Intelligence, health and death

Effect of strategic memory advanced reasoning training (SMART) therapy for enhancing final-year high school students career choices

The SMART program improves students' memory, reasoning, and strategic thinking skills, crucial for academic success and career planning. This study explored the effect of Strategic Memory Advanced Reasoning Training (SMART) for final-year high school students, aiming to enhance their decision-making abilities and prepare them for University. Based on the literature, nine hypotheses were developed with SMART program implementation therapy as an independent variable with four sub-variables: cognitive skills, professional development, social skills, and academic skills, and their impact on the dependent variable, such as career decision-making. Using a smart partial least square-structural equation modeling (PLS-SEM) on 284 high school students, confirmatory factor analysis (CFA) and structural equation modeling (SEM) was implemented to confirm the measurement model. Path analysis was conducted to determine the relationship between independent and dependent variables. Results of the study revealed that SMART therapy significantly enhances cognitive abilities, academic performance, personal development, and social skills, collectively contributing to better career decision-making among final-year high school students. However, the direct impact of SMART on career decision-making was not supported, indicating that additional factors, such as social and emotional influences, play a role. These findings suggest that integrating SMART therapy into high school curricula can better prepare students for future challenges and career opportunities, aligning with Sustainable Development Goal 4 (Quality Education). A collaborative approach among stakeholders, policy support, and innovative practices are recommended to overcome potential obstacles and ensure the successful implementation of SMART therapy in educational settings.

Causal Relationship Between Intelligence, Noncognitive Education, Cognition and Urinary Tract or Kidney Infection: A Mendelian Randomization Study

Background

The occurrence of urinary tract or kidney infection is correlated with intelligence, noncognitive education and cognition, but the causal relationship between them remains uncertain, and which risk factors mediate this causal relationship remains unknown.

Methods

The intelligence (n=269,867), noncognitive education (n=510,795) and cognition data (n=257,700) were obtained from genome-wide association studies (GWAS) conducted in individuals of European ethnicities. The genetic associations between these factors and urinary tract or kidney infection (UK Biobank, n=397,867) were analyzed using linkage disequilibrium score regression. We employed a two-sample univariate and multivariate Mendelian randomization to evaluate the causal relationship, and utilized a two-step Mendelian randomization to examine the involvement of 28 potential mediators and their respective mediating proportions.

Results

The genetic correlation coefficients of intelligence, noncognitive education, cognition, and urinary tract or kidney infection were -0.338, -0.218, and -0.330. The Mendelian randomization using the inverse variance weighted method revealed each 1-SD increase in intelligence, the risk of infection decreased by 15.9%, while after adjusting for noncognitive education, the risk decreased by 20%. For each 1-SD increase in noncognitive education, the risk of infection decreased by 8%, which further reduced to 7.1% after adjusting for intelligence and to 6.7% after adjusting for cognition. For each 1-SD increase in cognition, the risk of infection decreased by 10.8%, increasing to 11.9% after adjusting for noncognitive education. The effects of intelligence and cognition are interdependent. 2 out of 28 potential mediating factors exhibited significant mediation effects in the causal relationship between noncognitive education and urinary tract or kidney infection, with body mass index accounting for 12.1% of the mediation effect and smoking initiation accounting for 14.7%.

Conclusion

Enhancing intelligence, noncognitive education, and cognition can mitigate the susceptibility to urinary tract or kidney infection. Noncognitive education exhibited independent effect, while body mass index and smoking initiation assuming a mediating role.

Cognitive ability in offspring conscripts and cardiovascular disease risk in extended family members: assessing the impact of modifiable risk factors on familial risk

BACKGROUND

Previous studies have demonstrated an inverse association between cognitive ability (CA) and risk of cardiovascular diseases (CVDs). This study aims to investigate the associations between CA in offspring and CVD mortality in relatives of the parental generation (ie, parents, aunts/uncles (A/U) and the partners of A/U) and assesses the role of modifiable risk factors on these associations.

METHODS

This longitudinal study included nearly 3 million adults who were followed up from age 45 until death. Data for participants were obtained through the linkage of various Norwegian surveys and registries. HRs for CVD mortality among the parental generation in relation to offspring CA were estimated using Cox proportional hazards regression.

RESULTS

One standard deviation increase in CA was associated with a 23%, 17%, 9% and 9% CVD mortality reduction in mothers (HR: 0.77, 95% CI (0.74, 0.81)), fathers (0.83, (0.81, 0.86)), A/U (0.91, (0.87, 0.94)) and A/U partners (0.91, (0.89, 0.94)), respectively. Accounting for modifiable risk factors in the parental generation attenuated the association in mothers from 23% to 9% (0.91, (0.87, 0.96)), fathers from 17% to 7% (0.93, (0.91, 0.96)), A/U from 9% to 1% (0.99, (0.96, 1.03)) and A/U partners from 9% to 2% (0.98, (0.95, 1.01)).

CONCLUSIONS

We observed an inverse CA-CVD association in all familial relationships including non-genetically related duos (offspring-A/U partners). CA and CVD probably have shared causes such as genetic and environmental components common to the family members. These associations were largely accounted for by modifiable risk factors.

The Path for Men from Young Adulthood Results of Cognitive Tests to Subclinical Atherosclerosis at Age 60: The Mediating Role of Socioeconomic Status, Lifestyle and Cardiovascular Disease Risk Factors-Results from a VIPVIZA Study

Background

The role of cognitive abilities in the development of arteriosclerotic disease is still not fully understood. The purpose of the present study was to evaluate the mediating role of lifestyle, socioeconomic status (SES) and conventional cardiovascular disease (CVD) risk factors in the association between cognitive ability at age 19 and subclinical atherosclerosis at age 60 years.

Methods

An observational study design was employed. Data on the results from cognitive tests of conscripts tested at age 19 were collected for 1009 men. At the age of 60, they were included in the trial VIsualiZation of asymptomatic Atherosclerotic disease for optimum cardiovascular prevention, which was conducted as part of the Västerbotten Intervention Program (VIPVIZA). VIPVIZA is a randomised controlled trial, aimed at primary prevention of CVD in Västerbotten County, Sweden. Prior to any intervention, they underwent carotid ultrasonography and CVD risk factor assessment. Lifestyle habits and marital status were self-reported, and education and urban or rural residency were registered. Crude associations between cognitive ability at age 19 and the risk of CVD, assessed with the European Systematic Coronary Risk Evaluation 2 (SCORE2), as well as subclinical atherosclerosis, as demonstrated by the presence of carotid plaques (no plaque, plaque unilateral, or plaque bilateral), were evaluated. A path-analytic model tested mediating factors from cognitive ability in young adulthood to subclinical atherosclerosis at age 60.

Results

Results from cognitive tests at age 19 were in separate unadjusted analyses inversely and linearly associated with SCORE2 and with subclinical atherosclerosis. The association with carotid plaque at age 60 was mainly indirect and mediated by adult SES, which in turn had its main effect through adherence to healthy lifestyle habits via CVD risk of carotid plaques.

Conclusions

Cognitive ability at age 19 is a factor that is upstream of adult SES and our study indicates that cognitive ability at a young age has long-term consequences via SES and lifestyle habits for CVD risk and atherosclerosis.

Clinical Trial Registration

NCT01849575, https://clinicaltrials.gov/study/NCT01849575?term=NCT01849575&rank=1.

Paternal intelligence affects school grades in children with and without ADHD - a register-based study

ADHD profoundly impacts educational attainment, quality of life, and health in young adults. However, certain subgroups of ADHD patients seem to do quite well, potentially due to differences in intelligence and socioeconomic status. Here we used paternal intelligence from the Swedish Defence Conscription and Assessment register, to investigate the role of genetic propensity for intelligence, on school performance in a large cohort of ADHD patients and matched controls. Patients treated for ADHD in Linköping, Sweden between 1995 and 2020 (n = 3262), sex- and age-matched controls (n = 9591) as well as their parents and siblings were identified using regional and national registers. Socioeconomic and demographic data, ADHD diagnosis and treatment and school grades at age 16 for the study population were extracted from Swedish National registers. We explored the associations between paternal intelligence and child school performance using linear mixed models and mediation analyses, taking a wide range of potential covariates into account. Results indicate that paternal intelligence was positively associated with standardized school grades in their offspring (Zadjusted=0.09, 95%CI 0.07, 0.10). This effect was present in both ADHD patients and controls, but ADHD patients had significantly lower standardized grades (Zadjusted=-1.03, 95%CI -1.08, -0.98). Child ADHD did not serve as a mediator for how paternal intelligence affected school grades. Our findings indicate that ADHD prevents children from reaching their academic potential at all levels of paternal intelligence. Increased understanding of the contributions of ADHD, intelligence, and SES to functional outcomes can help clinicians to better personalize interventions to the unique preconditions in each patient.

School performance and the social gradient in young adult death in Norway

Young adults from low socioeconomic backgrounds face an increased risk of early mortality. Here we utilize population-wide data from 17 Norwegian birth cohorts (N = 986,573) to assess whether this risk gradient was explained by early-life educational performance, specifically grade point average at 16 years of age. We show that the gradients in both parental education and income largely disappeared when adjusting for school performance in the models. Specifically, among boys, those with the lowest parental education had an unadjusted hazard ratio (HR) of 2.04 (95% confidence interval (CI) 1.86-2.22) compared with peers with the highest parental education, while for girls, the HR was 1.64 (95% CI 1.35-1.93). After adjusting for school performance, these estimates dropped to 0.99 (95% CI 0.79-1.19) for boys and 0.87 (95% CI 0.55-1.19) for girls. Similarly, the mortality risk for those from the lowest parental income quartile decreased from 1.79 (95% CI 1.67-1.91) to 1.25 (95% CI 1.12-1.38) for boys and from 1.63 (95% CI 1.44-1.83) to 1.24 (95% CI 1.03-1.46) for girls. Low educational performance remained strongly associated with early mortality in analyses accounting for unobserved heterogeneity at the family level; boys with a grade point average in the lowest quartile had an HR of 3.04 (95% CI 2.38-3.89), while for girls, the HR was 1.79 (95% CI 1.22-2.63). External causes of death, particularly accidents and poisoning, were most overrepresented among individuals with poor school performance.

A Nationwide, Population-Based Study of Intelligence and Hearing Loss among 3,104,670 Adolescents

PURPOSE

Epidemiological studies have demonstrated a relationship between general intelligence (GI) in youth and hearing loss (HL). However, no large-scale study assessed the relations of GI in late adolescence with conductive HL (CHL) and sensorineural HL (SNHL), stratified by severity. This study examined the connection between HL and GI in late adolescence.

METHODS

Cross-sectional study on mandatory premilitary recruitment data recorded during 1967-2019 of patients aged 17-19. We compared GI between SNHL, CHL, and those with normal hearing. In addition, we used logistic regression to measure the associations between HL and GI after adjuring for age, sex, education, and socioeconomic status.

RESULTS

Among 3,104,851 adolescents assessed, 20,075 (0.6%) exhibited HL. We categorized GI into three levels for analysis: low (lowest category), medium, and high (reference category). Adjusted odds ratios (ORs) revealed that SNHL was associated with lower GI levels, with ORs ranging from 1.3 (95% confidence interval [CI] 1.4-1.2) for the lowest GI category to 1.1 (95% CI 1.15-0.04) for the medium category. CHL (CHL) also demonstrated significant associations, with ORs from 1.8 (95% CI 1.9-1.6) for the lowest GI level to 1.1 (95% CI 1.2-0.9) for medium. Further analysis revealed a statistically significant, severity-dependent relationship between SNHL and the odds of being in the lowest GI quartile (Q1). Specifically, the ORs for SNHL ranged from 1.2 (95% CI 1.1-1.3) to 1.3 (95% CI 1.1-1.5) as severity increased, indicating a strong link between greater SNHL severity and reduced cognitive performance. In contrast, CHL did not show a consistent correlation between its severity and GI outcomes, with an OR of 1.6 (95% CI 1.2-2.3) across severity levels.

CONCLUSION

We report a strong relationship between HL and GI in late adolescence. SNHL, but not CHL, demonstrated a severity-based decline in GI. The results highlight the value of early, specifically targeted therapies for HL that consider its etiology and degree.

Associations of benzodiazepine use with cognitive ability and age-related cognitive decline

BACKGROUND

It remains uncertain whether long-term use of benzodiazepines is associated with age-related cognitive decline, and if cognitive ability in early life is the driver of any association. This study examines the association of cognitive ability in young adulthood with later use of benzodiazepines and explores whether the use of benzodiazepines during adult life is associated with cognitive decline in late midlife.

METHODS

The study samples include cognitive tests on the Børge Priens Prøve (BPP) from the conscription board examination (age 19 years) from 335 513 men born 1949-1961 and data from re-examinations of 5183 men 44 years later. Cognitive decline was defined as the difference between scores at the conscription board and the re-examination. Information on purchases of benzodiazepines was obtained from the Danish National Prescription Registry, 1995-2022. Associations were analysed using Cox proportional hazards and linear regression.

RESULTS

In total, 120 911 (36%) men purchased benzodiazepines during a follow-up of 20 years. Lower cognitive scores in young adulthood were associated with a higher risk of initiating benzodiazepines (hazard ratio [95% CI] = 0.71[0.68-0.75]). Men with the highest cumulative use of benzodiazepines had larger cognitive decline (β-coefficient [95% CI] = -1.66 [-2.09 to -1.23] BPP scores) compared with never users. Current benzodiazepine users showed a larger cognitive decline than never users (β-coefficient [95% CI] = -2.42[-3.18 to -1.66] BPP scores) and this partially explained the above association. These estimates for cognitive decline were relatively small and may lack clinical relevance.

CONCLUSION

Low cognitive ability increases the risk of benzodiazepine use in adulthood and cognitive decline is more pronounced in those with the highest benzodiazepine use compared with never-use, but the difference lacks clinical significance.

Impact of public health and patient-centered prevention strategies on periodontitis and caries as causes of tooth loss in high-income countries

In high-income countries, the oral health of the population is influenced by public health interventions, widespread use of oral care products, dental practice measures, and the cost of dental treatment. We compiled information on changes of the prevalence of proximal and upstream determinants of periodontitis, caries, and tooth loss over the last three decades to outline their potential effects on changes of oral health during this period. Information was retrieved from repeated cross-sectional studies and from published literature. While both the prevalence of edentulism and the number of missing teeth (from the DMF-T index) decreased, the number of sound teeth as well as the total number of teeth increased. The prevalence of severe periodontitis was unchanged, whereas the prevalence of periodontal health and moderate periodontitis may have increased to a minor extent. Concerning oral health risk factors, the proportion of individuals with tertiary education increased, while smoking prevalence declined. More and more people used oral care products. Whether one reimbursement system worked better than another one in terms of tooth retention could not be elucidated. In tooth retention, population-wide use of fluoridated toothpastes had the greatest impact. To some extent, the higher number of teeth present may be related to the more frequent use of interdental cleaning aids and powered toothbrushes. Since there was no decrease in severe periodontitis in most cohorts, periodontal interventions probably contributed little to improved tooth retention.

The Causal Relationships Between Gut Microbiota, Brain Volume, and Intelligence: A Two-Step Mendelian Randomization Analysis

BACKGROUND

Growing evidence indicates that dynamic changes in gut microbiome can affect intelligence; however, whether these relationships are causal remains elusive. We aimed to disentangle the poorly understood causal relationship between gut microbiota and intelligence.

METHODS

We performed a 2-sample Mendelian randomization (MR) analysis using genetic variants from the largest available genome-wide association studies of gut microbiota (N = 18,340) and intelligence (N = 269,867). The inverse-variance weighted method was used to conduct the MR analyses complemented by a range of sensitivity analyses to validate the robustness of the results. Considering the close relationship between brain volume and intelligence, we applied 2-step MR to evaluate whether the identified effect was mediated by regulating brain volume (N = 47,316).

RESULTS

We found a risk effect of the genus Oxalobacter on intelligence (odds ratio = 0.968 change in intelligence per standard deviation increase in taxa; 95% CI, 0.952-0.985; p = 1.88 × 10-4) and a protective effect of the genus Fusicatenibacter on intelligence (odds ratio = 1.053; 95% CI, 1.024-1.082; p = 3.03 × 10-4). The 2-step MR analysis further showed that the effect of genus Fusicatenibacter on intelligence was partially mediated by regulating brain volume, with a mediated proportion of 33.6% (95% CI, 6.8%-60.4%; p = .014).

CONCLUSIONS

Our results provide causal evidence indicating the role of the microbiome in intelligence. Our findings may help reshape our understanding of the microbiota-gut-brain axis and development of novel intervention approaches for preventing cognitive impairment.

Risk Factors for Natural Cause Mortality in Schizophrenia

Importance

Schizophrenia is associated with premature mortality from mostly natural causes. Decreased cognitive functioning has been identified as a determinant of mortality in the general population. However, there have been few prospective studies of this issue in persons with schizophrenia.

Objective

To examine whether lower cognitive functioning is a risk factor for natural cause mortality in schizophrenia.

Design, Setting, and Participants

This prospective cohort study included persons with schizophrenia or schizoaffective disorder enrolled between February 1, 1999, and December 31, 2022, at a nonprofit psychiatric system in Baltimore, Maryland. Participants were evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and other clinical measures.

Exposure

Natural cause mortality.

Main Outcomes and Measures

Associations of cognitive function, obesity, tobacco smoking, and medical conditions with natural cause mortality were evaluated using Cox proportional hazards regression models.

Results

Of the 844 participants enrolled (mean [SD] age, 39.6 [12.1] years; 533 male [63.2%]), 158 (18.7%) died of natural causes during a median follow-up of 14.4 years (range, 7.0 days to 23.9 years). The most significant factor associated with mortality was lower cognitive functioning as measured by the RBANS (Cox coefficient, -0.04; 95% CI, -0.05 to -0.03; z = -5.72; adjusted P < .001). Additional factors independently associated with mortality included the diagnosis of an autoimmune disorder (hazard ratio [HR], 2.86; 95% CI, 1.83-4.47; z = 4.62; adjusted P < .001), tobacco smoking (HR, 2.26; 95% CI, 1.55-3.30; z = 4.23; adjusted P < .001), diagnosis of chronic obstructive pulmonary disease (HR, 3.31; 95% CI, 1.69-6.49; z = 3.48; adjusted P = .006), body mass index as a continuous variable (HR, 1.06; 95% CI, 1.02-1.09; z = 3.30; adjusted P = .01), diagnosis of a cardiac rhythm disorder (HR, 2.56; 95% CI, 1.40-4.69; z = 3.06; adjusted P = .02), and being divorced or separated (HR, 1.80; 95% CI, 1.22-2.65; z = 2.97; adjusted P = .02). An RBANS score below the 50th percentile displayed a joint association with being a smoker, having an elevated body mass index, and having a diagnosis of an autoimmune or a cardiac rhythm disorder.

Conclusions and Relevance

In this prospective cohort study, lower cognitive functioning was a risk factor for natural cause mortality in schizophrenia. Efforts should be directed at methods to improve cognitive functioning, particularly among individuals with additional risk factors.

Ant colony optimization for parallel test assembly

Ant colony optimization (ACO) algorithms have previously been used to compile single short scales of psychological constructs. In the present article, we showcase the versatility of the ACO to construct multiple parallel short scales that adhere to several competing and interacting criteria simultaneously. Based on an initial pool of 120 knowledge items, we assembled three 12-item tests that (a) adequately cover the construct at the domain level, (b) follow a unidimensional measurement model, (c) allow reliable and (d) precise measurement of factual knowledge, and (e) are gender-fair. Moreover, we aligned the test characteristic and test information functions of the three tests to establish the equivalence of the tests. We cross-validated the assembled short scales and investigated their association with the full scale and covariates that were not included in the optimization procedure. Finally, we discuss potential extensions to metaheuristic test assembly and the equivalence of parallel knowledge tests in general.

Investigating the impact of poverty on mental illness in the UK Biobank using Mendelian randomization

It is unclear whether poverty and mental illness are causally related. Using UK Biobank and Psychiatric Genomic Consortium data, we examined evidence of causal links between poverty and nine mental illnesses (attention deficit and hyperactivity disorder (ADHD), anorexia nervosa, anxiety disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, obsessive-compulsive disorder, post-traumatic stress disorder and schizophrenia). We applied genomic structural equation modelling to derive a poverty common factor from household income, occupational income and social deprivation. Then, using Mendelian randomization, we found evidence that schizophrenia and ADHD causally contribute to poverty, while poverty contributes to major depressive disorder and schizophrenia but decreases the risk of anorexia nervosa. Poverty may also contribute to ADHD, albeit with uncertainty due to unbalanced pleiotropy. The effects of poverty were reduced by approximately 30% when we adjusted for cognitive ability. Further investigations of the bidirectional relationships between poverty and mental illness are warranted, as they may inform efforts to improve mental health for all.

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.

Life-Course Pathways to Exceptional Longevity: Evidence From the Lothian Birth Cohort of 1921

BACKGROUND

Longevity, a hallmark of successful aging, is a multifactorial trait with influences from birth onwards. However, limited evidence exists on the pathways linking diverse life-course exposures to longevity, especially within a single cohort.

METHODS

We investigated associations between life-course factors and longevity among community-dwelling adults aged 79 (N = 547) from the Lothian Birth Cohort 1921 with a mortality follow-up of 24 years. Cox proportional hazards and structural equation (path) models were used to explore how factors from early life (social class, childhood intelligence quotient [IQ], education), midlife (social class), and later life (health, lifestyle, psychosocial well-being), as well as sex, personality, and apolipoprotein E e4 status, influence survival time in days.

RESULTS

During follow-up (1999-2023), 538 participants (98%) died (mean age of death = 89.3 years) and 9 survived (mean age = 101.6 years). Factors associated with lower mortality risk in the multivariable Cox model were higher cognitive function (hazard ratio [HR] = 0.72; 95% confidence interval [CI]: 0.59-0.88), better physical function (HR = 0.61; 95% CI: 0.44-0.85), and greater physical activity (HR = 0.81; 95% CI: 0.71-0.92), while history of cancer was associated with higher mortality risk (HR = 1.84; 95% CI: 1.22-2.77). The life-course path model identified the same direct predictors, with additional contributions from female sex and nonsmoking status, to greater longevity. Early- and midlife factors (IQ, education, social class), and emotional stability, conscientiousness, and female sex, were indirectly and positively associated with survival trajectories via multiple dimensions of adult health.

CONCLUSIONS

In understanding why people live to very old ages it is necessary to consider factors from throughout the life course, and to include demographic, psychosocial, and health variables.

Height and cognitive assessments in a cohort of US schoolchildren, kindergarten through fifth grade

An oft-repeated finding in child development research is that height and cognitive ability are positively related. Much of this work is limited in its ability to track height and cognitive development over time, with key constraints being the availability of longitudinal data and measures of ability that are comparable over time. This study evaluates the associations between height and assessments of reading, math, and science in a representative sample of US schoolchildren followed from kindergarten through fifth grade. Associations between height and assessment scores at each grade level, and height-growth and changes in scores over grade levels, are examined. The results suggest modest associations between concurrent height and assessment scores at each grade level that are robust to socioeconomic and school controls. There is limited association between height-growth and assessment outcomes, which is shown only for females. There is also little indication that height or height-growth is associated with improvements in scores. The findings suggest a modest association between height and cognitive ability in contemporary US schoolchildren, being attributed mostly to growth before kindergarten. The findings are consistent with the view that social and biological forces in early-life facilitate both physical and cognitive development.

Visual impairment and cognitive performance: A nationwide study of 1.4 million adolescents

PURPOSE

Previous research highlights the adverse effects of visual impairment (VI) on academic achievement in children, yet its impact on cognitive performance among adolescents and young adults remains under-studied. Therefore, this investigation aimed to analyse this association in a nationwide sample of Israeli adolescents.

METHODS

A retrospective population-based cross-sectional study was conducted among 1,410,616 Israeli-born adolescents aged 16-19 years, who were assessed before mandatory military service between 1993 and 2017. The definition of VI was based on best-corrected visual acuity (BCVA) measurements using a standard Snellen chart. Adolescents with BCVA worse than 6/9 in either or both eyes were classified as having unilateral or bilateral VI, respectively. Cognitive performance was measured using the General Intelligence Score (GIS), based on a validated four-domain test. Relationships were analysed using regression models yielding adjusted odds ratios (ORs) for low (<-1 standard deviation [SD]) and high (≥1 SD) cognitive Z-scores.

RESULTS

Of 1,410,616 adolescents (56.1% men), 13,773 (1.0%) had unilateral and 3980 (0.3%) had bilateral VI. Unilateral VI was associated with adjusted ORs for low and high cognitive Z-scores of 1.24 (1.19-1.30) and 0.84 (0.80-0.89), respectively. ORs were accentuated for bilateral VI, reaching 1.62 (1.50-1.75) and 0.81 (0.74-0.90) for low and high cognitive Z-scores, respectively. Cognitive performance subscores mirrored these results, with the visual-spatial functioning subtest demonstrating the greatest effect size. These associations persisted in sub-analyses restricted to adolescents with amblyopia-related VI, mild VI and unimpaired health status.

CONCLUSIONS

Visual impairment, including mild and unilateral cases, is associated with reduced cognitive performance scores assessed in late adolescence. Further research is required to gain a comprehensive understanding of the dynamics underlying this relationship.

A Novel Approach to Measuring an Old Construct: Aligning the Conceptualisation and Operationalisation of Cognitive Flexibility

A successful adjustment to dynamic changes in one's environment requires contingent adaptive behaviour. Such behaviour is underpinned by cognitive flexibility, which conceptually is part of fluid intelligence. We argue, however, that conventional approaches to measuring fluid intelligence are insufficient in capturing cognitive flexibility. We address the discrepancy between conceptualisation and operationalisation by introducing two newly developed tasks that aim at capturing within-person processes of dealing with novelty. In an exploratory proof-of-concept study, the two flexibility tasks were administered to 307 university students, together with a battery of conventional measures of fluid intelligence. Participants also provided information about their Grade Point Averages obtained in high school and in their first year at university. We tested (1) whether an experimental manipulation of a requirement for cognitive inhibition resulted in systematic differences in difficulty, (2) whether these complexity differences reflect psychometrically differentiable effects, and (3) whether these newly developed flexibility tasks show incremental value in predicting success in the transition from high school to university over conventional operationalisations of fluid intelligence. Our findings support the notion that cognitive flexibility, when conceptualised and operationalised as individual differences in within-person processes of dealing with novelty, more appropriately reflects the dynamics of individuals' behaviour when attempting to cope with changing demands.

The Danish Aging and Cognition (DanACo) cohort

BACKGROUND

With aging populations worldwide, identification of predictors of age-related cognitive decline is becoming increasingly important. The Danish Aging and Cognition Cohort (DanACo) including more than 5000 Danish men was established to investigate predictors of age-related cognitive decline from young adulthood to late mid-life.

CONSTRUCTION AND CONTENT

The DanACo cohort was established through two separate data collections with identical designs involving a follow-up examination in late mid-life of men for whom intelligence test scores were available from their mandatory conscription board examination. The cohort consists of 5,183 men born from 1949 through 1961, with a mean age of 20.4 years at baseline and a mean age of 64.4 years at follow-up. The baseline measures consisted of height, weight, intelligence test score and educational level collected at the conscription board examination. The follow-up assessment consisted of a re-administration of the same intelligence test and a comprehensive questionnaire covering socio-demographic factors, lifestyle, and health-related factors. The data were collected in test sessions with up to 24 participants per session. Using the unique personal identification number assigned to all Danes, the cohort has been linked to data from national administrative and health registers for prospectively collected data on socioeconomic and health-related factors.

UTILITY AND DISCUSSION

The DanACo cohort has some major strengths compared to existing cognitive aging cohorts such as a large sample size (n = 5,183 men), a validated global measure of cognitive ability, a long retest interval (mean 44.0 years) and the availability of prospectively collected data from registries as well as comprehensive questionnaire data. The main weakness is the low participation rate (14.3%) and that the cohort consists of men only.

CONCLUSION

Cognitive decline is a result of a summary of factors across the life-course. The DanACo cohort is characterized by a long retest interval and contains data on a wealth of factors across adult life which is essential to establish evidence on predictors of cognitive decline. Moreover, the size of the cohort ensures sufficient statistical power to identify even relatively weak predictors of cognitive decline.

Independent associations of education, intelligence, and cognition with gastrointestinal diseases and the mediating effects of risk factors: a Mendelian randomization study

Background

Education, intelligence and cognition affect occupational performance and socioeconomic status and may influence virous diseases development. However, the impact of these factors on gastrointestinal diseases and their mediating risk factors remains unclear.

Methods

We utilized genome-wide association studies from European ancestry populations to perform two-sample Mendelian randomization analyses, aiming to estimate genetic instruments associated with education, intelligence, or cognition in relation to 24 gastrointestinal diseases Subsequently, we evaluated 14 potential mediators of this association and calculated the corresponding mediated proportions through two-step Mendelian randomization analyses.

Result

As the dominant factor in gastrointestinal diseases, education had a statistically significant association with 2 gastrointestinal diseases (acute pancreatitis, gastroesophageal reflux) and a suggestive association with 6 diseases (cirrhosis, alcoholic liver disease, cholecystitis, cholelithiasis, chronic gastritis and gastric ulcer). Of the 14 mediators, smoking and adiposity traits played a major role in mediating the effects.

Conclusion

The study demonstrated the causal, independent impact of education on specific gastrointestinal diseases. Smoking and adiposity traits emerged as primary mediators, illuminating potential avenues for targeted interventions for prevention of them.

The Big-Five personality factors, cognitive ability, health, and social-demographic indicators as independent predictors of self-efficacy: A longitudinal study

This study set out to examine to what extent a set of psychological, health and socio-demographic factors are associated with self-efficacy (SE) in a large sample of over 12,000 participants over a two-year period. We were interested in the correlates of self-efficacy (criterion variable) with gender, age, education and occupation, the Big-Five personality factors and cognitive ability, as well as mental and physical health (predictor variables). Regression analyses showed that four of the Big-Five personality factors (extraversion, neuroticism, conscientiousness, and openness), cognitive ability, mental and physical health, gender, education and occupation were all significant and independent predictors of self-efficacy, accounting for 23% of the variance of the outcome variable. Personality variables, particularly Neuroticism and Conscientiousness, were the most powerful predictors of SE two years later. The implications for encouraging SE in individuals are discussed.

Adolescent Body Mass Index and Early Chronic Kidney Disease in Young Adulthood

IMPORTANCE

Despite increasing obesity rates in adolescents, data regarding early kidney sequelae are lacking.

OBJECTIVE

To assess the association between adolescent body mass index (BMI) and early chronic kidney disease (CKD) in young adulthood (<45 years of age).

DESIGN, SETTING, AND PARTICIPANTS

This cohort study linked screening data of mandatory medical assessments of Israeli adolescents to data from a CKD registry of a national health care system. Adolescents who were aged 16 to 20 years; born since January 1, 1975; medically evaluated for mandatory military service through December 31, 2019; and insured by Maccabi Healthcare Services were assessed. Individuals with kidney pathology, albuminuria, hypertension, dysglycemia, or missing blood pressure or BMI data were excluded. Body mass index was calculated as weight in kilograms divided by height in meters squared and categorized by age- and sex-matched percentiles according to the US Centers for Disease Control and Prevention. Follow-up started at the time of medical evaluation or January 1, 2000 (whichever came last), and ended at early CKD onset, death, the last day insured, or August 23, 2020 (whichever came first). Data analysis was performed from December 19, 2021, to September 11, 2023.

MAIN OUTCOMES AND MEASURES

Early CKD, defined as stage 1 to 2 CKD by moderately or severely increased albuminuria, with an estimated glomerular filtration rate of 60 mL/min/1.73 m2 or higher.

RESULTS

Of 629 168 adolescents evaluated, 593 660 (mean [SD] age at study entry, 17.2 [0.5] years; 323 293 [54.5%] male, 270 367 [45.5%] female) were included in the analysis. During a mean (SD) follow-up of 13.4 (5.5) years for males and 13.4 (5.6) years for females, 1963 adolescents (0.3%) developed early CKD. Among males, the adjusted hazard ratios were 1.8 (95% CI, 1.5-2.2) for adolescents with high-normal BMI, 4.0 (95% CI, 3.3-5.0) for those with overweight, 6.7 (95% CI, 5.4-8.4) for those with mild obesity, and 9.4 (95% CI, 6.6-13.5) for those with severe obesity. Among females, the hazard ratios were 1.4 (95% CI, 1.2-1.6) for those with high-normal BMI, 2.3 (95% CI, 1.9-2.8) for those with overweight, 2.7 (95% CI, 2.1-3.6) for those with mild obesity, and 4.3 (95% CI, 2.8-6.5) for those with severe obesity. The results were similar when the cohort was limited to individuals who were seemingly healthy as adolescents, individuals surveyed up to 30 years of age, or those free of diabetes and hypertension at the end of the follow-up.

CONCLUSIONS AND RELEVANCE

In this cohort study, high BMI in late adolescence was associated with early CKD in young adulthood. The risk was also present in seemingly healthy individuals with high-normal BMI and before 30 years of age, and a greater risk was seen among those with severe obesity. These findings underscore the importance of mitigating adolescent obesity rates and managing risk factors for kidney disease in adolescents with high BMI.

On some challenges of psychological research in late adulthood and aging

The World population is aging and, consequently, understanding late adulthood and aging processes is a major scientific priority. Research in this segment of the life is particularly challenging: the lifespan approach, necessary for thorough aging investigations, implies theoretical multidisciplinary and methodological multivariate perspectives; variability during aging is particularly high compared to previous life phases; study designs must account for specific predicaments (such as confound between age, cohort, and time of measurement; selective study participation and attrition; assumed age-invariance of measurements; retest effects). Furthermore, promising methods for data analysis develop on a daily basis, requiring continuous technical training. I will discuss some of these challenges, summarize extant potential solutions, and touch on some ethical and broader social responsibility issues.

Aging Brain from a Lifespan Perspective

Research during the last two decades has shown that the brain undergoes continuous changes throughout life, with substantial heterogeneity in age trajectories between regions. Especially, temporal and prefrontal cortices show large changes, and these correlate modestly with changes in the corresponding cognitive abilities such as episodic memory and executive function. Changes seen in normal aging overlap with changes seen in neurodegenerative conditions such as Alzheimer's disease; differences between what reflects normal aging vs. a disease-related change are often blurry. This calls for a dimensional view on cognitive decline in aging, where clear-cut distinctions between normality and pathology cannot be always drawn. Although much progress has been made in describing typical patterns of age-related changes in the brain, identifying risk and protective factors, and mapping cognitive correlates, there are still limits to our knowledge that should be addressed by future research. We need more longitudinal studies following the same participants over longer time intervals with cognitive testing and brain imaging, and an increased focus on the representativeness vs. selection bias in neuroimaging research of aging.

Blepharoptosis and cognitive performance: a population-based study of 1.4 million adolescents

The purpose of this study is to examine the association between blepharoptosis and cognitive performance in late adolescence. This population-based, retrospective, cross-sectional study included 1,411,570 Israeli-born adolescents (620,107 women, 43.9%) aged 16-19 years who were medically examined before compulsory military service between 1993 and 2017. The diagnosis of blepharoptosis was verified by an ophthalmologist. Cognitive performance was assessed by a validated intelligence-quotient-equivalent test, comprising four domains (problem-solving, verbal abstraction and categorization, verbal comprehension, and mathematical abilities). Cognitive Z-scores were calculated and categorized as high (≥ 1 standard deviation (SD)), medium (- 1 to < 1 SD), and low (less than - 1 SD). Relationships were analyzed using regression models adjusted for sociodemographic variables including sex, year of birth, residential socioeconomic status, education level, body mass index, and familial country of origin. A total of 577 (41 per 100,000, 32.2% women) adolescents were diagnosed with blepharoptosis. The proportions of unilateral and bilateral visual impairment among adolescents with blepharoptosis were 13.0% and 3.5%, respectively. In a multivariable analysis, blepharoptosis was associated with a 0.18 SD reduction in cognitive Z-score (p < 0.001). The adjusted odds ratios for low and high cognitive Z-scores in adolescents with blepharoptosis were 1.54 (1.25-1.89) and 0.80 (0.62-1.04), respectively. This relationship persisted when adolescents with normal best-corrected visual acuity or unimpaired health status were analyzed separately.  Conclusions: Blepharoptosis is associated with reduced cognitive performance determined in late adolescence. Future prospective studies should investigate the causes of this link and their underlying mechanisms. What is Known: • While earlier investigations have examined the effects of blepharoptosis on vision and quality of life, the association between blepharoptosis and cognitive outcomes in youth has remained unexplored. What is New: • This nationwide study involving 1.4 million Israeli adolescents found a correlation between blepharoptosis and reduced cognitive performance. • Our findings suggest a potential interplay between blepharoptosis and cognitive development in the pediatric population, calling for increased focus on the educational needs of affected individuals.

Cognition in older adults in Uganda: Correlates, trends over time and association with mortality in prospective population study

Dementia is an important and growing issue in sub-Saharan Africa, but epidemiological data are lacking. Risk factors may differ from other regions due to high stroke incidence and HIV prevalence. Understanding the epidemiology of cognition in older adults in Africa is crucial for informing public health strategies to improve the lives of people with dementia and their carers. The Wellbeing of Older People Study in Uganda is an open cohort of adults aged 50+ with and without HIV, established in 2009. Detailed socio-demographic and health data have been collected at four waves spanning 10 years, including cognitive assessment using internationally validated WHO-recommended tests: verbal recall, digit span, and verbal fluency. Mortality data was collected until the end of the fourth wave (2019). We examined associations of low baseline cognition scores and changes in cognition score over time using random effects modelling, care needs of people with lower cognition scores, and the relationship between cognition score and mortality. Data were collected on 811 participants. Older age, lower educational attainment, lower socio-economic position, and extremes of BMI were associated with lower cognition scores. Cognition scores declined faster at older ages, but rate of decline was not associated with cardiovascular disease or HIV at baseline. People with lower cognition scores required more assistance with Activities of Daily Living, but mortality rates were similar across the range of cognition scores. The crucial next step will be to investigate types and presentation of clinical dementia in this cohort, so we can better understand the clinical relevance of these findings to inform public health planning.

Timing of lifespan influences on brain and cognition

Modifiable risk and protective factors for boosting brain and cognitive development and preventing neurodegeneration and cognitive decline are embraced in neuroimaging studies. We call for sobriety regarding the timing and quantity of such influences on brain and cognition. Individual differences in the level of brain and cognition, many of which present already at birth and early in development, appear stable, larger, and more pervasive than differences in change across the lifespan. Incorporating early-life factors, including genetics, and investigating both level and change will reduce the risk of ascribing undue importance and causality to proximate factors in adulthood and older age. This has implications for both mechanistic understanding and prevention.

Multivariate prediction of cognitive performance from the sleep electroencephalogram

Human cognitive performance is a key function whose biological foundations have been partially revealed by genetic and brain imaging studies. The sleep electroencephalogram (EEG) is tightly linked to structural and functional features of the central nervous system and serves as another promising biomarker. We used data from MrOS, a large cohort of older men and cross-validated regularized regression to link sleep EEG features to cognitive performance in cross-sectional analyses. In independent validation samples 2.5-10% of variance in cognitive performance can be accounted for by sleep EEG features, depending on the covariates used. Demographic characteristics account for more covariance between sleep EEG and cognition than health variables, and consequently reduce this association by a greater degree, but even with the strictest covariate sets a statistically significant association is present. Sigma power in NREM and beta power in REM sleep were associated with better cognitive performance, while theta power in REM sleep was associated with worse performance, with no substantial effect of coherence and other sleep EEG metrics. Our findings show that cognitive performance is associated with the sleep EEG (r = 0.283), with the strongest effect ascribed to spindle-frequency activity. This association becomes weaker after adjusting for demographic (r = 0.186) and health variables (r = 0.155), but its resilience to covariate inclusion suggest that it also partially reflects trait-like differences in cognitive ability.

Cognitive ability, health policy, and the dynamics of COVID-19 vaccination

We examine the relationship between cognitive ability and prompt COVID-19 vaccination using individual-level data on more than 700,000 individuals in Sweden. We find a strong positive association between cognitive ability and swift vaccination, which remains even after controlling for confounding variables with a twin-design. The results suggest that the complexity of the vaccination decision may make it difficult for individuals with lower cognitive abilities to understand the benefits of vaccination. Consistent with this, we show that simplifying the vaccination decision through pre-booked vaccination appointments alleviates almost all of the inequality in vaccination behavior.

Multivariate genetic analysis of personality and cognitive traits reveals abundant pleiotropy

Personality and cognitive function are heritable mental traits whose genetic foundations may be distributed across interconnected brain functions. Previous studies have typically treated these complex mental traits as distinct constructs. We applied the 'pleiotropy-informed' multivariate omnibus statistical test to genome-wide association studies of 35 measures of neuroticism and cognitive function from the UK Biobank (n = 336,993). We identified 431 significantly associated genetic loci with evidence of abundant shared genetic associations, across personality and cognitive function domains. Functional characterization implicated genes with significant tissue-specific expression in all tested brain tissues and brain-specific gene sets. We conditioned independent genome-wide association studies of the Big 5 personality traits and cognitive function on our multivariate findings, boosting genetic discovery in other personality traits and improving polygenic prediction. These findings advance our understanding of the polygenic architecture of these complex mental traits, indicating a prominence of pleiotropic genetic effects across higher order domains of mental function such as personality and cognitive function.

Association of Birth Weight Centiles and Gestational Age With Cognitive Performance at Age 5 Years

Importance

Birth weight percentiles (BWPs) are often dichotomized at the 10th percentile and show statistically significant association with later cognitive performance, for both preterm and term-born children. However, research testing nonlinear associations between BWPs and cognitive performance is scarce.

Objective

To investigate culturally invariant, nonlinear associations of BWPs and gestational age with later cognitive performance.

Design, Setting, and Participants

In this cohort study, participants with valid neonatal and cognitive data were combined from 4 observational cohorts, including the Millennium Cohort Study, the National Longitudinal Survey of Youth 1979 Child and Young Adult cohort, Growing Up in Ireland, and the Longitudinal Study of Australian Children, with children born between 2000 and 2002, 1980 and 2010, 2007 and 2008, and 2003 and 2004, respectively. Neonatal data were parent reported before age 1 year. At approximately 5 years of age, multiple cognitive tests were performed. Follow-up at 5 years of age was the predominant focus. Data were analyzed July 17, 2023.

Exposure

The parent-reported neonatal data were used to calculate BWPs according to the Fenton growth chart.

Main Outcome and Measure

Scores for IQ were created from multiple measures of cognition, which were z standardized separately within each cohort.

Results

Of 30 643 participants (50.8% male), 7.5% were born preterm (before 37 weeks gestation) and 92.5% were term born (between 37 and 42 weeks gestation). In the pooled data using multivariate adaptive regression splines, IQ linearly increased by 4.2 points as BWPs increased from the first to the 69th percentile before completely plateauing. For gestational age, IQ linearly increased by 1.3 points per week up until 32 weeks, with the association reducing to 0.3 points per week after 32 weeks. The association of BWP with IQ was not moderated by gestational age. For term-born infants, the estimated IQ score was only clinically meaningfully lower than average when birth weight was below the third percentile. Consistent results were found when instead using multivariable regression where gestational age and BWPs were categorized into groups.

Conclusions and Relevance

In this cohort study, lower BWPs and gestational age were independently associated with lower IQ. For term-born infants, a cutoff of the third percentile would be more appropriate than the traditionally used 10th percentile when the aim is estimating meaningful cognitive differences.

Adolescent body mass index and cognitive performance: a nationwide study of 2.48 million Israeli adolescents

IMPORTANCE

The increased incidence of adolescent obesity over recent decades may be associated with lower cognitive performance than the expected potential.

OBJECTIVE

We aimed to assess the association between adolescent body mass index (BMI) and cognitive function.

DESIGN

A nationwide, cross-sectional, population-based study.

SETTING

Pre-recruitment evaluation for military service during 1967-2018.

PARTICIPANTS

All Israeli-born adolescents, 1 459 522 males and 1 027 953 females aged 16 to ≤20 years.

EXPOSURES

Weight and height were measured to calculate BMI.

MAIN OUTCOME

Cognitive performance was assessed by using a validated intelligence-quotient-equivalent test and was standardized to the year- and sex-Z-score. For 445 385 persons, parental cognitive scores could be identified. Multinomial logistic regression models were applied.

RESULTS

Among male adolescents with severe obesity, 29.4% achieved a cognitive score below the 25th percentile, compared with 17.7% among their normal-weight (50th-84th percentile) counterparts. A J-shaped relation was observed between BMI and the odds ratio (OR) for a low cognitive score among male adolescents: underweight, 1.45 (1.43-1.48); overweight, 1.13 (1.12-1.15); mild obesity, 1.36 (1.33-1.39); and severe obesity, 1.58 (1.52-1.64). Similar findings were observed in females. For both sexes, point estimates were overall consistent in models adjusted for sociodemographic confounders, coexisting morbidities, and parental cognitive scores. Examinees with abnormal BMI had higher ORs for a lower-than-expected cognitive score, based on their parents' data as adolescents, in a manner that depends on obesity severity.

CONCLUSION AND RELEVANCE

Obesity, is associated with increased odds for a lower cognitive performance, and the inability to fully achieve cognitive potential, regardless of sociodemographic background.

A review of the cognitive impact of neurodevelopmental and neuropsychiatric associated copy number variants

The heritability of intelligence or general cognitive ability is estimated at 41% and 66% in children and adults respectively. Many rare copy number variants are associated with neurodevelopmental and neuropsychiatric conditions (ND-CNV), including schizophrenia and autism spectrum disorders, and may contribute to the observed variability in cognitive ability. Here, we reviewed studies of intelligence quotient or cognitive function in ND-CNV carriers, from both general population and clinical cohorts, to understand the cognitive impact of ND-CNV in both contexts and identify potential genotype-specific cognitive phenotypes. We reviewed aggregate studies of sets ND-CNV broadly linked to neurodevelopmental and neuropsychiatric conditions, and genotype-first studies of a subset of 12 ND-CNV robustly associated with schizophrenia and autism. Cognitive impacts were observed across ND-CNV in both general population and clinical cohorts, with reports of phenotypic heterogeneity. Evidence for ND-CNV-specific impacts were limited by a small number of studies and samples sizes. A comprehensive understanding of the cognitive impact of ND-CNVs would be clinically informative and could identify potential educational needs for ND-CNV carriers. This could improve genetic counselling for families impacted by ND-CNV, and clinical outcomes for those with complex needs.

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.

Age of First Overweight and Obesity, COVID-19 and Long COVID in Two British Birth Cohorts

Longer exposure to obesity, and thus a longer period in an inflamed state, may increase susceptibility to infectious diseases and worsen severity. Previous cross-sectional work finds higher BMI is related to worse COVID-19 outcomes, but less is known about associations with BMI across adulthood. To examine this, we used body mass index (BMI) collected through adulthood in the 1958 National Child Development Study (NCDS) and the 1970 British Cohort Study (BCS70). Participants were grouped by the age they were first overweight (> 25 kg/m²) and obese (> 30 kg/m²). Logistic regression was used to assess associations with COVID-19 (self-reported and serology-confirmed), severity (hospital admission and contact with health services) and long-COVID reported at ages 62 (NCDS) and 50 (BCS70). An earlier age of obesity and overweight, compared to those who never became obese or overweight, was associated with increased odds of adverse COVID-19 outcomes, but results were mixed and often underpowered. Those with early exposure to obesity were over twice as likely in NCDS (odds ratio (OR) 2.15, 95% confidence interval (CI) 1.17-4.00) and three times as likely in BCS70 (OR 3.01, 95% CI 1.74-5.22) to have long COVID. In NCDS they were also over four times as likely to be admitted to hospital (OR 4.69, 95% CI 1.64-13.39). Most associations were somewhat explained by contemporaneous BMI or reported health, diabetes or hypertension; however, the association with hospital admission in NCDS remained. An earlier age of obesity onset is related to COVID-19 outcomes in later life, providing evidence of the long-term impact of raised BMI on infectious disease outcomes in midlife.

Independent Associations of Education, Intelligence, and Cognition With Hypertension and the Mediating Effects of Cardiometabolic Risk Factors: A Mendelian Randomization Study

BACKGROUND

Education, intelligence, and cognition are associated with hypertension, but which one plays the most prominent role in the pathogenesis of hypertension and which modifiable risk factors mediate the causal effects remains unknown.

METHODS

Using summary statistics of genome-wide association studies of predominantly European ancestry, we conducted 2-sample multivariable Mendelian randomization to estimate the independent effects of education, intelligence, or cognition on hypertension (FinnGen study, 70 651 cases/223 663 controls; UK Biobank, 77 723 cases/330 366 controls) and blood pressure (International Consortium of Blood Pressure, 757 601 participants), and used 2-step Mendelian randomization to evaluate 25 potential mediators of the association and calculate the mediated proportions.

RESULTS

Meta-analysis of inverse variance weighted Mendelian randomization results from FinnGen and UK Biobank showed that genetically predicted 1-SD (4.2 years) higher education was associated with 44% (95% CI: 0.40-0.79) decreased hypertension risk and 1.682 mm Hg lower systolic and 0.898 mm Hg lower diastolic blood pressure, independently of intelligence and cognition. While the causal effects of intelligence and cognition on hypertension were not independent of education; 6 out of 25 cardiometabolic risk factors were identified as mediators of the association between education and hypertension, ranked by mediated proportions, including body mass index (mediated proportion: 30.1%), waist-to-hip ratio (22.8%), body fat percentage (14.1%), major depression (7.0%), high-density lipoprotein cholesterol (4.7%), and triglycerides (3.4%). These results were robust to sensitivity analyses.

CONCLUSIONS

Our findings illustrated the causal, independent impact of education on hypertension and blood pressure and outlined cardiometabolic mediators as priority targets for prevention of hypertension attributable to low education.

Bright, but allergic and neurotic? A critical investigation of the "overexcitable genius" hypothesis

Introduction

Higher intelligence has been associated with improved health and longevity. However, recent findings have claimed that exceptional intelligence may come at a cost. Individuals at the upmost end of the intelligence distribution are reported to be disproportionately afflicted by a set of stress-related physical and mental health conditions: so-called overexcitabilities. Few accounts have investigated this issue and no studies are available for non-US samples yet. Here, we aimed to replicate and extend previous work by examining hitherto unaddressed overexcitabilities in a European high-IQ sample.

Methods

We carried out a preregistered survey among members of MENSA, the world's largest high-IQ society. In total, 615 (307 male) members from Austria, Germany, Hungary, Switzerland, and the United Kingdom participated.

Results and Discussion

Compared to the general population, our sample exhibited considerably elevated prevalences in autism spectrum disorders (risk ratio/RR = 2.25), chronic fatigue syndrome (RR = 5.69), depression (RR = 4.38), generalized anxiety (RR = 3.82), and irritable bowel syndrome (RR = 3.76). Contrary to previous accounts, neither asthma, allergies, nor autoimmune diseases were elevated. We show that this subsample of intellectually gifted persons faces specific health challenges compared to the general population. The reasons for this remain speculative, as we find little evidence for previously proposed immunological explanations. However, it is possible that the effects are caused by sample selectiveness (i.e., membership in a high-IQ society) rather than high IQ itself.

Is There a "Gifted Personality"? Initial Evidence for Differences between MENSA and General Population Members in the HEXACO Personality Inventory

Contrary to the common notion that personality and intelligence are unrelated constructs, numerous correlational studies have demonstrated substantial associations between the two domains. Moreover, samples of intellectually gifted individuals have been found to differ from the general population in specific aspects of their personalities. However, most studies so far have relied on the Five-Factor Model of Personality (FFM), while none have investigated this phenomenon using the HEXACO personality framework. We recruited 617 adult members of the international high-IQ society MENSA and compared them to 3 reference samples (combined N = 112,637) regarding their personalities as measured by the HEXACO-60 personality inventory. We found that gifted persons scored higher in Honesty-Humility and Conscientiousness but lower in Emotionality compared to reference samples. Interestingly, gifted individuals scored only slightly higher in Openness to Experience, and no consistent differences emerged for Agreeableness. We demonstrate that some known personality differences between gifted and non-gifted persons translate from the FFM to the HEXACO model, while others do not. Our results indicate that within the HEXACO factor structure differences in sociability are more pronounced, while intellect-related differences are comparatively weak.

Brain aging differs with cognitive ability regardless of education

Higher general cognitive ability (GCA) is associated with lower risk of neurodegenerative disorders, but neural mechanisms are unknown. GCA could be associated with more cortical tissue, from young age, i.e. brain reserve, or less cortical atrophy in adulthood, i.e. brain maintenance. Controlling for education, we investigated the relative association of GCA with reserve and maintenance of cortical volume, -area and -thickness through the adult lifespan, using multiple longitudinal cognitively healthy brain imaging cohorts (n = 3327, 7002 MRI scans, baseline age 20-88 years, followed-up for up to 11 years). There were widespread positive relationships between GCA and cortical characteristics (level-level associations). In select regions, higher baseline GCA was associated with less atrophy over time (level-change associations). Relationships remained when controlling for polygenic scores for both GCA and education. Our findings suggest that higher GCA is associated with cortical volumes by both brain reserve and -maintenance mechanisms through the adult lifespan.

Novel Indices of Cognitive Impairment and Incident Cardiovascular Outcomes in the REWIND Trial

CONTEXT

Low cognitive scores are risk factors for cardiovascular outcomes. Whether this relationship is stronger using novel cognitive indices is unknown.

METHODS

Participants in the Researching Cardiovascular Events with a Weekly Incretin in Diabetes (REWIND) trial who completed both the Montreal Cognitive Assessment (MoCA) score and Digit Substitution Test (DSST) at baseline (N = 8772) were included. These scores were used to identify participants with baseline substantive cognitive impairment (SCI), defined as a baseline score on either the MoCA or DSST ≥ 1.5 SD below either score's country-specific mean, or SCI-GM, which was based on a composite index of both scores calculated as their geometric mean (GM), and defined as a score that was ≥ 1.5 SD below their country's average GM. Relationships between these measures and incident major adverse cardiovascular events (MACE), and either stroke or death were analyzed.

RESULTS

Compared with 7867 (89.7%) unaffected participants, the 905 (10.3%) participants with baseline SCI had a higher incidence of MACE (unadjusted hazard ratio [HR] 1.34; 95% CI 1.11, 1.62; P = 0.003), and stroke or death (unadjusted HR 1.60; 95% CI 1.33, 1.91; P < 0.001). Stronger relationships were noted for SCI-GM and MACE (unadjusted HR 1.61; 95% CI 1.28, 2.01; P < 0.001), and stroke or death (unadjusted HR 1.85; 95% CI 1.50, 2.30; P < 0.001). For SCI-GM but not SCI, all these relationships remained significant in models that adjusted for up to 10 SCI risk factors.

CONCLUSION

Country-standardized SCI-GM was a strong independent predictor of cardiovascular events in people with type 2 diabetes in the REWIND trial.

Wrecked by Success? Not to Worry

We examined the wrecked-by-success hypothesis. Initially formalized by Sigmund Freud, this hypothesis has become pervasive throughout the humanities, popular press, and modern scientific literature. The hypothesis implies that truly outstanding occupational success often exacts a heavy toll on psychological, interpersonal, and physical well-being. Study 1 tested this hypothesis in three cohorts of 1,826 high-potential, intellectually gifted individuals. Participants with exceptionally successful careers were compared with those of their gender-equivalent intellectual peers with more typical careers on well-known measures of psychological well-being, flourishing, core self-evaluations, and medical maladies. Family relationships, comfort with aging, and life satisfaction were also assessed. Across all three cohorts, those deemed occupationally outstanding individuals were similar to or healthier than their intellectual peers across these metrics. Study 2 served as a constructive replication of Study 1 but used a different high-potential sample: 496 elite science/technology/engineering/mathematics (STEM) doctoral students identified in 1992 and longitudinally tracked for 25 years. Study 2 replicated the findings from Study 1 in all important respects. Both studies found that exceptionally successful careers were not associated with medical frailty, psychological maladjustment, and compromised interpersonal and family relationships; if anything, overall, people with exceptionally successful careers were medically and psychologically better off.

Education and Literacy as Risk Factors of Dementia after Stroke and Transient Ischemic Attack: NEDICES Study

Background: A protective effect of education on cognitive decline after stroke has been claimed, but evidence from prospective population-based cohorts is very limited. The differential role of literacy and education on dementia after stroke remains unexplored. Objective: This research addresses the role of education and literacy in dementia incidence after stroke and transient ischemic attack (TIA). Methods: 131 participants with stroke or TIA were identified within the population-based NEDICES study (N = 5,278 persons). Participants were fully assessed at baseline (1994–1995) and incident dementia diagnosis was made by expert neurologists (DSM-IV criteria) after a mean follow-up of 3.4 years. Adjusted Cox regression analyses were applied to test the association between education, literacy, and dementia risk. Results: Within the 131 subjects with stroke or TIA, 19 (14%) developed dementia at follow-up. The Cox’s regression model (age and sex adjusted) showed that low education (HR = 3.48, 95% CI = 1.28, 9.42, p = 0.014) and literacy (HR = 3.16, 95% CI = 1.08, 9.22, p = 0.035) were significantly associated with a higher dementia risk. Low education was also associated with dementia when main confounders (i.e., cognitive/functional performance) were considered in the Cox’s model. However, after including stroke recurrence, only low/null literacy (versus education) remained as significant predictor of dementia. Finally, low/null literacy showed an effect over-and-above education on dementia risk when both factors were introduced in the adjusted Cox’s regression. Conclusion: These findings underline the importance of literacy to estimate cognitive decline after stroke in low-educated populations.

Subjective Socioeconomic Status, Cognitive Abilities, and Personal Control: Associations With Health Behaviours

Objective

To examine subjective and objective socioeconomic status (SSES and OSES, respectively) as predictors, cognitive abilities as confounders, and personal control perceptions as mediators of health behaviours.

Design

A cross-sectional study including 197 participants aged 30–50 years, recruited from the crowd-working platform, Prolific.

Main Outcome Measure

The Good Health Practices Scale, a 16-item inventory of health behaviours.

Results

SSES was the most important predictor of health behaviours (beta = 0.19, p &lt; 0.01). Among the OSES indicators, education (beta = 0.16, p &lt; 0.05), but not income, predicted health behaviours. Intelligence (r = −0.16, p &lt; 0.05) and memory (r = −0.22, p &lt; 0.01) were negatively correlated with health-promoting behaviours, and the effect of memory was upheld in the multivariate model (beta = −0.17, p &lt; 0.05). Personal control perceptions (mastery and constraints) did not act as mediators.

Conclusion

SSES predicted health behaviours beyond OSES. The effect of socioeconomic indicators was not confounded by cognitive abilities. Surprisingly, cognitive abilities were negatively associated with health-promoting behaviours. Future research should emphasise SSES as a predictor of health behaviours. Delineating the psychological mechanisms linking SSES with health behaviours would be a valuable contribution toward improved understanding of socioeconomic disparities in health behaviours.

Understanding the consequences of educational inequalities on periodontitis: Mendelian randomization study

AIM

Higher educational attainment is associated with a lower risk of periodontitis, but the extent to which this association is causal and mediated by intermediate factors is unclear.

METHODS AND MATERIALS

Using summary data from genetic association studies from up to 1.1 million participants of European descent, univariable and multivariable Mendelian randomization analyses were performed to infer the total effect of educational attainment on periodontitis and to estimate the degree to which income, smoking, alcohol consumption, and body mass index mediate the association.

RESULTS

The odds ratio of periodontitis per one standard deviation increment in genetically predicted education was 0.78 (95% CI: 0.68-0.89). The proportions mediated of the total effect of genetically predicted education on periodontitis were 64%, 35%, 15%, and 46% for income, smoking, alcohol consumption, and body mass index, respectively.

CONCLUSIONS

Using a genetic instrumental variable approach, this study triangulated evidence from existing observational epidemiological studies and suggested that higher educational attainment lowers periodontitis risk. Measures to reduce the burden of educational disparities in periodontitis risk may tackle downstream risk factors, particularly income, smoking, and obesity.

Adolescent cognitive function and incident early-onset type 2 diabetes

BACKGROUND

Cognitive function among apparently healthy adolescents has been associated with cardiovascular morbidity and mortality. We examined the relationship between global and subdomain cognitive scores in adolescence and early-onset type 2 diabetes (T2D) in men and women.

METHODS

A nationwide, population-based study of 971,677 Israeli born adolescents (56% men; mean age 17.4 years) who were medically examined and their cognitive performance was assessed before compulsory military service during 1992-2010. Data included global and subdomain cognitive Z-scores (problem-solving, verbal abstraction and categorization, verbal comprehension, and mathematical abilities). Data were linked to the Israeli National Diabetes Registry. The relations between global and subdomain scores and incident T2D was determined using Cox proportional hazard models and logistic regression models. Analyses were conducted separately for men and women.

FINDINGS

During 16,095,122 person-years, 3,570 individuals developed T2D. After adjustment, those in the low compared to the high quintile of global cognitive Z-score had the highest risk for T2D; HR 2.46, (95% CI 2.10-2.88) for men and 2.33 (95% CI 1.88-2.89) for women. A one-unit lower global cognitive Z-score was associated with 1.41 (95% CI 1.34-1.48) and 1.46 (95% CI 1.36-1.56) increased risks for men and women, respectively. The relationship was noted for the cognitive subdomains scores as well as for the global cognitive score, with no heterogeneity across cognitive subdomains.

INTERPRETATION

This large nationally representative cohort suggests relationship between global, as well as subdomain cognitive scores in late adolescence, and incident early onset T2D in both sexes, which was independent of socioeconomic status.