Papers by Michelle Luciano
Polygenic risk for coronary artery disease is associated with cognitive ability in older adults
International Journal of Epidemiology, 2016
Coronary artery disease (CAD) is associated with cognitive decrements and risk of later dementia,... more Coronary artery disease (CAD) is associated with cognitive decrements and risk of later dementia, but it is not known if shared genetic factors underlie this association. We tested whether polygenic risk for CAD was associated with cognitive ability in community-dwelling cohorts of middle-aged and older adults. Individuals from Generation Scotland: Scottish Family Health Study (GS:SFHS, N = 9865) and from the Lothian Birth Cohorts of 1921 (LBC1921, N = 517) and 1936 (LBC1936, N = 1005) provided cognitive data and genome-wide genotype data. Polygenic risk profile scores for CAD were calculated for all of the cohorts using the largest available genome-wide association studies (GWAS) data set, the CARDIoGRAM consortium (22 233 cases and 64 762 controls). Polygenic risk profile scores for CAD were then tested for their association with cognitive abilities in the presence and absence of manifest cardiovascular disease. A meta-analysis of all three cohorts showed a negative association between CAD polygenic risk and fluid cognitive ability (β = -0.022, P = 0.016), verbal intelligence (β = -0.024, P = 0.011) and memory (β = -0.021, P = 0.028). Increased polygenic risk for CAD is associated with lower cognitive ability in older adults. Common genetic variants may underlie some of the association between age-related cognitive decrements and the risk for CAD.
J Invest Dermatol, 2005
Sun exposure has been known to cause histological changes in the dermal layer of the skin. Using ... more Sun exposure has been known to cause histological changes in the dermal layer of the skin. Using deterioration in the fine reticular patterning of the epidermal stratum corneum (skin pattern, as measured on the Beagley-Gibson scale) as a proxy measure of histological changes in the dermal layer, previous studies have typically assumed that degradation of skin pattern is largely caused by sun exposure. A twin study comprising 332 monozygotic twin pairs and 488 dizygotic twin pairs at ages 12, 14, and 16 was used to investigate the etiology of variation in skin pattern, particularly in relation to measured sun exposure and skin color. Our results indicate that although self-reported sun exposure is a significant contributor to variation in skin pattern, its effect is small, explaining only 3.4% of variation in skin pattern at age 14. Additive genetic effects explain 86% of variation in skin pattern at age 12 but these effects reduce with age so that 75% of variation is due to additive genetic effects at age 14 and 72% at age 16. This trend of diminishing genetic influences continues into adulthood, with 62% of variation due to non-additive genetic factors in a smaller adult sample (aged 32-86). Skin color explains 10.4% of variation in skin pattern at age 12, which is due to additive genetic influences common to both. Melanin content appears to provide a protective effect against skin pattern deterioration, perhaps because of the structural differences in melanosomes between different skin types or the free radical scavenging properties of melanin.
Modeling Parent of Origin Linkage Effects Using the IBD Mixture Distribution Approach
The progressive reduction of cognitive ability that emerges with aging is a result of complex int... more The progressive reduction of cognitive ability that emerges with aging is a result of complex interactions of genetic and environmental factors, whose nature and mechanisms still remain largely unknown. The main purpose of this study is to explore the relative contributions of genetic and environmental factors in determining interindividual variation of neurocognitive abilities as evaluated by a series of neuropsychological tests. A sample of 62-to 80-year-old twins, belonging to the population-based Italian Twin Registry, underwent a ...
Effects of Preferred Hand and Sex on the Perception of Tactile Simultaneity
J Clin Exp Neuropsychol, 2000
The effects of handedness, sex and the influence of hand placement in extrapersonal space on temp... more The effects of handedness, sex and the influence of hand placement in extrapersonal space on temporal information processing was investigated by measuring thresholds for perceiving the simultaneity of pairs of tactile stimuli. Simultaneity thresholds of preferred right handed and left handed university students with left hemisphere speech representation were compared using unimanual and bimanual stimulation at three hand placements (midline, lateral and crossed). In unimanual conditions two fingers of one hand were stimulated (single hemisphere), whereas in the bimanual conditions one finger of each hand was stimulated (cross hemispheres). Bimanual minus unimanual thresholds provided an estimate of interhemisphere transmission time (IHTT) regardless of hand placement. The effects of hemispace varied with the type of stimulation. With unimanual stimulation, overall thresholds were longer at the midline placement, however, with bimanual stimulation, thresholds were longer when the hands were spatially separated (crossed and/or uncrossed). Left handers' IHTTs were 8 ms faster than those of right handers. IHTTs in males were faster than females with hands placed in lateral (by 10.8 ms) or crossed (by 9.8 ms) but not midline positions. It was concluded that the cerebral hemispheres are equally capable of discriminating temporal intervals, but that the left hemisphere predominates when there is uncertainty about location of stimulation.
Personality and Individual Differences, Feb 29, 2008
This report is a response to Robinson's article (''Conceptual and methodological errors that inva... more This report is a response to Robinson's article (''Conceptual and methodological errors that invalidate Luciano et al.'s claim to have tested Robinson's theory of personality and intelligence''. )''. Our previous report of a linear rather than quadratic relationship between extraversion and IQ has been challenged by Robinson. In response to Robinson's queries, we have re-analysed our data using a more stringent classification of introverts, ambiverts and extraverts; these results are in line with our original finding. We have further tested the predictions Robinson derives from his theory taking into account neuroticism scores; we found little support for his predictions. A more comprehensive test of his theory will require the integration of EEG data.
Apolipoprotein E is not Related to Memory Abilities at 70�Years of Age
Behavior Genetics, 2009
APOE e4-related memory deficits were reported in a normal population aged between 50 and 60 when ... more APOE e4-related memory deficits were reported in a normal population aged between 50 and 60 when controlling for general cognitive ability in early adulthood. This extended findings of APOE e4 effects on cognitive ability in 60-80-year-olds to a younger group and confirmed that this effect relates to changes in memory ability with age. The present study tests the association of APOE e4 variation with verbal and spatial memory in a sample of 70-year-olds both adjusted and non-adjusted for childhood and adult general cognitive ability. The 1,013 participants comprise surviving members of the 1947 Scottish Mental Survey resident in the Lothian area of Scotland. They were tested on general cognitive ability at age 11 years and followed up at about age 70 with tests of verbal (immediate and delayed) and spatial memory. General linear models were used to test the association between variation in the APOE polymorphism (e4 presence vs. absence) and memory measures. Of the eight measures tested, Spatial span forward was significantly associated with APOE e4 variation (P = 0.04) when adjusting for IQ, whereas Logical memory immediate was associated with APOE e4 variation (P = 0.04) in the analysis not controlling for IQ. Neither of these tests was significant when a correction for multiple testing was applied. APOE e4 does not influence memory abilities in a normal population of 70-year-olds.
Genetic covariance between processing speed and IQ
Page 1. Genetic Covariance Between Processing Speed and IQ Michelle Luciano, Margaret J. Wright, ... more Page 1. Genetic Covariance Between Processing Speed and IQ Michelle Luciano, Margaret J. Wright, Glen A. Smith, Gina M. Geffen, Laurie B. Geffen, and Nicholas G. Martin Behavioral genetic studies of cognition have turned ...
was 56 years (SD=16.7) and of the females 60.7 years (SD=16.3). The data were collected between 1... more was 56 years (SD=16.7) and of the females 60.7 years (SD=16.3). The data were collected between 1991 and 2010. 3. BRESCIA -Italy. The Brescia cohort consisted of 177 unrelated healthy volunteers (89 female and screened for DSM-IV Axis I disorders by expert psychologists using the Mini-International Neuropsychiatric Interview (M.I.N.I.). Only healthy volunteers without a history of drug or alcohol abuse or dependence and without a personal or first-degree family history of psychiatric disorders were enrolled in the study. Subjects who obtained a score lower than 27/30 in the Mini Mental State Examination (M.M.S.E.) were excluded as well. Furthermore, only participants with Italian descent (all four grandparents Italian) could participate. The personality traits were assessed by the Italian version of the TCI, a 240-item, true-false self-report questionnaire. The mean age of the sample was 47.58 years (SD=16.30; women M=47.08, SD=17.31, men M=48.09, SD=15.29). The data were collected between 2007 and 2011.
Structural Brain MRI Trait Polygenic Score Prediction of Cognitive Abilities
Twin research and human genetics : the official journal of the International Society for Twin Studies, Jan 2, 2015
Structural brain magnetic resonance imaging (MRI) traits share part of their genetic variance wit... more Structural brain magnetic resonance imaging (MRI) traits share part of their genetic variance with cognitive traits. Here, we use genetic association results from large meta-analytic studies of genome-wide association (GWA) for brain infarcts (BI), white matter hyperintensities, intracranial, hippocampal, and total brain volumes to estimate polygenic scores for these traits in three Scottish samples: Generation Scotland: Scottish Family Health Study (GS:SFHS), and the Lothian Birth Cohorts of 1936 (LBC1936) and 1921 (LBC1921). These five brain MRI trait polygenic scores were then used to: (1) predict corresponding MRI traits in the LBC1936 (numbers ranged 573 to 630 across traits), and (2) predict cognitive traits in all three cohorts (in 8,115-8,250 persons). In the LBC1936, all MRI phenotypic traits were correlated with at least one cognitive measure, and polygenic prediction of MRI traits was observed for intracranial volume. Meta-analysis of the correlations between MRI polygeni...
W e assessed the heritability of head circumference, an approximation of brain size, in twin-sib ... more W e assessed the heritability of head circumference, an approximation of brain size, in twin-sib families of different ages. Data from the youngest participants were collected a few weeks after birth and from the oldest participants around age 50 years. In nearly all age groups the largest part of the variation in head circumference was explained by genetic differences. Heritability estimates were 90% in young infants (4 to 5 months), 85-88% in early childhood, 83-87% in adolescence, 75% in young and mid adulthood. In infants younger than 3 months, heritability was very low or absent. Quantitative sex differences in heritability were observed in 15-and 18-year-olds, but there was no evidence for qualitative sex differences, that is, the same genes were expressed in both males and females. Longitudinal analysis of the data between 5, 7, and 18 years of age showed high genetic stability (.78 > R G > .98). These results indicate that head circumference is a highly heritable biometric trait and a valid target for future GWA studies.
Meta-analysis of Genome-Wide Association Studies for Extraversion: Findings from the Genetics of Personality Consortium
Behavior genetics, Jan 11, 2015
Extraversion is a relatively stable and heritable personality trait associated with numerous psyc... more Extraversion is a relatively stable and heritable personality trait associated with numerous psychosocial, lifestyle and health outcomes. Despite its substantial heritability, no genetic variants have been detected in previous genome-wide association (GWA) studies, which may be due to relatively small sample sizes of those studies. Here, we report on a large meta-analysis of GWA studies for extraversion in 63,030 subjects in 29 cohorts. Extraversion item data from multiple personality inventories were harmonized across inventories and cohorts. No genome-wide significant associations were found at the single nucleotide polymorphism (SNP) level but there was one significant hit at the gene level for a long non-coding RNA site (LOC101928162). Genome-wide complex trait analysis in two large cohorts showed that the additive variance explained by common SNPs was not significantly different from zero, but polygenic risk scores, weighted using linkage information, significantly predicted ex...
Current Versus Lifetime Depression, APOE Variation, and Their Interaction on Cognitive Performance in Younger and Older Adults
Psychosomatic medicine, Jan 28, 2015
An interaction effect of depressive symptoms and APOE e4 allele status on cognitive decline has b... more An interaction effect of depressive symptoms and APOE e4 allele status on cognitive decline has been shown in old age: e4 allele carriers with more depressive symptoms have faster cognitive decline than those with either depression or the e4 allele. We test this interaction effect on four cognitive domains, using a clinical depression measure comparing current versus lifetime depression. 14,379 individuals aged 18 to 59 years, and 3944 individuals aged 60 to 94 years from the Generation Scotland: Scottish Family Health Study participated. Linear-mixed models-accounting for participant relatedness and demographic and health indices-tested for effects of depression and APOE on cognitive abilities. There was no interaction between depression and APOE on cognition (p > .05). Current depression was associated with poorer speed (in both groups) and memory (18- to 59-year-olds); differences ranged from 0.01 to 0.03 standard deviation [SD]. For lifetime depression, cognitive performance ...
Meta-analysis of Genome-wide Association Studies for Neuroticism, and the Polygenic Association With Major Depressive Disorder
JAMA psychiatry, Jan 20, 2015
Neuroticism is a pervasive risk factor for psychiatric conditions. It genetically overlaps with m... more Neuroticism is a pervasive risk factor for psychiatric conditions. It genetically overlaps with major depressive disorder (MDD) and is therefore an important phenotype for psychiatric genetics. The Genetics of Personality Consortium has created a resource for genome-wide association analyses of personality traits in more than 63 000 participants (including MDD cases). To identify genetic variants associated with neuroticism by performing a meta-analysis of genome-wide association results based on 1000 Genomes imputation; to evaluate whether common genetic variants as assessed by single-nucleotide polymorphisms (SNPs) explain variation in neuroticism by estimating SNP-based heritability; and to examine whether SNPs that predict neuroticism also predict MDD. Genome-wide association meta-analysis of 30 cohorts with genome-wide genotype, personality, and MDD data from the Genetics of Personality Consortium. The study included 63 661 participants from 29 discovery cohorts and 9786 partic...
Behavior genetics, 2001
The genetic relationship between lower (information processing speed), intermediate (working memo... more The genetic relationship between lower (information processing speed), intermediate (working memory), and higher levels (complex cognitive processes as indexed by IQ) of mental ability was studied in a classical twin design comprising 166 monozygotic and 190 dizygotic twin pairs. Processing speed was measured by a choice reaction time (RT) task (2-, 4-, and 8-choice), working memory by a visual-spatial delayed response task, and IQ by the Multidimensional Aptitude Battery. Multivariate analysis, adjusted for test-retest reliability, showed the presence of a genetic factor influencing all variables and a genetic factor influencing 4- and 8-choice RTs, working memory, and IQ. There were also genetic factors specific to 8-choice RT, working memory, and IQ. The results confirmed a strong relationship between choice RT and IQ (phenotypic correlations: -0.31 to -0.53 in females, -0.32 to -0.56 in males; genotypic correlations: -0.45 to -0.70) and a weaker but significant association betwe...
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Papers by Michelle Luciano