Intelligence: is it the epidemiologists' elusive "fundamental cause" of social class inequalities in health?

Why don't Chinese college students seek help from the National Health Service (NHS)? Chinese college students' use of medical services in the UK

Background

International students have a lower utilization rate of the local medical service system for studying abroad, and it has been found that there may be multiple reasons behind this phenomenon. This study explores the usage of medical service systems by international students and the underlying logical factors through a study of the usage of National Health Service (NHS) of Chinese students in the UK.

Methods

To address the research questions, this study employed an online survey methodology that ran between 1st May and August 20, 2019 facing the Chinese students in the UK. A total of 1,050 questionnaires were distributed and 1,001 questionnaires were recovered, of which 977 contained valid responses (questionnaire response rate was 95.3 % and validity rate was 97.6 %). Before the questionnaire was designed and after it was issued, two focus group interviews were conducted to provide reliable and detailed information to inform the questionnaire design and to supplement the questionnaire survey data with more profound psychological qualitative data. The two focus groups consisted of 10 and 12 Chinese students studying in the UK and each lasted more than 3 h.

Results

The survey data showed that the medical services utilization rate of Chinese students in the UK is relatively low compared to UK residents and domestic Chinese students. Their decisions and behaviours around medical services usage in the UK are not significantly related to age, gender, and monthly income, but are instead related to their current education status, types of disease suffered, and information acquisition about the UK medical services before coming to the UK. When getting sick, in addition to seeking help from official medical services, Chinese students studying in the UK tend to self-diagnose and self-medicate; seeking help from social networks based on friendship and domestic relatives are also alternatives to accessing medical services.

Conclusion

Combining the theories of 'sick role' and 'illness experience', the decisions and behaviours related to medical services usage by Chinese students in the UK are significantly influenced by their understanding of medical services, which is socially and culturally learned in China. Understanding the perspective of the 'sick role' and the 'illness experience' of Chinese students may help to better think about how improvements can be made to their utilization rate of medical services and their health status during their studies in the UK. This study not only provides us with specific information and understanding on the usage of medical services for Chinese students in the UK, but the research results may also provide a reference for other similar research on the health and medical service use of other international students studying in the cross-cultural contexts.

A growing divide: Trends in social inequalities in healthy longevity in Australia, 2001-20

This study examines two decades of change in social inequalities in life and health expectancy among older adults in Australia, one of the few countries that escaped an economic recession during the global financial crisis. We compare adults aged 45+ across three measures of individual socio-economic position-education, occupation, and household wealth-and use multistate life tables to estimate total life expectancy (TLE) and life expectancy free of limiting long-term illness (LLTI-free LE) based on 20 waves of the Household, Income and Labour Dynamics in Australia Survey (2001-20). Our findings highlight substantial social disparities in both TLE and LLTI-free LE in Australia. Grouping individuals by household wealth shows striking differentials in LLTI-free LE. We observe widening social disparities in healthy longevity over time by all three measures of socio-economic position. This diverging trend in healthy longevity is troubling against the backdrop of widening income and wealth inequalities in Australia.

Midlife diseases of despair and cardiometabolic risk: testing shared origins in adolescent psychopathology

BACKGROUND

Rising midlife mortality in the United States is largely attributable to 'deaths of despair' (deaths from suicide, drug poisonings, and alcohol-related diseases) and deaths from cardiometabolic conditions. Although despair- and cardiometabolic-related mortality are increasing concurrently, it is unclear whether they share common developmental origins. We tested adolescent psychopathology as a potential common origin of midlife diseases of despair and cardiometabolic risk.

METHODS

Participants (N = 4578) were from the National Longitudinal Study of Adolescent to Adult Health, a nationally representative cohort followed from adolescence to early midlife. Adolescent psychopathology included depression, anxiety, eating disorders, PTSD, conduct disorder, and ADHD at ages 11-18. Diseases of despair (suicidality, substance misuse, pain, and sleep problems) and cardiometabolic risk (hypertension, hyperlipidemia, high-risk waist circumference, diabetes, and cardiovascular conditions) were multi-modally measured at ages 33-43.

RESULTS

At midlife, adolescents who experienced psychopathology exhibited more indicators of despair-related diseases and cardiometabolic risk (IRRs = 1.67 [1.46-1.87] and 1.13 [1.04-1.21], respectively), even after accounting for demographics, adolescent SES, and adolescent cognitive ability. Associations were evident for internalizing and externalizing conditions, and in a dose-response fashion. In mediation analyses, low education explained little of these associations, but early-adult substance use explained 21.5% of psychopathology's association with despair-related diseases. Midlife despair-related diseases and cardiometabolic risk co-occurred within individuals (IRR = 1.12 [1.08-1.16]). Adolescent psychopathology accounted for 8.3% of this co-occurrence, and 16.7% together with adolescent SES and cognitive ability.

CONCLUSIONS

Adolescent psychopathology precedes both diseases of despair and cardiometabolic risk. Prevention and treatment of psychopathology may mitigate multiple causes of poor midlife health, reducing premature mortality.

Education and medication use later in life and the role of intelligence

We investigate the association between education and disease-specific medications in old age, prescribed by medical doctors, accounting for confounders and how this association is shaped by intelligence. We use administrative data on men including prescribed medication records. To account for endogeneity of education we estimate a structural model, consisting of (i) an ordered probit for educational attainment, (ii) a Gompertz mortality model for survival up to old age, (iii) a probit model for prescribed medications in old age, (iv) a measurement system using IQ tests to identify latent intelligence. The results suggest a strong effect of education on prescribed medications for most medications, except for prescribed medication for cardiac diseases and for depression and anxiety.

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.

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.

Mediterranean diet, physical activity, and family characteristics associated with cognitive performance in Italian primary school children: analysis of the I-MOVE project

Working memory (WM) is a multicomponent system that supports cognitive functioning. It has been linked to a wide variety of outcomes including academic success and general well-being. The present study examined the relations between adherence to the Mediterranean diet (MD) and WM among Italian children, adjusting for important parent characteristics and children's lifestyle habits. Data for this study was obtained from 106 children attending primary school in Imola (Italy) who were part of the I-MOVE study emphasizing school-based physical activity. Children's adherence to the MD was calculated using the KIDMED index (KI) based on the ZOOM-8 questionnaire. Physical activity (PA) levels were assessed using an actigraph accelerometer and WM using the backward digit span test. Univariate regression was used to select significant child-level and family measures associated with WM, which were then tested in a single multivariate regression model. Older age is positively associated with higher WM (β = 0.36; 95% CI 0.25, 0.47). Dietary adherence (KI) (β = 0.07; 95% CI 0.01, 0.14) and engagement in organized PA outside school hours (β = 0.58; 95% CI 0.09, 1.10) are positively related to WM. Among the family measures, father's education was positively associated with WM for high school education and for university vs. middle school or lower, respectively.

CONCLUSION

Adherence to the MD was associated with better WM capacity in primary school children. These findings can be used to guide policymakers in designing health promotion programs and instituting policies emphasizing healthy nutrition to improve physical health and boost cognitive functioning.

WHAT IS KNOWN

• The development of working memory involves the entire childhood with a rapid spurt between 2 and 8 years of age. • Working memory plays a critical role in children's learning and academic performance and underlies higher-order cognitive abilities.

WHAT IS NEW

• Adherence to the Mediterranean Diet was associated with higher working memory capacity in primary school children. • Health promotion interventions based on PA and sound nutrition involving children benefit not only physical and mental health, but also cognitive health.

The Associations between Results in Different Domains of Cognitive and Psychomotor Abilities Measured in Medical Students

We aimed to investigate the associations between intelligence quotient test scores obtained using the Raven's Advanced Progressive Matrices (APM) and psychomotor testing using the Complex Reactionmeter Drenovac (CRD) test battery, while taking into account previous theoretical approaches recognizing intelligent behavior as the cumulative result of a general biological speed factor reflected in the reaction time for perceptual detections and motor decisions. A total of 224 medical students at the University of Split School of Medicine were recruited. Their IQ scores were assessed using Raven's APM, while the computerized tests of CRD-series were used for testing the reaction time of perception to visual stimulus (CRD311), psychomotor limbs coordination task (CRD411), and solving simple arithmetic operations (CRD11). The total test-solving (TTST) and the minimum single-task-solving (MinT) times were analyzed. On the CRD11 test, task-solving times were shorter in students with higher APM scores (r = -0.48 for TTST and r = -0.44 for MinT; p < 0.001 for both). Negative associations between task-solving times and APM scores were reported on CRD311 (r = -0.30 for TTST and r = -0.33 for MinT, p < 0.001 for both). Negative associations between task-solving times in CRD411 and APM scores (r = -0.40 for TTST and r = -0.30 for MinT, p < 0.001 for both) were found. Faster reaction time in psychomotor limbs coordination tasks, the reaction time of perception to visual stimulus, and the reaction time of solving simple arithmetic operations were associated with a higher APM score in medical students, indicating the importance of mental speed in intelligence test performance. However, executive system functions, such as attention, planning, and goal weighting, might also impact cognitive abilities and should be considered in future research.

Social, psychological and health characteristics associated with stability and change in adult alcohol consumption

Background

Many studies analyzing health effects of alcohol consumption have operationalized alcohol intake from a single baseline measure without further follow-up. Consequently, there is a lack of knowledge about stability and change in alcohol consumption over the life course and the social, psychological, lifestyle, and health characteristics associated with different alcohol consumption trajectories.

Objectives

The aims of the study were to describe the prevalence of different adult-life alcohol consumption trajectories among Danish men and to analyze social, psychological, lifestyle and health characteristics associated with these trajectories.

Methods

For 2510 Danish men, retrospective decade-based information on alcohol consumption during life period 26–60 years was obtained in late midlife and information on individual characteristics was obtained in young adulthood, late midlife and from national hospital registries. The men were allocated to one of six a priori defined alcohol consumption trajectories.

Results

About 65% of Danish men had a stable moderate consumption, drinking 1–21 units weekly while the five other consumption trajectories were comparatively rare: 3% stable abstainers, 4.7% stable high-risk drinkers, 10.9% with increasing and 12.7% with decreasing consumption. Moderate consumption over the adult life-course was associated with the most favorable social, psychological, lifestyle and health characteristics while the other trajectories were generally associated with less favorable characteristics to varying degrees–e. g. this was the case for the stable abstaining trajectory and in particular the trajectory with decreasing consumption.

Conclusion

The findings suggest that the majority of Danish men drink moderately in the life period from young adulthood to late midlife, and deviance from this ‘normal’ moderate consumption trajectory is associated with less favorable social, psychological, lifestyle and health characteristics. Some of these characteristics may influence alcohol consumption patterns, but for some of the trajectories, alcohol consumption may influence health as well as social and psychological functioning.

The role of executive functions, social cognition and intelligence in predicting social adaptation of vulnerable populations

This study sought to evaluate the roles of and interactions between cognitive processes that have been shown to exhibit impact from socioeconomic status (SES) and living conditions in predicting social adaptation (SA) in a population of adults living in socially vulnerable conditions. Participants included 226 people between the ages of 18 and 60 who have been living in vulnerable contexts throughout life in Santiago, Chile. Data was collected through a battery of psychological assessments. A structural equation model (SEM) was implemented to examine the interrelationships among cognitive and social variables. Results indicate a significant relationship between executive function (EF) and SA through both social cognition (SC) and intelligence. Theory of Mind (ToM), a component of SC, was shown to exhibit a significant relationship with affective empathy; interestingly, this was negatively related to SA. Moreover, fluid intelligence (FI) was found to exhibit a positive, indirect relationship with SA through crystallized intelligence (CI). Evaluation of these results in the context of research on the impacts of SES and vulnerable living conditions on psychological function may allow for the development of more effective clinical, political, and social interventions to support psychosocial health among socially vulnerable populations.

Vergleich unterschiedlicher Instrumente zur Messung von Gesundheitskompetenz im Zusammenhang mit Lesekompetenz und kognitiven Fähigkeiten von Jugendlichen

Zusammenfassung. Instrumente zur Messung von Gesundheitskompetenz bei Jugendlichen basieren auf sehr heterogenen Definitionen und Konzepten. Zudem können sie grundsätzlich in subjektive (Selbsteinschätzungs–) und objektive (die Performanz messende) Verfahren unterteilt werden. In der vorliegenden Studie wurden 2 subjektive (eHEALS; Kurzform des HLS-EU-Q16) und ein objektives Messinstrument (Claim) von 471 Jugendlichen der 6. und 7. Klassenstufe (Durchschnittsalter 13.04 Jahre; 49 % Mädchen; 63 % Familiensprache Deutsch) bearbeitet und auf ihren wechselseitigen Zusammenhang, den Zusammenhang mit kognitiven und Lesefähigkeiten, sowie Unterschiede in Bezug auf Geschlecht und Familiensprache untersucht. Das objektive Verfahren korrelierte nicht mit den subjektiven Verfahren. Dies bestätigt die Annahme, dass sie aufgrund der Messperspektive unterschiedliche Indikatorenausprägungen von Gesundheitskompetenz erfassen. Korrelationen mit Lese- und kognitiven Fähigkeiten zeigten sich nur beim objektiven Instrument, wohingegen die Selbsteinschätzungsinstrumente diese Aspekte der Gesundheitskompetenz nicht abbilden. Unterschiede hinsichtlich des Geschlechts und der Familiensprache zeigten sich insbesondere beim objektiven Instrument, allerdings sind Antwortverzerrungen bei Selbsteinschätzungen möglich. Die spezifischen Vor- und Nachteile von subjektiven und objektiven Verfahren sollten bei der Instrumentenauswahl berücksichtigt werden.

Demographic factors and delay of treatment for alcohol use disorders among 6584 Danish men receiving alcohol treatment

PURPOSE

This study aimed to investigate the time lag between onset and treatment (treatment delay) for alcohol use disorders (AUD) and associations between demographic factors and treatment delay for AUD.

METHODS

The study included 6,584 men registered in the Copenhagen Alcohol Cohort, containing information on civil status, employment status, estimated age at onset of alcohol problems, and age at first outpatient AUD treatment. Data on year of birth, intelligence, and educational level were obtained from the Danish Conscription Database. Information on first hospital AUD treatment was retrieved from Danish national psychiatric registers. Associations between the demographic factors and treatment delay were analysed in separate linear regression models adjusted for year of birth and in a mutually adjusted model including all demographic factors.

RESULTS

The mean treatment delay for AUD was 6.9 years (SD = 4.1). After mutual adjustment, an SD increase in intelligence score was associated with 0.17 years increase in treatment delay. Educational level was unrelated to treatment delay. Men with estimated age at onset of alcohol problems at age 20 years or younger had a 5.30 years longer treatment delay than men who had estimated age at onset of alcohol problems at age 51 years or older. Employed men had shorter treatment delays than unemployed men, especially among the oldest birth cohorts.

CONCLUSIONS

The treatment delay of 6.9 years highlights the necessity to promote access to AUD treatment, perhaps in particular among adolescents and young individuals. Cognitive factors may affect treatment delay more than non-cognitive personal factors.

Factor structure of intelligence and divergent thinking subtests: A registered report

Psychologists have investigated creativity for 70 years, and it is now seen as being an important construct, both scientifically and because of its practical value to society. However, several fundamental unresolved problems persist, including a suitable definition of creativity and the ability of psychometric tests to measure divergent thinking—an important component of creativity—in a way that aligns with theory. It is this latter point that this registered report is designed to address. We administered two divergent thinking tests (the verbal and figural versions of the Torrance Tests of Creative Thinking; TTCT) with an intelligence test (the International Cognitive Ability Resource test; ICAR). We then subjected the subscores from these tests to confirmatory factor analysis to examine which of nine theoretically plausible models best fits the data. Results show that none of the pre-registered models fit the data well, an ambiguous result that leaves unanswered the question of whether intelligence and divergent thinking tests measure the same construct. Exploratory (i.e., not pre-registered) measurement models of each test separately shows that the TTCT-F may not measure a coherent, unitary construct—leading to model misspecification when TTCT-F subtests were included in larger models. This study was conducted in accordance with all open science practices, including pre-registration, open data and syntax, and open materials (with the exception of copyrighted and confidential test stimuli). Materials are available at https://osf.io/8rpfz/.

Limited Internal Comparability of General Intelligence Composites: Impact on External Validity, Possible Predictors, and Practical Remedies

Research on comparability of general intelligence composites (GICs) is scarce and has focused exclusively on comparing GICs from different test batteries, revealing limited individual-level comparability. We add to these findings, investigating the group- and individual-level comparability of different GICs within test batteries (i.e., internal score comparability), thereby minimizing transient error and ruling out between-battery variance completely. We (a) determined the magnitude of intraindividual IQ differences, (b) investigated their impact on external validity, (c) explored possible predictors for these differences, and (d) examined ways to deal with incomparability. Results are based on the standardization samples of three intelligence test batteries, spanning from early childhood to late adulthood. Despite high group-level comparability, individual-level comparability was often unsatisfactory, especially toward the tails of the IQ distribution. This limited comparability has consequences for external validity, as GICs were differentially related to and often less predictive for school grades for individuals with high IQ differences. Of several predictors, only IQ level and age were systematically related to comparability. Consequently, findings challenge the use of overall internal consistencies for confidence intervals and suggest using confidence intervals based on test-retest reliabilities or age- and IQ-specific internal consistencies for clinical interpretation. Implications for test construction and application are discussed.

The effect of college degree attainment on neurodegenerative symptoms in genetically at-risk women

Using longitudinal data, the present study examined the association between college degree attainment and the manifestation of neurodegenerative symptoms among women (n = 93) at elevated genetic risk. The neurodegenerative symptoms investigated in this study are due to FXTAS (Fragile X-associated Tremor/Ataxia Syndrome), a condition with onset after age 50. Those at risk for FXTAS have a mutation of a single gene found on the X chromosome. FXTAS is characterized by intention tremor, gait ataxia, executive function deficits, memory issues, and neuropathy. College degree attainment has been shown to provide neuroprotective effects in the general population, delaying the development of neurodegenerative conditions such as Alzheimer's disease. For this reason, college degree attainment is a potentially salient resource for those at risk of FXTAS. The results of the present research indicated significantly more severe FXTAS symptoms in women who did not attain a college degree as compared with those who were college graduates, although the two groups were similar in age, genetic risk, household income, health behaviors, and general health problems. Furthermore, symptoms in those who did not attain a college degree worsened over the 9-year study period at a significantly faster rate than the college graduates. The association between college degree attainment and FXTAS symptoms was significantly mediated by depression, which was lower among the graduates than those who did not attain a college degree. Thus, the present research is an example of how a sociodemographic factor can mitigate neurodegenerative conditions in genetically at-risk adults.

Characterizing and comparing adaptive and academic functioning in children with low average and below average intellectual abilities

Objective The recent American Academy of Clinical Neuropsychology (AACN) consensus statement on uniform labeling of performance test scores places children who were previously characterized as having "borderline intellectual functioning" within the low average (LA; full scale intellectual quotient (FSIQ) between 80-89) or below average (BA; FSIQ between 70-79) categories. Given limited research examining functional differences across FSIQ groups using AACN's uniform labeling, this study examined adaptive and academic functioning by FSIQ group in youth referred for (neuro)psychological evaluation. Primary comparisons of interest were between LA and BA groups. MethodParticipants were 2,516 children between 6 to 13 years with standardized measures of intellectual, adaptive, and academic functioning. Participants were included if their FSIQ ranged from average to exceptionally low. Group differences in adaptive functioning and academic achievement were examined. ResultsThe LA group did not differ from the BA group in overall adaptive functioning and several domains of adaptive functioning (i.e. social, practical), but demonstrated slightly stronger adaptive skills in the conceptual domain. While the LA group evidenced slightly better word reading and math computation scores than the BA group, these statistically significant differences were not clinically -meaningful. ConclusionsIn this clinically referred sample, children with LA and BA intellectual abilities demonstrated similar adaptive skills, but slightly different academic achievement. Both groups demonstrated lower adaptive and academic functioning than children with average range FSIQs. These results suggest that adaptive functioning should be assessed during (neuro)psychological evaluations even when children do not have extremely low FSIQs.

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.

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.

Trends in the shape of the income-mortality association in Sweden between 1995 and 2017: a repeated cross-sectional population register study

OBJECTIVE

We investigate recent trends in income inequalities in mortality and the shape of the association in Sweden. We consider all-cause, preventable and non-preventable mortality for three age groups (30-64, 65-79 and 80+ years).

DESIGN AND SETTING

Repeated cross-sectional design using Swedish total population register data.

PARTICIPANTS

All persons aged 30 years and older living in Sweden 1995-1996, 2005-2006 and 2016-2017 (n=8 084 620).

METHODS

Rate differences and rate ratios for all-cause, preventable and non-preventable mortality were calculated per income decile and age group.

RESULTS

From 1995 to 2017, relative inequalities in mortality by income increased in Sweden in the age groups 30-64 years and 65-79 years. Absolute inequalities increased in the age group 65-79 years. Among persons aged 80+ years, inequalities were small. The shape of the income-mortality association was curvilinear in the age group 30-64 years; the gradient was stronger below the fourth percentile. In the age group 65-79 years, the shape shifted from linear in 1995-1996 to a more curvilinear shape in 2016-2017. In the oldest age group (80+ years), varied shapes were observed. Inequalities were more pronounced in preventable mortality compared with non-preventable mortality. Income inequalities in preventable and non-preventable mortality increased at similar rates between 1995 and 2017.

CONCLUSIONS

The continued increase of relative (ages 30-79 years) and absolute (ages 65-79 years) mortality inequalities in Sweden should be a primary concern for public health policy. The uniform increase of inequalities in preventable and non-preventable mortality suggests that a more complex explanatory model than only social causation is responsible for increased health inequalities.

You Can Play the Game Without Knowing the Rules – But You’re Better Off Knowing Them

Abstract. Due to their high item difficulties and excellent psychometric properties, construction-based figural matrices tasks are of particular interest when it comes to high-stakes testing. An important prerequisite is that test preparation – which is likely to occur in this context – does not impair test fairness or item properties. The goal of this study was to provide initial evidence concerning the influence of test preparation. We administered test items to a sample of N = 882 participants divided into two groups, but only one group was given information about the rules employed in the test items. The probability of solving the items was significantly higher in the test preparation group than in the control group ( M = 0.61, SD = 0.19 vs. M = 0.41, SD = 0.25; t(54) = 3.42, p = .001; d = .92). Nevertheless, a multigroup confirmatory factor analysis, as well as a differential item functioning analysis, indicated no differences between the item properties in the two groups. The results suggest that construction-based figural matrices are suitable in the context of high-stakes testing when all participants are provided with test preparation material so that test fairness is ensured.

Pathfinder: a gamified measure to integrate general cognitive ability into the biological, medical, and behavioural sciences

Genome-wide association (GWA) studies have uncovered DNA variants associated with individual differences in general cognitive ability (g), but these are far from capturing heritability estimates obtained from twin studies. A major barrier to finding more of this 'missing heritability' is assessment--the use of diverse measures across GWA studies as well as time and the cost of assessment. In a series of four studies, we created a 15-min (40-item), online, gamified measure of g that is highly reliable (alpha = 0.78; two-week test-retest reliability = 0.88), psychometrically valid and scalable; we called this new measure Pathfinder. In a fifth study, we administered this measure to 4,751 young adults from the Twins Early Development Study. This novel g measure, which also yields reliable verbal and nonverbal scores, correlated substantially with standard measures of g collected at previous ages (r ranging from 0.42 at age 7 to 0.57 at age 16). Pathfinder showed substantial twin heritability (0.57, 95% CIs = 0.43, 0.68) and SNP heritability (0.37, 95% CIs = 0.04, 0.70). A polygenic score computed from GWA studies of five cognitive and educational traits accounted for 12% of the variation in g, the strongest DNA-based prediction of g to date. Widespread use of this engaging new measure will advance research not only in genomics but throughout the biological, medical, and behavioural sciences.

Information Framing Effect on Public's Intention to Receive the COVID-19 Vaccination in China

The aims of the study were (1) to explore information framing effect on the public's intention to receive the COVID-19 vaccination and (2) to understand the key factors influencing the intention of COVID-19 vaccinations in China. An online questionnaire survey was conducted to explore the influence of demographic characteristics, individual awareness, social relationship, risk disclosure, perceived vaccine efficacy, and protection duration under the assumptions of information framing. The results showed that (1) the persuasion effect under loss frame was higher than that under gain frame (B = 0.616 vs. 0.552); (2) there was no significant difference between sex, age, income, occupation, educational background and residence for the participants' intention to be vaccinated; whether family members/friends were vaccinated had a strong correlation with their vaccination intention under the gain frame; (3) the higher the understanding of COVID-19 and the compliance with government COVID-19 prevention and control measures were, the higher the vaccination intention was; (4) risk disclosure had the greatest impact on people's COVID-19 vaccination intention; (5) perceived vaccine effectiveness and duration of protection had little effect on people's intention to receive vaccination. The influence of information framing on the intention of COVID-19 vaccination is different. The publicity of relevant health information should pay attention to the influence of information framing and contents on the behavior of public vaccination, so as to enhance public health awareness and promote the vaccination of the whole population.

Age at onset and age at treatment of alcohol use disorders: Associations with educational level and intelligence

Associations of educational level and intelligence with age at onset and age at treatment of alcohol use disorders (AUD) are sparsely investigated; however, knowledge about these associations is important for an enhanced understanding of AUD. This study aimed to examine three measures of timing of AUD: estimated age at onset of alcohol problems, age at first registration in an outpatient alcohol clinic, and age at first AUD hospital diagnosis, and to estimate associations of educational level and intelligence with each measure of timing of AUD. The aims were investigated in a register-based study comprising 7,019 Danish men seeking outpatient AUD treatment. Data on educational level and intelligence were obtained from the Danish Conscription Database. Estimated age at onset of alcohol problems and age at first registration in an outpatient alcohol clinic were obtained from the Copenhagen Alcohol Cohort. Age at first AUD hospital diagnosis was retrieved from national Danish psychiatric registers. Among individuals with information on all measures of timing of AUD, 65.8% followed the developmental sequence: estimated age at onset of alcohol problems (M = 32.08 years, SD = 9.3), age at first registration in an outpatient alcohol clinic (M = 39.89 years, SD = 9.5), and age at first AUD hospital diagnosis (M = 42.27 years, SD = 12.4). Adjusted linear regression models revealed significant associations of high educational level and high intelligence with later onset and treatment of AUD, ranging from 0.61 to 0.89 years (p < 0.0001) for educational level and from 0.10 to 0.09 years (p < 0.0001) for intelligence. In conclusion, AUD develops sequentially. High educational level and intelligence were associated with later onset and treatment of AUD, but educational level explained most unique variance. This may indicate that in addition to cognitive factors reflected by both educational level and intelligence, non-cognitive factors only reflected by educational level also are important for the timing of AUD.

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.

A retrospective on fundamental cause theory: State of the literature, and goals for the future

Fundamental Cause Theory (FCT) was originally proposed to explain how socioeconomic inequalities in health emerged and persisted over time. The concept was that higher socioeconomic status helped some people to avoid risks and adopt protective strategies using flexible resources - knowledge, money, power, prestige and beneficial social connections. As a sociological theory, FCT addressed this issue by calling on social stratification, stigma, and racism as they affected medical treatments and health outcomes. The last comprehensive review was completed a decade ago. Since then, FCT has been tested, and new applications have extended central features. The current review consolidates key foci in the literature in order to guide future research in the field. Notable themes emerged around types of resources and their usage, approaches used to test the theory, and novel extensions. We conclude that after 25 years of use, there remain crucial questions to be addressed.

Circadian preference and intelligence - an updated meta-analysis

A large number of previous studies reported a link between circadian preference and psychometric intelligence with mixed results and various hypotheses about the source of this correlation. In this study, we aimed to update a previous meta-analysis about the correlation between circadian preference and intelligence. Our literature search identified a large number of new studies, resulting in an increase of over 100% in the number of studies and over 400% in the number of involved participants (total k = 30, total N = 11160) over the previous meta-analysis, sampling a much wider age range from children to adults in late middle age. Our meta-analysis revealed no significant link between morningness and intelligence (r = -0.008) when the entire sample was studied, and no evidence for publication bias. This overall effect, however, obscured the moderating effect of age. The morningness-intelligence correlation decreased with mean sample age (R² = 54%), ranging from a non-significant positive trend in children and adolescents to a significant negative correlation after young adulthood. Eveningness was positively correlated with intelligence (r = 0.056), but this finding is based on a more age-restricted sample and only reached significance with some model specifications. We hypothesize that the age-moderated correlation between circadian preference and intelligence reflects social effects, where more intelligent individuals are more able to adjust their daily schedules to their natural circadian rhythm.

Factor structure of intelligence and divergent thinking subtests: A registered report

Psychologists have investigated creativity for 70 years, and it is now seen as being an important construct, both scientifically and because of its practical value to society. However, several fundamental unresolved problems persist, including a suitable definition of creativity and the ability of psychometric tests to measure divergent thinking—an important component of creativity—in a way that aligns with theory. It is this latter point that this registered report is designed to address. We propose to administer two divergent thinking tests (the verbal and figural versions of the Torrance Tests of Creative Thinking; TTCT) with an intelligence test (the International Cognitive Ability Resource test; ICAR). We will then subject the subscores from these tests to confirmatory factor analysis to test which of nine theoretically plausible models best fits the data. When this study is completed, we hope to better understand whether the degree to which the TTCT and ICAR measure distinct constructs. This study will be conducted in accordance with all open science practices, including pre-registration, open data and syntax, and open materials (with the exception of copyrighted and confidential test stimuli).

Test Preparation in Figural Matrices Tests: Focus on the Difficult Rules

It is well documented that training the rules employed in figural matrices tests enhances test performance. Previous studies only compare experimental conditions in which all or no rules were trained and therefore ignore the particular influence of knowledge about the easy and difficult rules. With the current study, we wanted to provide some first insights into this topic. Respondents were assigned to four groups that received training for no rules, only the easy rules, only the difficult rules, or for all rules. The results show that a training only for the difficult rules was more effective than the other trainings. This applies also to performance in the easy rules that were actually not part of the training. A possible explanation for this finding is a facilitation of the solution process that is primarily driven by knowledge about the difficult rules. In conclusion, our results demonstrate that taking differences between the rules into account may provide a deeper understanding of the effects of trainings for figural matrices tests.

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.

Childhood self-control forecasts the pace of midlife aging and preparedness for old age

The ability to control one's own emotions, thoughts, and behaviors in early life predicts a range of positive outcomes in later life, including longevity. Does it also predict how well people age? We studied the association between self-control and midlife aging in a population-representative cohort of children followed from birth to age 45 y, the Dunedin Study. We measured children's self-control across their first decade of life using a multi-occasion/multi-informant strategy. We measured their pace of aging and aging preparedness in midlife using measures derived from biological and physiological assessments, structural brain-imaging scans, observer ratings, self-reports, informant reports, and administrative records. As adults, children with better self-control aged more slowly in their bodies and showed fewer signs of aging in their brains. By midlife, these children were also better equipped to manage a range of later-life health, financial, and social demands. Associations with children's self-control could be separated from their social class origins and intelligence, indicating that self-control might be an active ingredient in healthy aging. Children also shifted naturally in their level of self-control across adult life, suggesting the possibility that self-control may be a malleable target for intervention. Furthermore, individuals' self-control in adulthood was associated with their aging outcomes after accounting for their self-control in childhood, indicating that midlife might offer another window of opportunity to promote healthy aging.

What Can Experimental Studies of Bias Tell Us About Real-World Group Disparities?

This article questions the widespread use of experimental social psychology to understand real-world group disparities. Standard experimental practice is to design studies in which participants make judgments of targets who vary only on the social categories to which they belong. This is typically done under simplified decision landscapes and with untrained decision makers. For example, to understand racial disparities in police shootings, researchers show pictures of armed and unarmed Black and White men to undergraduates and have them press "shoot" and "don't shoot" buttons. Having demonstrated categorical bias under these conditions, researchers then use such findings to claim that real-world disparities are also due to decision-maker bias. I describe three flaws inherent in this approach, flaws which undermine any direct contribution of experimental studies to explaining group disparities. First, the decision landscapes used in experimental studies lack crucial components present in actual decisions (Missing Information Flaw). Second, categorical effects in experimental studies are not interpreted in light of other effects on outcomes, including behavioral differences across groups (Missing Forces Flaw). Third, there is no systematic testing of whether the contingencies required to produce experimental effects are present in real-world decisions (Missing Contingencies Flaw). I apply this analysis to three research topics to illustrate the scope of the problem. I discuss how this research tradition has skewed our understanding of the human mind within and beyond the discipline and how results from experimental studies of bias are generally misunderstood. I conclude by arguing that the current research tradition should be abandoned.

Cognitive ability × emotional stability interactions on adjustment

Cognitive ability has been shown to moderate the relations between emotional stability and self‐reports of well being. The present study examined whether this interaction effect generalizes to non‐self‐report measures of well being. Male conscripts (N = 152) completed an emotional stability scale and a cognitive ability test. Several indicators of their general adjustment and competence were derived from self‐ and superior‐ratings, a psychiatric interview and from military archives. Cognitive ability moderated the association of emotional stability with both self‐report and non‐self‐report indicators of adjustment and competence. Low emotional stability was related to adverse outcomes only among low cognitive ability individuals. The results support the idea that cognitive ability buffers the influence of emotional stability on well being. Copyright © 2009 John Wiley & Sons, Ltd.

The evolutionary genetics of personality

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

School performance and mortality: The mediating role of educational attainment and work and family trajectories across the life course

Evidence of a strong negative correlation between adolescent academic performance and mortality points to the importance of not only cognitive, but also non-cognitive, skills in predicting survival. We integrated two bodies of research to evaluate expectations regarding the role of educational attainment and trajectories of employment and marriage experience in mediating relationships between high school class rank and longevity. In particular, we used data from the Wisconsin Longitudinal Study (n = 9,232) to fit parametric mortality models from age 55 to age 77. Multiple mediator models allowed for quantification of the degree to which the association between high school class rank and mortality is mediated by life trajectories and educational attainment. Our results show that high school class rank is a statistically significant and substantively meaningful predictor of survival beyond age 55 and that this relationship is partially, but not fully, mediated by trajectories of employment and marriage experience across the life course. Higher educational attainment also mediates a substantial part of the relationship, but to varying degrees for men and women.

Communicating Intelligence Research

Despite intelligence research being among the most replicable bodies of empirical findings-a Rosetta stone across the social sciences-the communication of intelligence research with non-intelligence researchers and the public remains a challenge, especially given ongoing public controversies throughout the history of the field. Hunt argued that "we have a communication problem." This article is a call for intelligence researchers to consider communication at multiple levels-communication with other intelligence researchers, communication with non-intelligence researchers, and communication with the public, defined here as policymakers, practitioners, students, and general readers. It discusses ongoing tensions between academic freedom and social responsibility and provides suggestions for thinking about communication and effective research translation and implementation of intelligence research from the frameworks of science and policy research communication. It concludes with some recommendations for effective communication and stresses the importance of incentivizing more scholars to responsibly seek to educate and engage with multiple publics about the science of intelligence.

The intersection of individual differences, personality variation, & military service: A twin comparison design

In societies where military service is voluntary multiple factors are likely to affect the decision to enlist. Past research has produced evidence that a handful of personality and social factors seem to predict service in the military. However, recent quantitative genetic research has illustrated that enlistment in the military appears to be partially heritable and thus past research is potentially subject to genetic confounding. To assess the extent to which genetic confounding exists, the current study examined a wide range of individual-level factors using a subsample of twins (n = 1,232) from the restricted-use version of the National Longitudinal Study of Adolescent to Adult Health. The results of a series of longitudinal twin comparison models, which control for the latent sources of influence that cluster within families (i.e., shared genetic and family factors), illustrated generally null findings. However, individuals with higher scores on measures of extraversion and the general factor of personality were more likely to enlist in the military, after correction for familial confounding. Nonetheless, the overall results suggest that familial confounding should be a methodological concern in this area of research, and future work is encouraged to employ genetically informed methodologies in assessments of predictors of military enlistment.

Differential ability of network and natural language information on social media to predict interpersonal and mental health traits

Objective

Previous studies have shown that digital footprints (mainly Social Networking Services, or SNS) can predict personality traits centered on the Big Five. The present study investigates to what extent different types of SNS information predicts wider traits and attributes.

Method

We collected an intensive set of 24 (52 subscales) personality traits and attributes (N = 239) and examined whether machine learning models trained on four different types of SNS (i.e., Twitter) information (network, time, word statistics, and bag of words) predict the traits and attributes.

Results

We found that four types of SNS information can predict 23 subscales collectively. Furthermore, we validated our hypothesis that the network and word statistics information, respectively, exhibit unique strengths for the prediction of inter‐personal traits such as autism and mental health traits such as schizophrenia and anxiety. We also found that intelligence is predicted by all four types of SNS information.

Conclusions

These results reveal that the different types of SNS information can collectivity predict wider human traits and attributes than previously recognized, and also that each information type has unique predictive strengths for specific traits and attributes, suggesting that personality prediction from SNS is a powerful tool for both personality psychology and information technology.

Cognitive ability and teen smoking

We use data on 11-15-year-old boys in the West Bank to study the empirical link between cognitive ability and health behavior, specifically (teen) smoking. Adjusting for both age in months and grade level allows us to effectively shut down any simultaneous effect of maturation and schooling on cognitive ability and smoking. We find that those at the lower end of the cognitive ability distribution are more than twice as likely to smoke than those at the upper end (approximately 25 versus 10%) also after adjusting for parental background and peer composition in a generalized propensity score approach. Further, we find that the cognitive ability-smoking gradient is fairly flat at the lower end of the cognitive ability distribution and steep at the upper end.

Association of Social Mobility With the Income-Related Longevity Gap in the United States: A Cross-Sectional, County-Level Study

IMPORTANCE

Despite substantial research, the drivers of the widening gap in life expectancy between rich and poor individuals in the United States-known as the longevity gap-remain unknown. The hypothesis of this study is that social mobility may play an important role in explaining the longevity gap.

OBJECTIVE

To assess whether social mobility is associated with income-related differences in life expectancy in the United States.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional, ecological study used data from 1559 counties in the United States to assess the association of social mobility with average life expectancy at age 40 years by sex and income quartile among adult men and women over the period of January 2000 through December 2014. Bayesian generalized linear multilevel regression models were used to estimate the association, with adjustment for a range of socioeconomic, demographic, and health care system characteristics.

EXPOSURES

County-level social mobility, here operationalized as the association of the income rank of individuals born during the period of January 1980 through December 1982 (based on tax record data, averaged over the period January 2010 through December 2012) with the income ranks of their parents (averaged over the period January 1996 through December 2000) using the location where the parent first claimed the child as a dependent at age 15 years to identify counties.

MAIN OUTCOMES AND MEASURES

The main outcome was life expectancy at age 40 years by sex and income quartile.

RESULTS

The sample consisted of 1559 counties, which represented 93% of the US population in 2000. Each 1-SD increase in social mobility-equivalent to the difference between a low-mobility state, such as Alabama (ranked 49th on this measure), and a higher-mobility state, such as Massachusetts (ranked 23rd on this measure)-was associated with a 0.38-year (95% credible interval [CrI], 0.29-0.47) and a 0.29-year (95% CrI, 0.21-0.38) increase in county-level life expectancy among men and women, respectively, in the lowest income quartile. Estimates for life expectancies among county residents in the highest income quartile were smaller in magnitude and not robust to covariate adjustment (men: 0.10-year [95% CrI, -0.02 to 0.22] increase; women: 0.08-year [95% CrI, -0.05 to 0.20] increase). Increasing social mobility in all counties to the value of the highest social mobility county was associated with decreases in the life expectancy gap between the highest and lowest income quartiles by 1.4 (95% CrI, 0.7-2.1) years for men and 1.1 (95% CrI, 0.5-1.6) years for women nationally, representing a 20% decrease.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, higher county-level social mobility was associated with smaller county-level gaps in life expectancy by income. These findings motivate further investigation of causal relationships between policies that shift social mobility and health outcomes.