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Dong L, Giangrande EJ, Womack SR, Yoo K, Beam CR, Jacobson KC, Turkheimer E. A Longitudinal Analysis of Gene x Environment Interaction on Verbal Intelligence Across Adolescence and Early Adulthood. Behav Genet 2023; 53:311-330. [PMID: 37171531 DOI: 10.1007/s10519-023-10145-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 04/21/2023] [Indexed: 05/13/2023]
Abstract
The Scarr-Rowe hypothesis proposes that the heritability of intelligence is higher in more advantaged socioeconomic contexts. An early demonstration of this hypothesis was Rowe and colleagues (Rowe et al., Child Dev 70:1151-1162, 1999), where an interaction between the heritability of verbal intelligence and parental education was identified in adolescent siblings in Wave I of the National Longitudinal Study of Adolescent to Adult Health. The present study repeated their original analysis at Wave I using contemporary methods, replicated the finding during young adulthood at Wave III, and analyzed the interaction longitudinally utilizing multiple measurements. We examined parental education, family income, and peer academic environment as potential moderators. Results indicated increased heritability and decreased shared environmental variance of verbal intelligence at higher levels of parental education and peer academic environment in adolescence. Moreover, moderation by peer academic environment persisted into adulthood with its effect partially attributable to novel gene-environment interactions that arose in the process of cognitive development.
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Affiliation(s)
- LiChen Dong
- Department of Psychology, University of Wisconsin - Madison, Madison, WI, USA.
| | - Evan J Giangrande
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
| | - Sean R Womack
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
| | - Kristy Yoo
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Christopher R Beam
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Kristen C Jacobson
- Department of Psychiatry & Behavioral Neuroscience, University of Chicago, Chicago, IL, USA
| | - Eric Turkheimer
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
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2
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Masini A, Sanmarchi F, Kawalec A, Esposito F, Scrimaglia S, Tessari A, Scheier LM, Sacchetti R, Dallolio L. Mediterranean diet, physical activity, and family characteristics associated with cognitive performance in Italian primary school children: analysis of the I-MOVE project. Eur J Pediatr 2023; 182:917-927. [PMID: 36525096 DOI: 10.1007/s00431-022-04756-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 11/29/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022]
Abstract
UNLABELLED 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.
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Affiliation(s)
- Alice Masini
- Department of Biomedical and Neuromotor Science Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Francesco Sanmarchi
- Department of Biomedical and Neuromotor Science Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Anna Kawalec
- Department and Clinic of Paediatric Nephrology, Wroclaw Medical University, Wroclaw, Poland
| | - Francesco Esposito
- Department of Biomedical and Neuromotor Science Alma Mater Studiorum, University of Bologna, Bologna, Italy.
| | - Susan Scrimaglia
- Department of Biomedical and Neuromotor Science Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Alessia Tessari
- Department of Psychology "Renzo Canestrari", Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Lawrence M Scheier
- LARS Research Institute, Inc., Sun City, AZ, USA
- Prevention Strategies, Greensboro, NC, USA
| | - Rossella Sacchetti
- Department of Education Studies "Giovanni Maria Bertin", Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Laura Dallolio
- Department of Biomedical and Neuromotor Science Alma Mater Studiorum, University of Bologna, Bologna, Italy
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Loehlin JC, Corley RP, Reynolds CA, Wadsworth SJ. Heritability × SES Interaction for IQ: Is it Present in US Adoption Studies? Behav Genet 2022; 52:48-55. [PMID: 34436691 PMCID: PMC9255665 DOI: 10.1007/s10519-021-10080-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 08/13/2021] [Indexed: 01/03/2023]
Abstract
An interaction between socioeconomic status (SES) and the heritability of IQ, such that the heritability of IQ increases with higher SES, has been reported in some US twin studies, although not in others, and has generally been absent in studies outside the US (England, Europe, Australia). Is such an interaction present in US adoption studies? Data from two such studies, the Texas and the Colorado Adoption Projects, were examined, involving 238-469 adopted children given IQ tests at various ages. A mini multi-level analysis was made of the prediction of the IQs by the SES of the rearing home (a composite of parental education and occupation), by the birth mother's intelligence, and by the interaction of the two. Neither study showed any substantial heritability × SES interaction: the effect size estimates in units comparable to twin moderation models were negative (- 0.042 and - 0.004), and the meta-analytic estimate for the combined analysis was - 0.27 (SE = 0.042) with a 95% confidence interval of - 0.109 to 0.054. Thus, while we cannot rule out positive moderation based on our two studies, the joint agreement across these studies, and with the non-US twin studies, warrants attention in further research. SES may not fully capture proximal familial-environmental aspects that moderate child IQ.
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Affiliation(s)
- John C. Loehlin
- Department of Psychology, University of Texas,Dr. Loehlin died between the original submission of this paper and this revision
| | - Robin P. Corley
- Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, CO 80309,To whom correspondence should be addressed
| | - Chandra A. Reynolds
- Department of Psychology, University of California at Riverside, Riverside, CA 92521
| | - Sally J. Wadsworth
- Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, CO 80309
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Rask-Andersen M, Karlsson T, Ek WE, Johansson Å. Modification of Heritability for Educational Attainment and Fluid Intelligence by Socioeconomic Deprivation in the UK Biobank. Am J Psychiatry 2021; 178:625-634. [PMID: 33900812 DOI: 10.1176/appi.ajp.2020.20040462] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Socioeconomic factors have been suggested to influence the effect of education- and intelligence-associated genetic variants. However, results from previous studies on the interaction between socioeconomic status and education or intelligence have been inconsistent. The authors sought to assess these interactions in the UK Biobank cohort of 500,000 participants. METHODS The authors assessed the effect of socioeconomic deprivation on education- and intelligence-associated genetic variants by estimating the single-nucleotide polymorphism (SNP) heritability for fluid intelligence, educational attainment, and years of education in subsets of UK Biobank participants with different degrees of social deprivation, using linkage disequilibrium score regression. They also generated polygenic scores with LDpred and tested for interactions with social deprivation. RESULTS SNP heritability increased with socioeconomic deprivation for fluid intelligence, educational attainment, and years of education. Polygenic scores were also found to interact with socioeconomic deprivation, where the effects of the scores increased with increasing deprivation for all traits. CONCLUSIONS These results indicate that genetics have a larger influence on educational and cognitive outcomes in more socioeconomically deprived U.K. citizens, which has serious implications for equality of opportunity.
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Affiliation(s)
- Mathias Rask-Andersen
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Torgny Karlsson
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Weronica E Ek
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Åsa Johansson
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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Parental Education, Household Income, Race, and Children's Working Memory: Complexity of the Effects. Brain Sci 2020; 10:brainsci10120950. [PMID: 33297546 PMCID: PMC7762416 DOI: 10.3390/brainsci10120950] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/01/2020] [Accepted: 12/04/2020] [Indexed: 12/20/2022] Open
Abstract
Background. Considerable research has linked social determinants of health (SDoHs) such as race, parental education, and household income to school performance, and these effects may be in part due to working memory. However, a growing literature shows that these effects may be complex: while the effects of parental education may be diminished for Blacks than Whites, household income may explain such effects. Purpose. Considering race as sociological rather than a biological construct (race as a proxy of racism) and built on Minorities' Diminished Returns (MDRs), this study explored complexities of the effects of SDoHs on children's working memory. Methods. We borrowed data from the Adolescent Brain Cognitive Development (ABCD) study. The total sample was 10,418, 9- and 10-year-old children. The independent variables were race, parental education, and household income. The primary outcome was working memory measured by the NIH Toolbox Card Sorting Test. Age, sex, ethnicity, and parental marital status were the covariates. To analyze the data, we used mixed-effect regression models. Results. High parental education and household income were associated with higher and Black race was associated with lower working memory. The association between high parental education but not household income was less pronounced for Black than White children. This differential effect of parental education on working memory was explained by household income. Conclusions. For American children, parental education generates unequal working memory, depending on race. This means parental education loses some of its expected effects for Black families. It also suggests that while White children with highly educated parents have the highest working memory, Black children report lower working memory, regardless of their parental education. This inequality is mainly because of differential income in highly educated White and Black families. This finding has significant public policy and economic implications and suggests we need to do far more than equalizing education to eliminate racial inequalities in children's cognitive outcomes. While there is a need for multilevel policies that reduce the effect of racism and social stratification for middle-class Black families, equalizing income may have more returns than equalizing education.
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Halpern-Manners A, Marahrens H, Neiderhiser JM, Natsuaki MN, Shaw DS, Reiss D, Leve LD. The Intergenerational Transmission of Early Educational Advantages: New Results Based on an Adoption Design. RESEARCH IN SOCIAL STRATIFICATION AND MOBILITY 2020; 67:100486. [PMID: 32724268 PMCID: PMC7386403 DOI: 10.1016/j.rssm.2020.100486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sociological research has traditionally emphasized the importance of post-birth factors (i.e., social, economic, and cultural capital) in the intergenerational transmission of educational advantages, to the neglect of potentially consequential pre-birth endowments (e.g., heritable traits) that are passed from parent to child. In this study, we leverage an experiment of nurture-children who were adopted at birth into nonrelative families-in an effort to simultaneously model the effects associated with both pathways. To do so, we fit a series of simple linear regression models that relate the academic achievement of adopted children to the educational attainments of their adoptive and biological parents, using U.S. data from a recent nationwide sample of birth and adoptive families (the Early Growth and Development Study). Because our dataset includes both "genetic" and "environmental" relatives, but not "genetic-and-environmental" relatives, the separate contributions of each pathway can be identified, as well as possible interactions between the two. Our results show that children's early achievements are influenced not only by the attainments of their adoptive parents, but also the attainments of their birth parents-suggesting the presence of environmental and genetically mediated effects. Supplementary analyses provide little evidence of effect moderation, using both distal and proximate measures of the childhood environment to model gene-by-environment interactions. These findings are robust to a variety of parameterizations, withstand a series of auxiliary checks, and remain intact even after controlling for intrauterine exposures and other measurable variables that could compromise our design. The implications of our results for theory and research in the stratification literature, and for those interested in educational mobility, are discussed.
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Affiliation(s)
| | | | | | | | | | - David Reiss
- Child Study Center, Yale School of Medicine, Yale University
| | - Leslie D. Leve
- Department of Counseling Psychology and Human Services, University of Oregon
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Rabinowitz JA, Kuo SIC, Domingue B, Smart M, Felder W, Benke K, Maher BS, Ialongo NS, Uhl G. Pathways Between a Polygenic Score for Educational Attainment and Higher Educational Attainment in an African American Sample. Behav Genet 2019; 50:14-25. [PMID: 31760550 DOI: 10.1007/s10519-019-09982-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/15/2019] [Indexed: 01/22/2023]
Abstract
We investigated the extent to which performance on standardized achievement tests, executive function (EF), and aggression in childhood and adolescence accounted for the relationship between a polygenic score for educational attainment (EA PGS) and years of education in a community sample of African Americans. Participants (N = 402; 49.9% female) were initially recruited for an elementary school-based prevention trial in a Mid-Atlantic city and followed into adulthood. In first and twelfth grade, participants completed math and reading standardized tests and teachers reported on participants' aggression and EF, specifically impulsivity and concentration problems. At age 20, participants reported on their years of education and post-secondary degrees attained and their genotype was assayed from blood or buccal swabs. An EA PGS was created using results from a large-scale GWAS on EA. A higher EA PGS was associated with higher education indirectly via adolescent achievement. No other mediating mechanisms were significant. Adolescent academic achievement is thus one mechanism through which polygenic propensity for EA influences post-secondary education among urban, African American youth.
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Affiliation(s)
- Jill A Rabinowitz
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Heath, Baltimore, USA.
| | - Sally I-Chun Kuo
- Department of Psychology, Virginia Commonwealth University, Richmond, USA
| | | | - Mieka Smart
- College of Human Medicine, Michigan State University, East Lansing, USA
| | - William Felder
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Heath, Baltimore, USA
| | - Kelly Benke
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Heath, Baltimore, USA
| | - Brion S Maher
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Heath, Baltimore, USA
| | - Nicholas S Ialongo
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Heath, Baltimore, USA
| | - George Uhl
- New Mexico VA Health Care System, Las Vegas, USA
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Giangrande EJ, Beam CR, Carroll S, Matthews LJ, Davis DW, Finkel D, Turkheimer E. Multivariate analysis of the Scarr-Rowe interaction across middle childhood and early adolescence. INTELLIGENCE 2019. [DOI: 10.1016/j.intell.2019.101400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gottschling J, Hahn E, Beam CR, Spinath FM, Carroll S, Turkheimer E. Socioeconomic status amplifies genetic effects in middle childhood in a large German twin sample. INTELLIGENCE 2019; 72:20-27. [PMID: 31435119 PMCID: PMC6703848 DOI: 10.1016/j.intell.2018.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The Scarr-Rowe hypothesis predicts that the heritability of cognitive abilities is higher in more privileged socioeconomic conditions, meaning that genetic potential can be more fully expressed in environments characterized by high socioeconomic status (SES) compared to low SES. This gene × SES interaction, however, has been replicated mostly in the United States, but not in other Western nations like the United Kingdom. In the current study, we tested the interaction between childhood SES and the heritability of cognitive ability in 3,074 German twin pairs comprising three age cohorts at different developmental stages (mean ages of 11, 17, and 23 years). Higher SES was associated with significantly higher mean cognitive ability scores in the two younger cohorts, with reduced variances at higher SES levels. Results further support the Scarr-Rowe hypothesis in middle childhood, and to some degree in adolescence, but not in adulthood. This indicates that the role of family SES as a moderator of the heritability of cognitive ability changes as children grow older. Moreover, children's shared experiences appear to be explain more variance in cognitive ability at the lower end of the SES distribution in middle childhood and adolescence.
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Affiliation(s)
- J Gottschling
- Department of Psychology, Saarland University, Saarbruecken, Germany
- Cognitive Science & Assessment, University of Luxembourg, Luxembourg
| | - E Hahn
- Department of Psychology, Saarland University, Saarbruecken, Germany
| | - C. R Beam
- Department of Psychology, University of Southern California, California, USA
| | - F. M Spinath
- Department of Psychology, Saarland University, Saarbruecken, Germany
| | - S Carroll
- Department of Psychology, University of Virginia, Virginia, USA
- Department of Psychology, Michigan State University, Michigan, USA
| | - E Turkheimer
- Department of Psychology, University of Virginia, Virginia, USA
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10
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Zavala C, Beam CR, Finch BK, Gatz M, Johnson W, Kremen WS, Neiderhiser JM, Pedersen NL, Reynolds CA. Attained SES as a moderator of adult cognitive performance: Testing gene-environment interaction in various cognitive domains. Dev Psychol 2018; 54:2356-2370. [PMID: 30335430 PMCID: PMC6263814 DOI: 10.1037/dev0000576] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We examined whether attained socioeconomic status (SES) moderated genetic and environmental sources of individual differences in cognitive performance using pooled data from 9 adult twin studies. Prior work concerning SES moderation of cognitive performance has focused on rearing SES. The current adult sample of 12,196 individuals (aged 27-98 years) allowed for the examination of common sources of individual differences between attained SES and cognitive performance (signaling potential gene-environment correlation mechanisms, rGE), as well as sources of individual differences unique to cognitive performance (signaling potential gene-environment interaction mechanisms, G × E). Attained SES moderated sources of individual differences in 4 cognitive domains, assessed via performance on 5 cognitive tests ranging 2,149 to 8,722 participants. Attained SES moderated common sources of influences for 3 domains and influences unique to cognition in all 4 domains. The net effect was that genetic influences on the common pathway tended to be relatively more important at the upper end of attained SES indicating possible active rGE, whereas, genetic influences for the unique pathway were proportionally stable or less important at the upper end of attained SES. As a noted exception, at the upper end of attained SES, genetic influences unique to perceptual speed were amplified and genetic influences on the common pathway were dampened. Accounting for rearing SES did not alter attained SES moderation effects on cognitive performance, suggesting mechanisms germane to adulthood. Our findings suggest the importance of gene-environment mechanisms through which attained SES moderates sources of individual differences in cognitive performance. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
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Affiliation(s)
| | | | | | | | - Wendy Johnson
- Centre for Cognitive Ageing & Cognitive Epidemiology and Department of Psychology, University of Edinburgh
| | - William S Kremen
- Department of Psychiatry and Center for Behavior Genetics of Aging, University of California
| | | | - Nancy L Pedersen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, University of Southern California
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11
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Socioeconomic status and genetic influences on cognitive development. Proc Natl Acad Sci U S A 2017; 114:13441-13446. [PMID: 29133413 DOI: 10.1073/pnas.1708491114] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status (SES) families, including recent proposals that the pattern is a particularly US phenomenon. We used matched birth and school records from Florida siblings and twins born in 1994-2002 to provide the largest, most population-diverse consideration of this hypothesis to date. We found no evidence of SES moderation of genetic influence on test scores, suggesting that articulating gene-environment interactions for cognition is more complex and elusive than previously supposed.
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Barreto FB, Sánchez de Miguel M, Ibarluzea J, Andiarena A, Arranz E. Family context and cognitive development in early childhood: A longitudinal study. INTELLIGENCE 2017. [DOI: 10.1016/j.intell.2017.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Grasby KL, Coventry WL, Byrne B, Olson RK. Little Evidence That Socioeconomic Status Modifies Heritability of Literacy and Numeracy in Australia. Child Dev 2017; 90:623-637. [PMID: 28832969 DOI: 10.1111/cdev.12920] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Socioeconomic status (SES) has been found to moderate the influence of genes and the environment on cognitive ability, such that genetic influence is greater when SES is higher, and the shared environment is greater when SES is lower, but not in all Western countries. The effects of both family and school SES on the heritability of literacy and numeracy in Australian twins aged 8, 10, 12, and 14 years with 1,307, 1,235, 1,076, and 930 pairs at each age, respectively, were tested. Shared environmental influences on Grade 3 literacy were greater with low family SES, and no other moderating effects of SES were significant. These findings are contrasted with results from the United States and the United Kingdom.
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Affiliation(s)
- Katrina L Grasby
- Queensland Institute of Medical Research.,University of New England
| | | | - Brian Byrne
- University of New England.,Australian Research Council Centre of Excellence for Cognition and its Disorders.,National Health and Medical Research Council Centre of Excellence in Twin Research
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14
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Bates TC, Hansell NK, Martin NG, Wright MJ. When does socioeconomic status (SES) moderate the heritability of IQ? No evidence for g × SES interaction for IQ in a representative sample of 1176 Australian adolescent twin pairs. INTELLIGENCE 2016. [DOI: 10.1016/j.intell.2016.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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Reynolds CA, Gatz M, Christensen K, Christiansen L, Dahl Aslan AK, Kaprio J, Korhonen T, Kremen WS, Krueger R, McGue M, Neiderhiser JM, Pedersen NL. Gene-Environment Interplay in Physical, Psychological, and Cognitive Domains in Mid to Late Adulthood: Is APOE a Variability Gene? Behav Genet 2016; 46:4-19. [PMID: 26538244 PMCID: PMC4858319 DOI: 10.1007/s10519-015-9761-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
Abstract
Despite emerging interest in gene-environment interaction (GxE) effects, there is a dearth of studies evaluating its potential relevance apart from specific hypothesized environments and biometrical variance trends. Using a monozygotic within-pair approach, we evaluated evidence of G×E for body mass index (BMI), depressive symptoms, and cognition (verbal, spatial, attention, working memory, perceptual speed) in twin studies from four countries. We also evaluated whether APOE is a 'variability gene' across these measures and whether it partly represents the 'G' in G×E effects. In all three domains, G×E effects were pervasive across country and gender, with small-to-moderate effects. Age-cohort trends were generally stable for BMI and depressive symptoms; however, they were variable-with both increasing and decreasing age-cohort trends-for different cognitive measures. Results also suggested that APOE may represent a 'variability gene' for depressive symptoms and spatial reasoning, but not for BMI or other cognitive measures. Hence, additional genes are salient beyond APOE.
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Affiliation(s)
- Chandra A Reynolds
- Department of Psychology, University of California Riverside, 900 University Ave., Riverside, CA, 92521, USA.
| | - Margaret Gatz
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 17177, Stockholm, Sweden
| | - Kaare Christensen
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, 5000, Odense C, Denmark
- Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
| | - Lene Christiansen
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, 5000, Odense C, Denmark
| | - Anna K Dahl Aslan
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 17177, Stockholm, Sweden
- Institute of Gerontology, School of Health and Welfare, Jönköping University, Jönköping, Sweden
| | - Jaakko Kaprio
- Department of Public Health & Institute for Molecular Medicine FIMM, University of Helsinki, 00014, Helsinki, Finland
| | - Tellervo Korhonen
- Department of Public Health, University of Helsinki, 00014, Helsinki, Finland
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70211, Kuopio, Finland
| | - William S Kremen
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093, USA
| | - Robert Krueger
- Department of Psychology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Matt McGue
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, 5000, Odense C, Denmark
- Department of Psychology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jenae M Neiderhiser
- Department of Psychology, The Pennsylvania State University, University Park, PA, USA
| | - Nancy L Pedersen
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 17177, Stockholm, Sweden
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Tucker-Drob EM, Bates TC. Large Cross-National Differences in Gene × Socioeconomic Status Interaction on Intelligence. Psychol Sci 2015; 27:138-149. [PMID: 26671911 DOI: 10.1177/0956797615612727] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 09/29/2015] [Indexed: 11/17/2022] Open
Abstract
A core hypothesis in developmental theory predicts that genetic influences on intelligence and academic achievement are suppressed under conditions of socioeconomic privation and more fully realized under conditions of socioeconomic advantage: a Gene × Childhood Socioeconomic Status (SES) interaction. Tests of this hypothesis have produced apparently inconsistent results. We performed a meta-analysis of tests of Gene × SES interaction on intelligence and academic-achievement test scores, allowing for stratification by nation (United States vs. non-United States), and we conducted rigorous tests for publication bias and between-studies heterogeneity. In U.S. studies, we found clear support for moderately sized Gene × SES effects. In studies from Western Europe and Australia, where social policies ensure more uniform access to high-quality education and health care, Gene × SES effects were zero or reversed.
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South SC, Hamdi NR, Krueger RF. Biometric Modeling of Gene-Environment Interplay: The Intersection of Theory and Method and Applications for Social Inequality. J Pers 2015; 85:22-37. [PMID: 26426103 DOI: 10.1111/jopy.12231] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
For more than a decade, biometric moderation models have been used to examine whether genetic and environmental influences on individual differences might vary within the population. These quantitative Gene × Environment interaction models have the potential to elucidate not only when genetic and environmental influences on a phenotype might differ, but also why, as they provide an empirical test of several theoretical paradigms that serve as useful heuristics to explain etiology-diathesis-stress, bioecological, differential susceptibility, and social control. In the current article, we review how these developmental theories align with different patterns of findings from statistical models of gene-environment interplay. We then describe the extant empirical evidence, using work by our own research group and others, to lay out genetically informative plausible accounts of how phenotypes related to social inequality-physical health and cognition-might relate to these theoretical models.
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The Scarr-Rowe Interaction in Complete Seven-Year WISC Data from the Louisville Twin Study: Preliminary Report. Behav Genet 2015; 45:635-9. [PMID: 26497158 DOI: 10.1007/s10519-015-9760-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/07/2015] [Indexed: 10/22/2022]
Abstract
We examine updated Wechsler IQ data in 7-year old twins from the Louisville Twin Study for evidence of an interaction between the heritability of IQ and socioeconomic status. Data records that had never been entered were recovered, allowing us to increase previously reported sample sizes by more than 20%. Twin families were assigned socioeconomic status scores using a Hollingshead index based on parental education and occupation. A structural equation model in which genetic and environmental variances were modeled as squared linear functions of SES provided ambiguous replication of earlier findings from the National Collaborative Perinatal Project: relations between SES and heritability for performance and full scale IQ were in the same direction as the previous report, but at p < 0.07. As was the case in Turkheimer et al. (Psychol Sci 14(6):623-628, 2003), no interaction was found for VIQ. These results cannot yet be taken as a definitive replication of Turkheimer et al. (Psychol Sci 14(6):623-628, 2003). Many more measurement occasions, subtests and environmental moderators remain to be analyzed.
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Schwartz JA. Socioeconomic status as a moderator of the genetic and shared environmental influence on verbal IQ: A multilevel behavioral genetic approach. INTELLIGENCE 2015. [DOI: 10.1016/j.intell.2015.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Relation of intelligence quotient and body mass index in preschool children: a community-based cross-sectional study. Nutr Diabetes 2015; 5:e176. [PMID: 26258767 PMCID: PMC4558558 DOI: 10.1038/nutd.2015.27] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 06/18/2015] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE Overweight and obesity in children is a global problem. Besides physical effects, obesity has harmful psychological effects on children. METHODS We carried out cross-sectional community-based study to investigate the relation between body mass index (BMI) and cognitive functioning in preschool children. Thirteen socioeconomical elements of 1151 children were measured and analyzed based on their intelligence quotient (IQ) test results. Thirteen out of 33 provinces were selected randomly, and schools were selected as clusters in rural and urban areas. Descriptive statistics, t-test, analysis of variance and regression were used when appropriate. RESULTS Our analysis showed that IQ was associated with household income, place of residence, delivery type, type of infant feeding and father's and mother's education level (P<0.001 for all). Using penalized linear regression for eliminating the impact of confounding factor, our study shows that, living in metropolitan (β=2.411) and urban areas (β=2.761), the level of participants' father's education (β=5.251) was positively and BMI (β=-0.594) was negatively related with IQ test results.ConclusionsThe findings of the present study showed that a lower IQ score is associated with higher BMI. However, this relation appears to be largely mediated when the socioeconomic status was considered.
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Hanges PJ, Aiken JR, Salmon ED. The Devil Is in the Details (and the Context): A Call for Care in Discussing the Uniform Guidelines. INDUSTRIAL AND ORGANIZATIONAL PSYCHOLOGY-PERSPECTIVES ON SCIENCE AND PRACTICE 2015. [DOI: 10.1111/j.1754-9434.2011.01393.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kirkpatrick RM, McGue M, Iacono WG. Replication of a gene-environment interaction Via Multimodel inference: additive-genetic variance in adolescents' general cognitive ability increases with family-of-origin socioeconomic status. Behav Genet 2014; 45:200-14. [PMID: 25539975 DOI: 10.1007/s10519-014-9698-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 12/07/2014] [Indexed: 10/24/2022]
Abstract
The present study of general cognitive ability attempts to replicate and extend previous investigations of a biometric moderator, family-of-origin socioeconomic status (SES), in a sample of 2,494 pairs of adolescent twins, non-twin biological siblings, and adoptive siblings assessed with individually administered IQ tests. We hypothesized that SES would covary positively with additive-genetic variance and negatively with shared-environmental variance. Important potential confounds unaddressed in some past studies, such as twin-specific effects, assortative mating, and differential heritability by trait level, were found to be negligible. In our main analysis, we compared models by their sample-size corrected AIC, and base our statistical inference on model-averaged point estimates and standard errors. Additive-genetic variance increased with SES-an effect that was statistically significant and robust to model specification. We found no evidence that SES moderated shared-environmental influence. We attempt to explain the inconsistent replication record of these effects, and provide suggestions for future research.
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Affiliation(s)
- Robert M Kirkpatrick
- Department of Psychology, University of Minnesota, 75 E. River Rd, Minneapolis, MN, 55455, USA,
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23
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Vuoksimaa E, Panizzon MS, Chen CH, Fiecas M, Eyler LT, Fennema-Notestine C, Hagler DJ, Fischl B, Franz CE, Jak A, Lyons MJ, Neale MC, Rinker DA, Thompson WK, Tsuang MT, Dale AM, Kremen WS. The Genetic Association Between Neocortical Volume and General Cognitive Ability Is Driven by Global Surface Area Rather Than Thickness. Cereb Cortex 2014; 25:2127-37. [PMID: 24554725 DOI: 10.1093/cercor/bhu018] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Total gray matter volume is associated with general cognitive ability (GCA), an association mediated by genetic factors. It is expectable that total neocortical volume should be similarly associated with GCA. Neocortical volume is the product of thickness and surface area, but global thickness and surface area are unrelated phenotypically and genetically in humans. The nature of the genetic association between GCA and either of these 2 cortical dimensions has not been examined. Humans possess greater cognitive capacity than other species, and surface area increases appear to be the primary driver of the increased size of the human cortex. Thus, we expected neocortical surface area to be more strongly associated with cognition than thickness. Using multivariate genetic analysis in 515 middle-aged twins, we demonstrated that both the phenotypic and genetic associations between neocortical volume and GCA are driven primarily by surface area rather than thickness. Results were generally similar for each of 4 specific cognitive abilities that comprised the GCA measure. Our results suggest that emphasis on neocortical surface area, rather than thickness, could be more fruitful for elucidating neocortical-GCA associations and identifying specific genes underlying those associations.
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Affiliation(s)
- Eero Vuoksimaa
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory Department of Public Health, University of Helsinki, Helsinki, Finland
| | - Matthew S Panizzon
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory
| | - Chi-Hua Chen
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory
| | - Mark Fiecas
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory
| | - Lisa T Eyler
- Department of Psychiatry Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System, San Diego, CA, USA
| | | | | | - Bruce Fischl
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA Computer Science and AI Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Carol E Franz
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory
| | - Amy Jak
- Department of Psychiatry Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA, USA
| | - Michael J Lyons
- Department of Psychology, Boston University, Boston, MA, USA
| | - Michael C Neale
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | | | | | - Ming T Tsuang
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory
| | - Anders M Dale
- Department of Radiology and Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - William S Kremen
- Department of Psychiatry Center for Behavioral Genomics Twin Research Laboratory Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA, USA
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Hart SA, Soden B, Johnson W, Schatschneider C, Taylor J. Expanding the environment: gene × school-level SES interaction on reading comprehension. J Child Psychol Psychiatry 2013; 54:1047-55. [PMID: 23725549 PMCID: PMC3766464 DOI: 10.1111/jcpp.12083] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/26/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND Influential work has explored the role of family socioeconomic status (SES) as an environmental moderator of genetic and environmental influences on cognitive outcomes. This work has provided evidence that socioeconomic circumstances differentially impact the heritability of cognitive abilities, generally supporting the bioecological model in that genetic influences are greater at higher levels of family SES. The present work expanded consideration of the environment, using school-level SES as a moderator of reading comprehension. METHODS The sample included 577 pairs of twins from the Florida Twin Project on Reading, Behavior and Environment. Reading comprehension was measured by the Florida Comprehensive Achievement Test (FCAT) Reading in third or fourth grade. School-level SES was measured by the mean Free and Reduced Lunch Status (FRLS) of the schoolmates of the twins. RESULTS The best-fitting univariate G × E moderation model indicated greater genetic influences on reading comprehension when fewer schoolmates qualified for FRLS (i.e., 'higher' school-level SES). There was also an indication of moderation of the shared environment; there were greater shared environmental influences on reading comprehension at higher school-level SES. CONCLUSIONS The results supported the bioecological model; greater genetic variance was found in school environments in which student populations experienced less poverty. In general, 'higher' school-level SES allowed genetic and probably shared environmental variance to contribute as sources of individual differences in reading comprehension outcomes. Poverty suppresses these influences.
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Affiliation(s)
- Sara A. Hart
- Department of Psychology, Florida State University, United States
,Florida Center for Reading Research, Florida State University, United States
| | - Brooke Soden
- Department of Psychology, The Ohio State University, United States
| | - Wendy Johnson
- Department of Psychology, University of Edinburgh, United Kingdom
| | - Christopher Schatschneider
- Department of Psychology, Florida State University, United States
,Florida Center for Reading Research, Florida State University, United States
| | - Jeanette Taylor
- Department of Psychology, Florida State University, United States
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Bates TC, Lewis GJ, Weiss A. Childhood socioeconomic status amplifies genetic effects on adult intelligence. Psychol Sci 2013; 24:2111-6. [PMID: 24002887 DOI: 10.1177/0956797613488394] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Studies of intelligence in children reveal significantly higher heritability among groups with high socioeconomic status (SES) than among groups with low SES. These interaction effects, however, have not been examined in adults, when between-families environmental effects are reduced. Using 1,702 adult twins (aged 24-84) for whom intelligence assessment data were available, we tested for interactions between childhood SES and genetic effects, between-families environmental effects, and unique environmental effects. Higher SES was associated with higher mean intelligence scores. Moreover, the magnitude of genetic influences on intelligence was proportional to SES. By contrast, environmental influences were constant. These results suggest that rather than setting lower and upper bounds on intelligence, genes multiply environmental inputs that support intellectual growth. This mechanism implies that increasing SES may raise average intelligence but also magnifies individual differences in intelligence.
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26
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Genotype by environment interactions in cognitive ability: a survey of 14 studies from four countries covering four age groups. Behav Genet 2013; 43:208-19. [PMID: 23397253 DOI: 10.1007/s10519-012-9581-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 12/17/2012] [Indexed: 10/27/2022]
Abstract
A large part of the variation in cognitive ability is known to be due to genetic factors. Researchers have tried to identify modifiers that influence the heritability of cognitive ability, indicating a genotype by environment interaction (G×E). To date, such modifiers include measured variables like income and socioeconomic status. The present paper focuses on G×E in cognitive ability where the environmental variable is an unmeasured environmental factor that is uncorrelated in family members. We examined this type of G×E in the GHCA-database (Haworth et al., Behav Genet 39:359-370, 2009), which comprises data of 14 different cognition studies from four different countries including participants of different ages. Results indicate that for younger participants (4-13 years), the strength of E decreases across the additive genetic factor A, but that this effect reverts for older participants (17-34 years). However, a clear and general conclusion about the presence of a genuine G×E is hampered by differences between the individual studies with respect to environmental and genetic influences on cognitive ability.
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27
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Hanscombe KB, Trzaskowski M, Haworth CMA, Davis OSP, Dale PS, Plomin R. Socioeconomic status (SES) and children's intelligence (IQ): in a UK-representative sample SES moderates the environmental, not genetic, effect on IQ. PLoS One 2012; 7:e30320. [PMID: 22312423 PMCID: PMC3270016 DOI: 10.1371/journal.pone.0030320] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 12/16/2011] [Indexed: 12/31/2022] Open
Abstract
Background The environment can moderate the effect of genes - a phenomenon called gene-environment (GxE) interaction. Several studies have found that socioeconomic status (SES) modifies the heritability of children's intelligence. Among low-SES families, genetic factors have been reported to explain less of the variance in intelligence; the reverse is found for high-SES families. The evidence however is inconsistent. Other studies have reported an effect in the opposite direction (higher heritability in lower SES), or no moderation of the genetic effect on intelligence. Methods Using 8716 twin pairs from the Twins Early Development Study (TEDS), we attempted to replicate the reported moderating effect of SES on children's intelligence at ages 2, 3, 4, 7, 9, 10, 12 and 14: i.e., lower heritability in lower-SES families. We used a twin model that allowed for a main effect of SES on intelligence, as well as a moderating effect of SES on the genetic and environmental components of intelligence. Results We found greater variance in intelligence in low-SES families, but minimal evidence of GxE interaction across the eight ages. A power calculation indicated that a sample size of about 5000 twin pairs is required to detect moderation of the genetic component of intelligence as small as 0.25, with about 80% power - a difference of 11% to 53% in heritability, in low- (−2 standard deviations, SD) and high-SES (+2 SD) families. With samples at each age of about this size, the present study found no moderation of the genetic effect on intelligence. However, we found the greater variance in low-SES families is due to moderation of the environmental effect – an environment-environment interaction. Conclusions In a UK-representative sample, the genetic effect on intelligence is similar in low- and high-SES families. Children's shared experiences appear to explain the greater variation in intelligence in lower SES.
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Affiliation(s)
- Ken B Hanscombe
- Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, United Kingdom.
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Detecting specific genotype by environment interactions using marginal maximum likelihood estimation in the classical twin design. Behav Genet 2011; 42:483-99. [PMID: 22146987 PMCID: PMC3350767 DOI: 10.1007/s10519-011-9522-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 11/23/2011] [Indexed: 11/10/2022]
Abstract
Considerable effort has been devoted to the analysis of genotype by environment (G × E) interactions in various phenotypic domains, such as cognitive abilities and personality. In many studies, environmental variables were observed (measured) variables. In case of an unmeasured environment, van der Sluis et al. (2006) proposed to study heteroscedasticity in the factor model using only MZ twin data. This method is closely related to the Jinks and Fulker (1970) test for G × E, but slightly more powerful. In this paper, we identify four challenges to the investigation of G × E in general, and specifically to the heteroscedasticity approaches of Jinks and Fulker and van der Sluis et al. We propose extensions of these approaches purported to solve these problems. These extensions comprise: (1) including DZ twin data, (2) modeling both A × E and A × C interactions; and (3) extending the univariate approach to a multivariate approach. By means of simulations, we study the power of the univariate method to detect the different G × E interactions in varying situations. In addition, we study how well we could distinguish between A × E, A × C, and C × E. We apply a multivariate version of the extended model to an empirical data set on cognitive abilities.
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van der Sluis S, Posthuma D, Dolan CV. A note on false positives and power in G × E modelling of twin data. Behav Genet 2011; 42:170-86. [PMID: 21748401 PMCID: PMC3253285 DOI: 10.1007/s10519-011-9480-3] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 06/14/2011] [Indexed: 11/30/2022]
Abstract
The variance components models for gene–environment interaction proposed by Purcell in 2002 are widely used. In both the bivariate and the univariate parameterization of these models, the variance decomposition of trait T is a function of moderator M. We show that if M and T are correlated, and moderator M is correlated between twins as well, the univariate parameterization produces a considerable increase in false positive moderation effects. A simple extension of this univariate moderation model prevents this elevation of the false positive rate provided the covariance between M and T is itself not also subject to moderation. If the covariance between M and T varies as a function of M, then moderation effects observed in the univariate setting should be interpreted with care as these can have their origin in either moderation of the covariance between M and T or in moderation of the unique paths of T. We conclude that researchers should use the full bivariate moderation model to study the presence of moderation on the covariance between M and T. If such moderation can be ruled out, subsequent use of the extended univariate moderation model, as proposed in this paper, is recommended as this model is more powerful than the full bivariate moderation model.
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Affiliation(s)
- Sophie van der Sluis
- Complex Trait Genetics, Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), FALW-VUA, Neuroscience Campus Amsterdam, VU University Medical Center (VUmc), Amsterdam, The Netherlands.
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Vasilopoulos T, Kremen WS, Kim K, Panizzon MS, Stein PK, Xian H, Grant MD, Lyons MJ, Toomey R, Eaves LJ, Franz CE, Jacobson KC. Untreated hypertension decreases heritability of cognition in late middle age. Behav Genet 2011; 42:107-20. [PMID: 21688193 DOI: 10.1007/s10519-011-9479-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 06/01/2011] [Indexed: 10/18/2022]
Abstract
Hypertension is a risk factor for cognitive decline, but the mechanisms underlying the effects of hypertension on cognition, particularly in midlife, are unclear. We examined whether hypertension modifies genetic influences on individual differences in cognition. Nine cognitive domains and general cognitive ability were assessed in a sample of 1,237 male twins aged 51-60 who were divided into three blood pressure groups: non-hypertensive; medicated hypertensive; and unmedicated hypertensive. Heritability was significantly lower among unmedicated hypertensives compared to medicated hypertensives and non-hypertensives for visual-spatial ability (p = 0.013) and episodic memory (p = 0.004). There were no heritability differences between non-hypertensives and medicated hypertensives. In addition, there were no significant differences in mean level cognition across the three blood pressure groups. These results suggest that in middle-aged men, untreated hypertension suppresses normal genetic influences on individual differences in certain domains of cognition prior to the emergence of hypertension-related effects on cognitive performance. These results further suggest that antihypertensive medication may protect against or reverse this effect.
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Affiliation(s)
- Terrie Vasilopoulos
- Department of Psychiatry & Behavioral Neuroscience, University of Chicago, 5841 S Maryland Ave, MC 3077, rm 603, Chicago, IL 60637, USA.
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Yeo RA, Gangestad SW, Liu J, Calhoun VD, Hutchison KE. Rare copy number deletions predict individual variation in intelligence. PLoS One 2011; 6:e16339. [PMID: 21298096 PMCID: PMC3027642 DOI: 10.1371/journal.pone.0016339] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 12/13/2010] [Indexed: 11/18/2022] Open
Abstract
Phenotypic variation in human intellectual functioning shows substantial heritability, as demonstrated by a long history of behavior genetic studies. Many recent molecular genetic studies have attempted to uncover specific genetic variations responsible for this heritability, but identified effects capture little variance and have proven difficult to replicate. The present study, motivated an interest in "mutation load" emerging from evolutionary perspectives, examined the importance of the number of rare (or infrequent) copy number variations (CNVs), and the total number of base pairs included in such deletions, for psychometric intelligence. Genetic data was collected using the Illumina 1MDuoBeadChip Array from a sample of 202 adult individuals with alcohol dependence, and a subset of these (N = 77) had been administered the Wechsler Abbreviated Scale of Intelligence (WASI). After removing CNV outliers, the impact of rare genetic deletions on psychometric intelligence was investigated in 74 individuals. The total length of the rare deletions significantly and negatively predicted intelligence (r = -.30, p = .01). As prior studies have indicated greater heritability in individuals with relatively higher parental socioeconomic status (SES), we also examined the impact of ethnicity (Anglo/White vs. Other), as a proxy measure of SES; these groups did not differ on any genetic variable. This categorical variable significantly moderated the effect of length of deletions on intelligence, with larger effects being noted in the Anglo/White group. Overall, these results suggest that rare deletions (between 5% and 1% population frequency or less) adversely affect intellectual functioning, and that pleotropic effects might partly account for the association of intelligence with health and mental health status. Significant limitations of this research, including issues of generalizability and CNV measurement, are discussed.
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Affiliation(s)
- Ronald A Yeo
- Department of Psychology, University of New Mexico, Albuquerque, New Mexico, United States of America.
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