomotor integration was associated with BF% in adulthood. This challenges the view that cognitive ability, at least when measured in early childhood, poses a risk for adiposity in adulthood, as characterized by higher BF%.

Do Executive Function and Impulsivity Predict Adolescent Health Behaviour after Accounting for Intelligence? Findings from the ALSPAC Cohort

Objective

Executive function, impulsivity, and intelligence are correlated markers of cognitive resource that predict health-related behaviours. It is unknown whether executive function and impulsivity are unique predictors of these behaviours after accounting for intelligence.

Methods

Data from 6069 participants from the Avon Longitudinal Study of Parents and Children were analysed to investigate whether components of executive function (selective attention, attentional control, working memory, and response inhibition) and impulsivity (parent-rated) measured between ages 8 and 10, predicted having ever drunk alcohol, having ever smoked, fruit and vegetable consumption, physical activity, and overweight at age 13, after accounting for intelligence at age 8 and childhood socioeconomic characteristics.

Results

Higher intelligence predicted having drunk alcohol, not smoking, greater fruit and vegetable consumption, and not being overweight. After accounting for intelligence, impulsivity predicted alcohol use (odds ratio = 1.10; 99% confidence interval = 1.02, 1.19) and smoking (1.22; 1.11, 1.34). Working memory predicted not being overweight (0.90; 0.81, 0.99).

Conclusions

After accounting for intelligence, executive function predicts overweight status but not health-related behaviours in early adolescence, whilst impulsivity predicts the onset of alcohol and cigarette use, all with small effects. This suggests overlap between executive function and intelligence as predictors of health behaviour in this cohort, with trait impulsivity accounting for additional variance.

Fathers' intelligence measured at age 18-20 years is associated with offspring smoking: linking the Swedish 1969 conscription cohort to the Swedish Survey of Living Conditions

Background

An association between lower IQ of parents, measured early in life, and smoking among their offspring has been reported. The extent to which other background factors account for this association is unknown.

Methods

Data on IQ, smoking, mental health, social class, parental divorce and social problems in a cohort of men born during 1949–1951 and conscripted for military service in 1969 were linked to smoking data on 682 offspring interviewed in the Swedish Surveys of Living Conditions 1984–2009.

Results

In an age-adjusted model, a one-step decrease on a stanine scale was associated with an OR of 1.19 (95% CI 1.04 to 1.35) for offspring smoking. Adjusting for father's socioeconomic background and smoking, mental illness and social problems in youth only marginally lowered the OR's.

Conclusions

Lower IQ among fathers measured at ages 18–20 years was associated with smoking in their offspring. The association was not explained by father's social class in childhood or a higher prevalence of mental illness, social problems or smoking measured among the fathers in their late adolescence.

Intelligence in childhood and atherosclerosis of the carotid and peripheral arteries in later life: the Lothian Birth Cohort 1936

OBJECTIVE

There is some evidence that people who score higher on tests of intelligence in childhood have lower carotid intima-media thickness and higher ankle brachial index in middle age. These findings need replicating in other, older populations. We investigated the prospective relationship between intelligence in childhood and atherosclerosis in the carotid and peripheral arteries at age 73 years.

METHODS

Participants were 713 members of the Lothian Birth Cohort 1936 whose intelligence was assessed at age 11 years. At age 73 years, carotid intima-media thickness and degree of stenosis were measured using ultrasound imaging; ankle-brachial index was measured using Doppler ultrasound.

RESULTS

There were no significant associations between intelligence at age 11 and measures of atherosclerosis at age 73. In age- and sex-adjusted analyses, for a standard deviation higher score in intelligence, intima-media thickness (x 10) was lower by 0.07 (-0.20, 0.06) mm and ankle brachial index (x 10) was lower by 0.09 (-0.24, 0.07); odds ratios for having carotid stenosis >25% or peripheral arterial disease were 0.98 (0.82, 1.16) and 1.05 (0.81, 1.36) respectively.

CONCLUSION

In this study of people aged 73 years, higher childhood intelligence was not associated with reduced risk of atherosclerosis in the carotid or peripheral arteries.

IQ and level of alcohol consumption—findings from a national survey of Swedish conscripts

BACKGROUND

Studies of the association between IQ and alcohol consumption have shown conflicting results. The aim of this study was to investigate the association between IQ test results and alcohol consumption, measured as both total alcohol intake and pattern of alcohol use.

METHODS

The study population consists of 49,321 Swedish males born 1949 to 1951 who were conscripted for Swedish military service 1969 to 1970. IQ test results were available from tests performed at conscription. Questionnaires performed at conscription provided data on total alcohol intake (consumed grams of alcohol/wk) and pattern of drinking. Multinomial and binomial logistic regressions were performed on the cross-sectional data to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Adjustments were made for socioeconomic position as a child, psychiatric symptoms and emotional stability, and father's alcohol habits.

RESULTS

We found an increased OR of 1.20 (1.17 to 1.23) for every step decrease on the stanine scale to be a high consumer versus a light consumer of alcohol. For binge drinking, an increased OR of 1.09 (95% CI = 1.08 to 1.11) was estimated for every step decrease on the stanine scale. Adjustment for confounders attenuated the associations. Also, IQ in adolescence was found to be inversely associated with moderate/high alcohol consumption measured in middle age.

CONCLUSIONS

We found that lower results on IQ tests are associated with higher consumption of alcohol measured in terms of both total alcohol intake and binge drinking in Swedish adolescent men.

Stanovich's arguments against the "adaptive rationality" project: An assessment

This paper discusses Stanovich's appeal to individual differences in reasoning and decision-making to undermine the "adaptive rationality" project put forth by Gigerenzer and his co-workers. I discuss two different arguments based on Stanovich's research. First, heterogeneity in the use of heuristics seems to be at odds with the adaptationist background of the project. Second, the existence of correlations between cognitive ability and susceptibility to cognitive bias suggests that the "standard picture of rationality" (Stein, 1996, 4) is normatively adequate. I argue that, as matters stand, none of the arguments can be seen as fully compelling. Nevertheless, my discussion is not only critical of Stanovich's research, as I also show that (and how) his research can push forward the so-called "rationality debate" by encouraging greater theoretical and experimental work.

IQ and obesity in adolescence: a population-based, cross-sectional study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Low IQ is associated with high BMI in childhood. There are inconsistent findings on the association between low SES and high BMI. Youth with low IQ have been reported to have poorer health behaviors, such as poor nutrition and less physical activity.

WHAT THIS STUDY ADDS

Low IQ is significantly associated with obesity for both male and female adolescents, though more strongly for female adolescents. Physical activity has a mediating effect on the association between low IQ and obesity among both male and female adolescents, though more strongly for male adolescents. The association between low IQ and obesity is strongest among adolescents from high SES backgrounds.

BACKGROUND

Previous studies have shown an association between low intelligence quotient (IQ), high body mass index and low socioeconomic status (SES).

OBJECTIVES

This study examined the cross-sectional association between IQ and obesity, exploring the roles of gender, SES and physical activity in this association.

METHODS

Subjects were 235,663 male and 169,259 female adolescents assessed by the Israeli military draft board.

RESULTS

Low IQ was significantly associated with increased odds of obesity among male (odds ratio [OR] = 1.44, 95% confidence interval [CI] = 1.36-1.52) and female adolescents (OR = 1.61, 95% CI = 1.51-1.73); this association was significantly stronger among female adolescents. Sobel tests indicated that physical activity had a significant mediating effect on this association for male and female adolescents, although more strongly for male adolescents. Dividing the sample according to SES, the association between low IQ and obesity was strongest in the high SES group (male adolescents: OR = 1.26, 95% CI = 1.10-1.43, female adolescents: OR = 1.61, 95% CI = 1.38-1.89), even when controlling for physical activity.

CONCLUSIONS

The findings suggest that low IQ is associated with increased odds of obesity, particularly in female adolescents and in adolescents with high SES. Physical activity has a mediating effect on this association, although more strongly for male than for female adolescents. Public health measures on decreasing obesity might focus on these groups.

Measurement confounding affects the extent to which verbal IQ explains social gradients in mortality

BACKGROUND

IQ is thought to explain social gradients in mortality. IQ scores are based roughly equally on Verbal IQ (VIQ) and Performance IQ tests. VIQ tests, however, are suspected to confound true verbal ability with socioeconomic status (SES), raising the possibility that associations between SES and IQ scores might be overestimated. We examined, first, whether two of the most common types of VIQ tests exhibited differential item functioning (DIF) favouring persons of higher SES and/or majority race/ethnicity. Second, we assessed what impact, if any, this had on estimates of the extent to which VIQ explains social gradients in mortality.

METHODS

Data from the General Social Survey-National Death Index cohort, a US population representative dataset, was used. Item response theory models queried social-factor DIF on the Thorndike Verbal Intelligence Scale and Wechsler Adult Intelligence Scales, Revised Similarities test. Cox models examined mortality associations among SES and VIQ scores corrected and uncorrected for DIF.

RESULTS

When uncorrected for DIF, VIQ was correlated with income, education, occupational prestige and race, with correlation coefficients ranging between |0.12| and |0.43|. After correcting for DIF, correlations ranged from |0.06| to |0.16|. Uncorrected VIQ scores explained 11-40% of the Relative Index of Inequalities in mortality for social factors, while DIF-corrected scores explained 2-29%.

CONCLUSIONS

Two of the common forms of VIQ tests appear confound verbal intelligence with SES. Since these tests appear in most IQ batteries, circumspection may be warranted in estimating the amount of social inequalities in mortality attributable to IQ.