OBJECTIVE Illness behaviors-or responses to bodily symptoms-predict individuals' recovery and... more OBJECTIVE Illness behaviors-or responses to bodily symptoms-predict individuals' recovery and functioning; however, there has been little research on the early life personality antecedents of illness behavior. This study's primary aims were to evaluate (a) childhood temperament traits (i.e., emotionality and sociability) as predictors of adult illness behaviors, independent of objective health; and (b) adult temperament traits for mediation of childhood temperament's associations. METHOD Participants included 714 (53% male; 350 adoptive family and 364 control family) children and siblings from the Colorado Adoption Project (CAP; Plomin & DeFries, 1983). Structural regression analyses evaluated paths from childhood temperament to illness behavior (i.e., somatic complaints, sick days, and medication use) at two adulthood assessments (CAP years 21 and 30). Analyses controlled for participant age, sex, family type (adoptive or control), adopted status, parent education/occupation, and middle childhood illnesses, doctor visits, and life events stress. RESULTS Latent illness behavior factors were established across 2 adulthood assessments. Multilevel path analyses revealed that higher emotionality (fearfulness) in adulthood-but not childhood temperament-predicted higher levels of illness behavior at both assessments. Lastly, lower emotionality-fearfulness partially mediated the effect of higher childhood sociability on adult illness behavior. CONCLUSIONS Results suggest the importance of childhood illness experiences and adult emotionality (fearfulness) in shaping illness behavior in early adulthood. They also suggest a small, protective role of childhood sociability on reduced trait fearfulness in adulthood. These findings broaden our understanding of the prospective links between temperament and illness behavior development, suggesting distinct associations from early life illness experiences. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
The ε4 allele of APOE is a well-established genetic risk factor for cognitive aging and dementia,... more The ε4 allele of APOE is a well-established genetic risk factor for cognitive aging and dementia, although its influence on early life cognition is unknown. Consequently, we assessed associations of APOE genotypes with cognitive performance during 7, 12 and 16 year-assessments in our ongoing Colorado Adoption/Twin Study of Lifespan behavioral development (CATSLife). In general, APOE ε4 was associated with lower Verbal, Performance and Full Scale IQ scores during childhood and adolescence (e.g., Full Scale IQ was lower by 1.91 points per ε4 allele, d = −.13), with larger effects in females (e.g., average Full Scale IQ scores were 3.41 points lower in females per each ε4 allele, versus .33 points lower in males). Thus, these results suggest that deleterious effects of the APOE ε4 allele are manifested prior to adulthood, especially in females, and support both early origin theories and differential life-course vulnerabilities for later cognitive impairment.
The Journals of Gerontology: Series B, Jul 22, 2023
Objectives Frailty is not an end state of aging, but rather represents physiological vulnerabilit... more Objectives Frailty is not an end state of aging, but rather represents physiological vulnerability across multiple systems that unfolds across adulthood. However, examinations of frailty at the midlife transition, and how frailty may impact other age-sensitive traits, such as processing speed (PS) remain scarce. Our research aims were to examine frailty and frailty-speed associations before midlife, a ripe developmental period for healthy aging interventions. Method Using data from the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife1; N=1215; Mage=33.23 years; SD=4.98), we constructed 25-item (FI25) and 30-item (FI30) frailty indices. PS was measured using the Colorado Perceptual Speed (CPS) task and WAIS-III Digit Symbol (DS) subtest. Multilevel models accounted for clustering among siblings and adjusted for sex, race, ethnicity, adoption status, educational attainment, and age. Results Reliability of FI measures was apparent from strong intraclass correlations (ICCs) among identical twin siblings, while ICC patterns across all siblings suggested that FI variability may include non-additive genetic contributions. Higher FI was associated with poorer PS performance but was significant for DS only (BFI25=-1.17, p=.001, d=-0.12; BFI30=-1.23, p=.0007, d=-0.12). Furthermore, the negative frailty-DS association was moderated by age (BFI25xAge=-0.14, p=.042; BFI30xAge=-0.19, p=.008) where increasingly worse performance with higher frailty emerged at older ages. Discussion Frailty is evident before midlife and associated with poorer PS, an association that magnifies with age. These findings help elucidate the interrelationship between indicators of frailty and cognitive performance for adults approaching midlife, an understudied period within lifespan development.
International Journal of Behavioral Development, Jun 1, 1999
Results obtained from longitudinal studies suggest that individual differences in reading perform... more Results obtained from longitudinal studies suggest that individual differences in reading performance are relatively stable over time. However, the aetiology of this stability has not been previously explored. In the current study, the aetiology of longitudinal stability of reading performance between 7 and 12 years of age was assessed using data from adoptive (97 unrelated sibling pairs at age 7 and 73 pairs at age 12) and nonadoptive (106 related pairs at age 7 and 75 pairs at age 12) children tested in the Colorado Adoption Project. Results of a bivariate behavioural genetic analysis confirmed earlier findings of moderate genetic influence on individual differences in reading performance at both 7 and 12 years of age ( h2 = .49 and .37, respectively). Moreover, about 70% of the observed stability ( r = .61) between the two ages was due to common genetic influences. Of special interest, no new heritable or shared environmental variation was manifested at age 12, suggesting that the same genetic and shared environmental influences were operating at both ages. In contrast, nonshared environmental influences (e.g. instructional methods, teachers, peers, etc.) were responsible for change between 7 and 12 years of age, indicating the salience of such factors for the development of reading performance between middle childhood and adolescence.
Cognitive reserve (CR) refers to adaptability allowing for better cognitive outcomes given the de... more Cognitive reserve (CR) refers to adaptability allowing for better cognitive outcomes given the degree of brain changes or other risk factors for cognitive decline. Despite significant research efforts, our knowledge of cognitive reserve proxies remains limited. Studies predominantly use a single sociodemographic variable (e.g., education attainment) as a proxy measure when CR can manifest in multiple domains. Studies also tend to rely on older samples, whereas adversity factors of cognitive performance may have differing onset ages, suggesting different risk or protective mechanisms at different ages. We examine two cohort datasets spanning from early adolescence (Adolescent Brain Cognitive Development study, N = 5559) up to the cusp of mid-adulthood (Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging; CATSLife, N = 1327) to evaluate the role of CR proxies across over 100 variables. Defined as a moderator between a cognitive outcome and structural br...
Journal of the American Academy of Child & Adolescent Psychiatry, 2022
OBJECTIVE To investigate the genetic architecture of internalizing symptoms in childhood and adol... more OBJECTIVE To investigate the genetic architecture of internalizing symptoms in childhood and adolescence. METHOD In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children aged between 3 and 18. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age and instrument. RESULTS The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphisms (SNP) heritability (1.66%, 95% confidence intervals 0.84-2.48%, neffective=132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% confidence intervals 3.08-8.18%). Additive genetic effects on internalizing symptoms appeared stable over age, with overlapping estimates of SNP heritability from early-childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the wellbeing spectrum (|rg|> 0.70), as well as with insomnia, loneliness, attention-deficit hyperactivity disorder, autism, and childhood aggression (range |rg|=0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa. CONCLUSION Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity amongst childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.
Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the ... more Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the U.S. were explored in a genetically sensitive design (max. N = 627 preschool pairs and 422 kindergarten pairs). Analyses indicated a strong genetic influence on preschool phonological awareness, rapid naming, and verbal memory. Print awareness, vocabulary and grammar/morphology were subject primarily to shared environment effects. There were significant genetic and shared environment correlations among the preschool traits, as well as effects that were particular to each variable. Kindergarten reading, phonological awareness and rapid naming were primarily affected by genes, with spelling equally affected by genes and shared environment. Multivariate analyses revealed genetic and environmental overlap and independence among kindergarten variables. Longitudinal analyses showed genetic continuity as well as change in phonological awareness and rapid naming across the 2 years. Relations amo...
OBJECTIVE Illness behaviors-or responses to bodily symptoms-predict individuals' recovery and... more OBJECTIVE Illness behaviors-or responses to bodily symptoms-predict individuals' recovery and functioning; however, there has been little research on the early life personality antecedents of illness behavior. This study's primary aims were to evaluate (a) childhood temperament traits (i.e., emotionality and sociability) as predictors of adult illness behaviors, independent of objective health; and (b) adult temperament traits for mediation of childhood temperament's associations. METHOD Participants included 714 (53% male; 350 adoptive family and 364 control family) children and siblings from the Colorado Adoption Project (CAP; Plomin & DeFries, 1983). Structural regression analyses evaluated paths from childhood temperament to illness behavior (i.e., somatic complaints, sick days, and medication use) at two adulthood assessments (CAP years 21 and 30). Analyses controlled for participant age, sex, family type (adoptive or control), adopted status, parent education/occupation, and middle childhood illnesses, doctor visits, and life events stress. RESULTS Latent illness behavior factors were established across 2 adulthood assessments. Multilevel path analyses revealed that higher emotionality (fearfulness) in adulthood-but not childhood temperament-predicted higher levels of illness behavior at both assessments. Lastly, lower emotionality-fearfulness partially mediated the effect of higher childhood sociability on adult illness behavior. CONCLUSIONS Results suggest the importance of childhood illness experiences and adult emotionality (fearfulness) in shaping illness behavior in early adulthood. They also suggest a small, protective role of childhood sociability on reduced trait fearfulness in adulthood. These findings broaden our understanding of the prospective links between temperament and illness behavior development, suggesting distinct associations from early life illness experiences. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
The ε4 allele of APOE is a well-established genetic risk factor for cognitive aging and dementia,... more The ε4 allele of APOE is a well-established genetic risk factor for cognitive aging and dementia, although its influence on early life cognition is unknown. Consequently, we assessed associations of APOE genotypes with cognitive performance during 7, 12 and 16 year-assessments in our ongoing Colorado Adoption/Twin Study of Lifespan behavioral development (CATSLife). In general, APOE ε4 was associated with lower Verbal, Performance and Full Scale IQ scores during childhood and adolescence (e.g., Full Scale IQ was lower by 1.91 points per ε4 allele, d = −.13), with larger effects in females (e.g., average Full Scale IQ scores were 3.41 points lower in females per each ε4 allele, versus .33 points lower in males). Thus, these results suggest that deleterious effects of the APOE ε4 allele are manifested prior to adulthood, especially in females, and support both early origin theories and differential life-course vulnerabilities for later cognitive impairment.
The Journals of Gerontology: Series B, Jul 22, 2023
Objectives Frailty is not an end state of aging, but rather represents physiological vulnerabilit... more Objectives Frailty is not an end state of aging, but rather represents physiological vulnerability across multiple systems that unfolds across adulthood. However, examinations of frailty at the midlife transition, and how frailty may impact other age-sensitive traits, such as processing speed (PS) remain scarce. Our research aims were to examine frailty and frailty-speed associations before midlife, a ripe developmental period for healthy aging interventions. Method Using data from the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife1; N=1215; Mage=33.23 years; SD=4.98), we constructed 25-item (FI25) and 30-item (FI30) frailty indices. PS was measured using the Colorado Perceptual Speed (CPS) task and WAIS-III Digit Symbol (DS) subtest. Multilevel models accounted for clustering among siblings and adjusted for sex, race, ethnicity, adoption status, educational attainment, and age. Results Reliability of FI measures was apparent from strong intraclass correlations (ICCs) among identical twin siblings, while ICC patterns across all siblings suggested that FI variability may include non-additive genetic contributions. Higher FI was associated with poorer PS performance but was significant for DS only (BFI25=-1.17, p=.001, d=-0.12; BFI30=-1.23, p=.0007, d=-0.12). Furthermore, the negative frailty-DS association was moderated by age (BFI25xAge=-0.14, p=.042; BFI30xAge=-0.19, p=.008) where increasingly worse performance with higher frailty emerged at older ages. Discussion Frailty is evident before midlife and associated with poorer PS, an association that magnifies with age. These findings help elucidate the interrelationship between indicators of frailty and cognitive performance for adults approaching midlife, an understudied period within lifespan development.
International Journal of Behavioral Development, Jun 1, 1999
Results obtained from longitudinal studies suggest that individual differences in reading perform... more Results obtained from longitudinal studies suggest that individual differences in reading performance are relatively stable over time. However, the aetiology of this stability has not been previously explored. In the current study, the aetiology of longitudinal stability of reading performance between 7 and 12 years of age was assessed using data from adoptive (97 unrelated sibling pairs at age 7 and 73 pairs at age 12) and nonadoptive (106 related pairs at age 7 and 75 pairs at age 12) children tested in the Colorado Adoption Project. Results of a bivariate behavioural genetic analysis confirmed earlier findings of moderate genetic influence on individual differences in reading performance at both 7 and 12 years of age ( h2 = .49 and .37, respectively). Moreover, about 70% of the observed stability ( r = .61) between the two ages was due to common genetic influences. Of special interest, no new heritable or shared environmental variation was manifested at age 12, suggesting that the same genetic and shared environmental influences were operating at both ages. In contrast, nonshared environmental influences (e.g. instructional methods, teachers, peers, etc.) were responsible for change between 7 and 12 years of age, indicating the salience of such factors for the development of reading performance between middle childhood and adolescence.
Cognitive reserve (CR) refers to adaptability allowing for better cognitive outcomes given the de... more Cognitive reserve (CR) refers to adaptability allowing for better cognitive outcomes given the degree of brain changes or other risk factors for cognitive decline. Despite significant research efforts, our knowledge of cognitive reserve proxies remains limited. Studies predominantly use a single sociodemographic variable (e.g., education attainment) as a proxy measure when CR can manifest in multiple domains. Studies also tend to rely on older samples, whereas adversity factors of cognitive performance may have differing onset ages, suggesting different risk or protective mechanisms at different ages. We examine two cohort datasets spanning from early adolescence (Adolescent Brain Cognitive Development study, N = 5559) up to the cusp of mid-adulthood (Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging; CATSLife, N = 1327) to evaluate the role of CR proxies across over 100 variables. Defined as a moderator between a cognitive outcome and structural br...
Journal of the American Academy of Child & Adolescent Psychiatry, 2022
OBJECTIVE To investigate the genetic architecture of internalizing symptoms in childhood and adol... more OBJECTIVE To investigate the genetic architecture of internalizing symptoms in childhood and adolescence. METHOD In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children aged between 3 and 18. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age and instrument. RESULTS The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphisms (SNP) heritability (1.66%, 95% confidence intervals 0.84-2.48%, neffective=132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% confidence intervals 3.08-8.18%). Additive genetic effects on internalizing symptoms appeared stable over age, with overlapping estimates of SNP heritability from early-childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the wellbeing spectrum (|rg|> 0.70), as well as with insomnia, loneliness, attention-deficit hyperactivity disorder, autism, and childhood aggression (range |rg|=0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa. CONCLUSION Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity amongst childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.
Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the ... more Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the U.S. were explored in a genetically sensitive design (max. N = 627 preschool pairs and 422 kindergarten pairs). Analyses indicated a strong genetic influence on preschool phonological awareness, rapid naming, and verbal memory. Print awareness, vocabulary and grammar/morphology were subject primarily to shared environment effects. There were significant genetic and shared environment correlations among the preschool traits, as well as effects that were particular to each variable. Kindergarten reading, phonological awareness and rapid naming were primarily affected by genes, with spelling equally affected by genes and shared environment. Multivariate analyses revealed genetic and environmental overlap and independence among kindergarten variables. Longitudinal analyses showed genetic continuity as well as change in phonological awareness and rapid naming across the 2 years. Relations amo...
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Papers by Sally Wadsworth