Only Children and Cognitive Ability in Childhood: A Cross-Cohort Analysis over 50 Years in the United Kingdom

Only children's uniqueness has intrigued researchers for decades, but many gaps in knowledge remain as to whether only children differ from children who have siblings. We use data from four British birth cohorts (born in 1946, 1958, 1970, 2000–2002) to investigate cross-cohort differences in the composition of only child families and whether the association between being an only child and cognitive ability in childhood has changed over time. Only children show similar scores to children from two child families and higher scores than children with two or more siblings across each of the cohorts analyzed. However, the results also show that—consistent with the finding that, across cohorts, the composition of the only child group has become more associated with social disadvantage—the “only child advantage” has weakened when comparing the most recent birth cohort to the older ones. Adjustment by family sociodemographic characteristics attenuates within and cross-cohort differences. Moreover, the results show that the cognitive advantages associated with being an only child vary considerably by whether the cohort member has been exposed to parental separation or is growing up in a family with lower socioeconomic status. The results highlight diversity in being an only child whose characteristics are conditional on changes throughout time and society

Weakening of the cognition and height association from 1957 to 2018: Findings from four British birth cohort studies

BACKGROUND: Taller individuals have been repeatedly found to have higher scores on cognitive assessments. Recent studies have suggested that this association can be explained by genetic factors, yet this does not preclude the influence of environmental or social factors that may change over time. We thus tested whether the association changed across time using data from four British birth cohorts (born in 1946, 1958, 1970, and 2001). METHODS: In each cohort height was measured and cognition via verbal reasoning, vocabulary/comprehension, and mathematical tests; at ages 10/11 and 14/17 years (N=41,418). We examined associations between height and cognition at each age, separately in each cohort, and for each cognitive test administered. Linear and quantile regression models were used. RESULTS: Taller participants had higher mean cognitive assessment scores in childhood and adolescence, yet the associations were weaker in later (1970 and 2001) cohorts. For example, the mean difference in height comparing the highest with lowest verbal cognition scores at 10/11 years was 0.57 SD (95% CI = 0.44-0.70) in the 1946 cohort, yet 0.30 SD (0.23-0.37) in the 2001 cohort. Expressed alternatively, there was a reduction in correlation from 0.17 (0.15-0.20) to 0.08 (0.06-0.10). This pattern of change in the association was observed across all ages and cognition measures used, was robust to adjustment for social class and parental height, and modeling of plausible missing-not-at-random scenarios. Quantile regression analyses suggested that these differences were driven by differences in the lower centiles of height, where environmental influence may be greatest. CONCLUSIONS: Associations between height and cognitive assessment scores in childhood-adolescence substantially weakened from 1957-2018. These results support the notion that environmental and social change can markedly weaken associations between cognition and other traits. FUNDING: DB is supported by the Economic and Social Research Council (grant number ES/M001660/1); DB and LW by the Medical Research Council (MR/V002147/1). The Medical Research Council (MRC) and the University of Bristol support the MRC Integrative Epidemiology Unit [MC_UU_00011/1]. NMD is supported by an Norwegian Research Council Grant number 295989. VM is supported by the CLOSER Innovation Fund WP19 which is funded by the Economic and Social Research Council (award reference: ES/K000357/1) and Economic and Social Research Council (ES/M001660/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Influence of childhood socioeconomic position and ability on mid-life cognitive function:Evidence from three British birth cohorts

Background: Childhood socioeconomic position (SEP) is robustly associated with cognitive function later in life. However, it is unclear whether this reflects a direct relationship, or an indirect association via modifiable factors such as educational attainment and occupation. We sought to clarify these associations using retrospectively harmonised data from three ongoing British birth cohorts. Methods: We analysed data from the 1946 National Survey of Health and Development (n=2283), the 1958 National Child Development Study (n=9385) and the 1970 British Cohort Study (n=7631). Retrospective harmonisation was used to derive equivalent indicators of cognition, SEP, education and occupation across the three cohorts. Structural equation modelling was used to examine the association between childhood SEP and mid-life cognitive function, via childhood cognitive ability, educational attainment and mid-life occupation. Results: Across all three cohorts, no direct pathways were observed between childhood SEP and mid-life cognitive function. Rather, this association was indirect via the three temporally ordered mediators. In addition, the direct pathway between childhood cognition and adult cognitive function was weaker in the two younger studies. Conclusions: Across three British birth cohorts, we found that the association between early life SEP and mid-life cognitive function was fully mediated by childhood cognitive ability, educational attainment and occupational status. Furthermore, the association between early cognitive ability and mid-life cognitive function has decreased in younger generations. Therefore, cognitive function in adulthood may be influenced by modifiable factors and societal change

Psychological Distress Across Adulthood: Equating Scales in Three British Birth Cohorts

Valid and reliable life-course and cross-cohort comparisons of psychological distress are limited by differences in measures used. We aimed to examine adulthood distribution of symptoms and cross-cohort trends by equating the scales of psychological-distress measures administered in the 1946, 1958, and 1970 British birth cohorts. We used data from these three birth cohorts (N = 32,242) and an independently recruited calibration sample (n = 5,800) to inform the equating of scales. We used two approaches to equating scales (equipercentile linking and multiple imputation) and two index measures (General Health Questionnaire-12 and Malaise-9) to compare means, distributions, and prevalence of distress across adulthood. Although we consistently observed an inverse U shape of distress across adulthood, we also observed measure and method differences in point estimates, particularly for cross-cohort comparisons. Sensitivity analysis suggested that multiple imputation yielded more accurate estimates than equipercentile linking. Although we observed an inverse-U-shaped trajectory of psychological distress across adulthood, differences in point estimates between measures and methods did not allow for clear conclusions regarding between-cohorts trends

Cross-Domain Symptom Development Typologies and Their Antecedents: Results From the UK Millennium Cohort Study

Objective Typologies of symptom development have been used to identify individuals with different symptom development in the externalizing and internalizing domains of child psychopathology separately despite the domains’ high comorbidity and shared common etiologic risk. This study identified typologies of development jointly across the 2 symptom domains in childhood and investigated their associated antecedents with a specific focus on the comparisons between overall severity of symptoms and symptom expression in one or the other domain. Method Latent class analysis identified groups based on emotional and behavioral symptoms assessed at 3, 5, 7, and 11 years in the UK Millennium Cohort Study (N = 15,439). Different sociodemographic, family structure and environment, birth, infancy, and early childhood antecedents were examined. Results Five groups were identified: 1. low symptoms (57%), 2. moderate behavioral (21%), 3. moderate emotional (12.5%), 4. high emotional and moderate behavioral (5.5%), and 5. high behavioral and moderate emotional (4%). Higher symptoms were predicted by larger numbers of antecedents and risk factors compared with the low symptom group and compared with moderate and high levels of symptoms in either domain (groups 5 versus 2 and 4 versus 3). Comparisons of groups with similar overall symptom levels but different dominant symptom domain (groups 2 versus 3 and 4 versus 5) indicated that apart from gender and ethnicity, there were few unique antecedents of whether children mainly internalize or externalize their symptoms. Conclusion It is possible and useful to define groupings or typologies jointly across externalizing and internalizing symptom development in childhood. Although numerous antecedents predict the experience of symptoms, there are few unique antecedents that differentiate individuals with similarly high levels of psychopathology expressed mainly as internalizing or externalizing symptoms. Identification of at-risk children and delivery of early intervention might benefit from a decreased focus on symptom domain with possible downstream effects through the life course for most common psychiatric disorders

Collection of genetic data at scale for a nationally representative population:the UK Millennium Cohort Study

A DNA bank has been created from the Millennium Cohort Study (MCS) saliva samples. A total of 23,336 samples are available, from 9,259 cohort members (4,630 males and 4,629 females), 8,898 mothers and 5,179 fathers. There are 4,533 mother, child, father ‘triads’. This paper describes the collection of the saliva samples from cohort members and their biological parents in the MCS. It analyses response rates and predictors of response, and details the DNA extraction, genotyping and imputation procedures performed on the data

Investigating change across time in prevalence or association: the challenges of cross-study comparative research and possible solutions

Cross-study research initiatives to understand change across time are an increasingly prominent component of social and health sciences, yet they present considerable practical, analytical and conceptual challenges. First, we discuss the key challenges to comparative research as a basis for detecting societal change, as well as possible solutions. We focus on studies which investigate changes across time in outcome occurrence or the magnitude and/or direction of associations. We discuss the use and importance of such research, study inclusion, sources of bias and mitigation, and interpretation. Second, we propose a structured framework (a checklist) that is intended to provide guidance for future authors and reviewers. Third, we outline a new open-access teaching resource that offers detailed instruction and reusable analytical syntax to guide newcomers on techniques for conducting comparative analysis and data visualisation (in both R and Stata formats).</p

Social health and subsequent cognitive functioning in people aged 50 years and older:examining the mediating roles of depressive symptoms and inflammatory biomarkers in two European longitudinal studies

Background: Social health markers, including marital status, contact frequency, network size, and social support, have been shown to be associated with cognition. However, the mechanisms underlying these associations remain poorly understood. We investigated whether depressive symptoms and inflammation mediated associations between social health and subsequent cognition. Methods: In the English Longitudinal Study of Ageing (ELSA), a nationally representative longitudinal study in England, UK, we sampled 7136 individuals aged 50 years or older living in private households without dementia at baseline or at the intermediate mediator assessment timepoint, who had recorded information on at least one social health marker and potential mediator. We used four-way decomposition to examine to what extent depressive symptoms, C-reactive protein, and fibrinogen mediated associations between social health and subsequent standardised cognition (verbal fluency and delayed and immediate recall), including cognitive change, with slopes derived from multilevel models (12-year slope). We examined whether findings were replicated in the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), a population-based longitudinal study in Sweden, in a sample of 2604 individuals aged 60 years or older living at home or in institutions in Kungsholmen (central Stockholm) without dementia at baseline or at the intermediate mediator assessment timepoint (6-year slope). Social health exposures were assessed at baseline, potential mediators were assessed at an intermediate timepoint (wave 2 in ELSA and 6-year follow-up in SNAC-K); cognitive outcomes were assessed at a single timepoint (wave 3 in ELSA and 12-year follow-up in SNAC-K), and cognitive change (between waves 3 and 9 in ELSA and between 6-year and 12-year follow-ups in SNAC-K). Findings: The study sample included 7136 participants from ELSA, of whom 3962 (55·5%) were women and 6934 (97·2%) were White; the mean baseline age was 63·8 years (SD 9·4). Replication analyses included 2604 participants from SNAC-K, of whom 1604 (61·6%) were women (SNAC-K did not collect ethnicity data); the mean baseline age was 72·3 years (SD 10·1). In ELSA, we found indirect effects via depressive symptoms of network size, positive support, and less negative support on subsequent verbal fluency, and of positive support on subsequent immediate recall (pure indirect effect [PIE] 0·002 [95% CI 0·001–0·003]). Depressive symptoms also partially mediated associations between less negative support and slower decline in immediate recall (PIE 0·001 [0·000–0·002]) and in delayed recall (PIE 0·001 [0·000–0·002]), and between positive support and slower decline in immediate recall (PIE 0·001 [0·000–0·001]). We did not observe mediation by inflammatory biomarkers. Findings of mediation by depressive symptoms in the association between positive support and verbal fluency and between positive support and change in immediate recall were replicated in SNAC-K. Interpretation: The findings of this study provide new insights into mechanisms linking social health with cognition, suggesting that associations between interactional aspects of social health, especially social support, and cognition are partly underpinned by depressive symptoms. Funding: EU Joint Programme—Neurodegenerative Disease Research (JPND) and Alzheimer's Society. Translation: For the Swedish translation of the abstract see Supplementary Materials section.</p

Social Class, Gender and Ethnic Differences in Subjects Taken at Age 14

In this paper we identify patterns of subject and qualification choices made at age 14. Much of the previous research on ‘subject choice’ has focussed on the later stages of educational trajectories, particularly Higher Education. However, the choices made at early branching points can limit pupils’ subsequent options, potentially contributing to educational inequalities. This paper identifies the patterns of General Certificate of Secondary Education (GCSE) subjects chosen by a cohort of young people born in 1989/1990. We make use of the Next Steps data (formerly the Longitudinal Study of Young People in England (LSYPE)) which is linked to the National Pupil Database. We develop an approach to measuring the academic selectivity of subjects and qualifications. We examine the roles of social class, parental education, income, gender and ethnicity in determining participation in these curriculum groupings. Using measures of prior attainment from age thirteen, we address the question of whether curriculum differentials simply reflect differences in prior attainment or whether they actually operate above and beyond existing inequalities. We find clear socio-economic, gender, ethnic and school-level differences in subjects studied which cannot be accounted for by prior attainment

Building a transdisciplinary expert consensus on the cognitive drivers of performance under pressure: An international multi-panel Delphi study

IntroductionThe ability to perform optimally under pressure is critical across many occupations, including the military, first responders, and competitive sport. Despite recognition that such performance depends on a range of cognitive factors, how common these factors are across performance domains remains unclear. The current study sought to integrate existing knowledge in the performance field in the form of a transdisciplinary expert consensus on the cognitive mechanisms that underlie performance under pressure.MethodsInternational experts were recruited from four performance domains [(i) Defense; (ii) Competitive Sport; (iii) Civilian High-stakes; and (iv) Performance Neuroscience]. Experts rated constructs from the Research Domain Criteria (RDoC) framework (and several expert-suggested constructs) across successive rounds, until all constructs reached consensus for inclusion or were eliminated. Finally, included constructs were ranked for their relative importance.ResultsSixty-eight experts completed the first Delphi round, with 94% of experts retained by the end of the Delphi process. The following 10 constructs reached consensus across all four panels (in order of overall ranking): (1) Attention; (2) Cognitive Control—Performance Monitoring; (3) Arousal and Regulatory Systems—Arousal; (4) Cognitive Control—Goal Selection, Updating, Representation, and Maintenance; (5) Cognitive Control—Response Selection and Inhibition/Suppression; (6) Working memory—Flexible Updating; (7) Working memory—Active Maintenance; (8) Perception and Understanding of Self—Self-knowledge; (9) Working memory—Interference Control, and (10) Expert-suggested—Shifting.DiscussionOur results identify a set of transdisciplinary neuroscience-informed constructs, validated through expert consensus. This expert consensus is critical to standardizing cognitive assessment and informing mechanism-targeted interventions in the broader field of human performance optimization