Twin Study of the Relationship between Childhood Negative Emotionality and Hyperactivity/Inattention Problems

AbstractThe present study aimed to determine the genetic and environmental etiology of the association between childhood negative emotionality (NE) and hyperactivity/inattention problems (HIP) using South Korean elementary school twins (mean age = 10.19 years, SD = 1.79 years). Telephone interviews were given to mothers of 919 twins (229 monozygotic males: 112 pairs and 5 individuals; 148 dizygotic males: 73 pairs and 2 individuals; 180 monozygotic females: 87 pairs and 6 individuals; 103 dizygotic females: 50 pairs and 3 individuals; 259 opposite-sex dizygotic twins: 127 pairs and 5 individuals) to assess their children’s NE and HIP. Consistent with prior studies, the phenotypic correlation between NE and the HIP was moderate (r = .29; 95% CI = .24, .34). Model-fitting analysis revealed that additive genetic and nonshared environmental influences on NE were .45 (95% CI [.34, .54]) and .55 (95% CI [.46, .66]), respectively, and that additive and nonadditive genetic, and nonshared environmental influences on HIP were .08 (95% CI [.03, .26]), .41 (95% CI [.21, .51]) and .51 (95% CI = .42, .61), respectively. In addition, the additive genetic correlation between NE and HIP was 1.0 (95% CI [.52, 1.00]), indicating that additive genetic factors are entirely shared between the two phenotypes. Nonadditive genetic influences were unique to HIP and not responsible for the NE-HIP association. Nonshared environmental correlation was significant but modest (re = .18, 95% CI [.06, .30]).

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Heritability of Hwabyung Symptoms in South Korean Adolescent and Young Adult Twins

Twin Research and Human Genetics ◽

10.1017/thg.2018.40 ◽

2018 ◽

Vol 21 (5) ◽

pp. 378-383 ◽

Cited By ~ 3

Author(s):

Yoon-Mi Hur ◽

Eun-ji Choi ◽

Jong-Woo Kim ◽

Hee-Jeong Jin ◽

Siwoo Lee

Keyword(s):

Young Adult ◽

Environmental Influences ◽

Model Fitting ◽

Adolescent And Young Adult ◽

Parameter Estimates ◽

Present Sample ◽

South Korean ◽

Opposite Sex ◽

Estimate Heritability ◽

Adult Twins

The present study aimed to estimate heritability of Hwabyung (HB) symptoms in adolescent and young adult twins in South Korea. The sample included 1,601 twins consisting of 143 pairs of monozygotic male (MZM), 67 pairs of dizygotic male (DZM), 295 pairs of monozygotic female (MZF), 114 pairs of dizygotic female (DZF), and 117 pairs of opposite-sex dizygotic (OSDZ) twins and 129 twins with non-participating co-twins (mean age = 19.1 ± 3.1 years; range: 12–29 years). An HB symptom questionnaire was given to twins via a telephone interview. Consistent with the literature of HB, the mean level of HB was significantly higher in females than in males. Maximum likelihood twin correlations for HB were 0.31 (95% CI [0.16, 0.45]) for MZM, 0.19 (95% CI [-0.05, 0.41]) for DZM, 0.50 (95% CI [0.41, 0.58]) for MZF, 0.28 (95% CI [0.11, 0.44]) for DZF, and 0.23 (95% CI [0.05, 0.40]) for OSDZ twins. These patterns of twin correlations suggested the presence of additive genetic influences on HB. Model-fitting analysis showed that additive genetic and individual-specific environmental influences on HB were 44% (95% CI [37, 51]) and 56% (95% CI [49, 63]), respectively. Shared environmental influences were not significant. These parameter estimates were not significantly different between two sexes, and did not change significantly with age in the present sample, suggesting that genetic and environmental influences on HB in both sexes are stable across adolescence and young adulthood.

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Genetic and Environmental Etiology of the Relationship Between Childhood Hyperactivity/Inattention and Conduct Problems in a South Korean Twin Sample

Twin Research and Human Genetics ◽

10.1017/thg.2015.26 ◽

2015 ◽

Vol 18 (3) ◽

pp. 290-297 ◽

Cited By ~ 5

Author(s):

Yoon-Mi Hur

Keyword(s):

Conduct Problems ◽

Genetic Factors ◽

Additive Genetic Variance ◽

Model Fitting ◽

Twin Studies ◽

Phenotypic Correlation ◽

Comorbid Condition ◽

Bivariate Model ◽

New Finding ◽

The Relationship

Recently, there has been increased research into the etiology of the comorbidity between hyperactivity/inattention problems (HIP) and conduct problems (CP). However, the nature of the etiology of the comorbidity has remained unclear. Mothers of 507 pairs of twins, comprised of 221 monozygotic (MZ) and 286 dizygotic (DZ) twin pairs aged from 6 to 13 years (mean = 9.6 years; SD = 2.0 years), completed the HIP and the CP scale of the Strengths and Difficulties Questionnaire (SDQ) via a telephone interview. The phenotypic correlation between HIP and CP was 0.43 (p < .01). MZ and DZ twin correlations were, respectively, 0.48 (95%CI: 0.37–0.58) and 0.06 (95%CI: -0.06–0.19) for HIP and 0.38 (95%CI: 0.26–0.49) and 0.35 (95%CI: 0.25–0.45) for CP. The bivariate model-fitting results revealed additive genetic correlation of 1.0 (95% CI: 0.72–1.00), a complete overlap of additive genetic variance component between HIP and CP, supporting the importance of correlated additive genetic risk factors for the comorbid condition of HIP and CP. HIP was additionally influenced by non-additive genetic factors that did not contribute to the relationship between HIP and CP. There was a significant but moderate child-specific environmental correlation (re = 0.37) between HIP and CP. CP was additionally influenced by shared family environmental influences. While the results of the present study are generally consistent with the findings from Western twin studies of the relationship between HIP and CP, they add a new finding to the extant literature by showing that it is additive rather than non-additive genetic factors that are responsible for the co-occurrence of HIP and CP.

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Heritability of Age at Menarche in South Korean Female Twins

Twin Research and Human Genetics ◽

10.1017/thg.2019.17 ◽

2019 ◽

Vol 22 (03) ◽

pp. 183-186 ◽

Cited By ~ 2

Author(s):

Yoon-Mi Hur ◽

Hee-Jeong Jin ◽

Siwoo Lee

Keyword(s):

Maximum Likelihood ◽

Environmental Effects ◽

Environmental Influences ◽

Model Fitting ◽

Total Sample ◽

Age At Menarche ◽

South Korean ◽

Opposite Sex ◽

The Mean ◽

Mz Twins

AbstractGenetic and environmental influences on age at menarche (AAM) have rarely been examined in Asian females. This study aimed to investigate the heritability of AAM in South Korean female twins. The AAM data from 1370 female twins (933 monozygotic [MZ] twins, 294 dizygotic [DZ] twins and 160 female members of opposite-sex DZ twins) born between 1988 and 2001 were analyzed. The age of the sample at the time of the assessment ranged from 16 to 28 years with a mean of 19.3 (SD = 2.2) years. The mean AAM in the total sample was 12.49 (SD = 1.41) years. Although the mean AAM decreased with increasing birth years, it levelled off in birth years 2000–2001. Maximum likelihood MZ and DZ twin correlations were 0.72 [95% CI (0.67, 0.76)] and 0.35 [95% CI (0.19, 0.50)], respectively. The results of model-fitting analysis indicated that the additive genetic and individual-specific environmental effects were 72% [95% CI (67%, 76%)] and 28% [95% CI (24%, 33%)], respectively. Neither nonadditive genetic nor shared environmental effects were significant.

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Increasing Relationship Between Negative Emotionality and Conduct Problems During Childhood: A Cross-Sectional Behavioral Genetic Analysis

Twin Research and Human Genetics ◽

10.1017/thg.2015.70 ◽

2015 ◽

Vol 18 (6) ◽

pp. 785-792 ◽

Cited By ~ 1

Author(s):

Yoon-Mi Hur ◽

Sunyung Hwang ◽

Un-Sun Chung

Keyword(s):

Elementary School ◽

Conduct Problems ◽

School Children ◽

Elementary School Children ◽

Genetic Factors ◽

Negative Emotionality ◽

Phenotypic Correlation ◽

Age Difference ◽

Older Children ◽

The Relationship

Age difference in the etiology of the relationship between childhood negative emotionality (NE) and conduct problems (CP) has not been previously investigated. Mothers of 662 pairs of twins completed questions on the emotionality (NE) scale of the EAS temperament survey and the CP scale of the Strengths and Difficulties Questionnaires (SDQ) via a telephone interview. Twin data were analyzed separately in younger (ages 3 to 7 years; mostly pre-schoolers) and older children (ages 8 to 13 years; mostly elementary school children). The phenotypic correlation between NE and CP increased from 0.33 among younger twins to 0.43 among older twins. Bivariate model-fitting analysis was performed to determine age difference in the etiology of the relationship between NE and CP. Among younger twins, the correlation between NE and CP was entirely explained by additive genetic factors common to NE and CP. Among older children, however, a small but significant amount of unique environmental correlation emerged to account for about 47% of the phenotypic correlation between NE and CP. The remaining 53% of the phenotypic correlation was due to shared additive genetic factors. We speculate that environmental factors associated with school adjustment may exert influences on the relationship between NE and CP among elementary school children.

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Association between symptoms of sleep apnea and problem behaviors in young adult twins and siblings

Psychological Medicine ◽

10.1017/s0033291719004070 ◽

2020 ◽

pp. 1-8

Author(s):

Juan J. Madrid-Valero ◽

Nicola L. Barclay ◽

Richard Rowe ◽

Rotem Perach ◽

Daniel J. Buysse ◽

...

Keyword(s):

Sleep Apnea ◽

Problem Behaviors ◽

Externalizing Problems ◽

Genetic Factors ◽

Externalizing Behaviors ◽

Environmental Influences ◽

Significant Proportion ◽

Symptoms Of Depression ◽

Adult Twins ◽

The Relationship

Abstract Background Sleep apnea is one of the most common sleep disorders and it is related to multiple negative health consequences. Previous studies have shown that sleep apnea is influenced by genetic factors. However, studies have not investigated the genetic and environmental influences of symptoms of sleep apnea in young adults. Furthermore, the underpinnings of the relationship between apnea symptoms and internalizing/externalizing problems are unknown. The objectives of this study were to estimate the magnitude of: (1) genetic and environmental influences on self-reported apnea symptoms; (2) the relationship between self-reported apnea symptoms and internalizing/externalizing traits; (3) genetic and environmental influences on the associations between self-reported apnea symptoms, internalizing behaviors and externalizing behaviors. Methods In a twin/sibling study, univariate and multivariate models were fitted to estimate both individual variance and sources of covariance between symptoms of sleep apnea and internalizing/externalizing behaviors. Results Our results show that genetic influences account for 40% of the variance in sleep apnea symptoms. Moreover, there are modest associations between depression, anxiety and externalizing behaviors with apnea symptoms (ranging from r = 0.22–0.29). However, the origins of these associations differ. For example, whereas most of the covariation between symptoms of depression and sleep apnea can be explained by genes (95%), there was a larger role for the environment (53%) in the association between symptoms of anxiety and sleep apnea. Conclusions Genetic factors explain a significant proportion of variance in symptoms of apnea and most of the covariance with depression.

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Religious Attendance Moderates the Environmental Effect on Prosocial Behavior in Nigerian Adolescents

Twin Research and Human Genetics ◽

10.1017/thg.2018.71 ◽

2019 ◽

Vol 22 (1) ◽

pp. 42-47 ◽

Cited By ~ 6

Author(s):

Yoon-Mi Hur ◽

Hoe-Uk Jeong ◽

Frances Ajose ◽

Ariel Knafo-Noam

Keyword(s):

Prosocial Behavior ◽

Environmental Influences ◽

Model Fitting ◽

Interaction Model ◽

Genetic Effects ◽

Religious Attendance ◽

Phenotypic Correlation ◽

Phenotypic Variance ◽

Environmental Variance ◽

Frequent Attenders

AbstractThere is a growing body of literature linking religious attendance to prosocial behavior (PB). The main purposes of the present study were to estimate genetic and environmental influences on the frequency of religious attendance (FRA) and to explore whether and how FRA moderates genetic and/or environmental influences on PB. As part of the Nigerian Twin and Sibling Study, 2860 (280 monozygotic male, 417 monozygotic female, 544 dizygotic male, 699 dizygotic female, and 920 opposite-sex dizygotic) twins (mean age = 14.2 years; SD = 1.7 years; age range = 12–18 years) completed a questionnaire regarding FRA and a PB scale. Similar to the findings from western twin samples, FRA showed substantial shared environmental influences of 74% (95% CI = 69%, 78%), with absence of genetic effects. The phenotypic correlation between FRA and PB was modest but positive and significant (r = .12; p < .01), suggesting that PB is higher among more frequent attenders than among less frequent attenders. The results of gene–environment (G × E) interaction model-fitting analysis revealed that FRA changed individual environmental experiences rather than genetic effects on PB such that while genetic variance was stable, non-shared environmental variance declined, leading the total phenotypic variance of PB to decrease with increasing levels of religious attendance.

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Shared Genetic Etiology of Hwabyung (Anger Syndrome) and Somatization Symptoms in South Korean Adolescent and Young Adult Twins

Twin Research and Human Genetics ◽

10.1017/thg.2019.6 ◽

2019 ◽

Vol 22 (2) ◽

pp. 114-119 ◽

Cited By ~ 2

Author(s):

Yoon-Mi Hur ◽

Hee-Jeong Jin ◽

Siwoo Lee ◽

Jong-Woo Kim

Keyword(s):

Young Adult ◽

Measurement Error ◽

Genetic Factors ◽

Environmental Influences ◽

Adolescent And Young Adult ◽

Genetic Etiology ◽

Environmental Variance ◽

South Korean ◽

Korean Adolescent ◽

Shared Genetic

AbstractSomatization is known to be more prevalent in Asian than in Western populations. Using a South Korean adolescent and young adult twin sample (N = 1754; 367 monozygotic male, 173 dizygotic male, 681 monozygotic female, 274 dizygotic female and 259 opposite-sex dizygotic twins), the present study aimed to estimate heritability of somatization and to determine common genetic and environmental influences on somatization and hwabyung (HB: anger syndrome). Twins completed self-report questionnaires of the HB symptoms scale and the somatization scale via a telephone interview. The results of the general sex-limitation model showed that 43% (95% CI [36, 50]) of the total variance of somatization was attributable to additive genetic factors, with the remaining variance, 57% (95% CI [50, 64]), being due to individual-specific environmental influences, including measurement error. These estimates were not significantly different between the two sexes. The phenotypic correlation between HB and somatization was .53 (p < .001). The bivariate model-fitting analyses revealed that the genetic correlation between the two symptoms was .68 (95% CI [.59, .77]), while the individual-specific environmental correlation, including correlated measurement error, was .41 (95% CI [.34, .48]). Of the additive genetic factors of 43% that influence somatization, approximately half (20%) were associated with those related to HB, with the remainder being due to genes unique to somatization. A substantial part (48%) of individual environmental variance in somatization was unrelated to HB; only 9% of the environmental variance was shared with HB. Our findings suggest that HB and somatization have shared genetic etiology, but environmental factors that precipitate the development of HB and somatization may be largely independent from each other.

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Effects of Chorion Type on Genetic and Environmental Influences on Height, Weight, and Body Mass Index in South Korean Young Twins

Twin Research and Human Genetics ◽

10.1375/twin.11.1.63 ◽

2008 ◽

Vol 11 (1) ◽

pp. 63-69 ◽

Cited By ~ 13

Author(s):

Yoon-Mi Hur ◽

Jung-Sik Shin

Keyword(s):

Body Mass Index ◽

Maximum Likelihood ◽

Body Mass ◽

Statistical Significance ◽

Environmental Influences ◽

Model Fitting ◽

Twin Design ◽

South Korean ◽

Classical Twin Design ◽

Chorion Type

AbstractThe present study examined the effects of chorionicity of twins on variations of height, weight, and body mass index (BMI) during childhood in the classical twin design. Mothers of 81 pairs of monochorionic monozygotic (MCMZ), 47 pairs of dichorionic monozygotic (DCMZ), and 457 pairs of dizygotic (DZ) twins drawn from the South Korean Twin Registry reported their children's height and weight. Twins' age ranged from 1.9 to 8.7 yrs, with a mean of 4.0 yrs and SD of 1.7 yrs. We computed maximum likelihood twin correlations and performed model-fitting analyses. In correlational and model-fitting analyses, we treated age and sex as covariates to control their main effects. Maximum likelihood MCMZ, DCMZ, and DZ twin correlations were, respectively, .96, .92, and .74, for height, .88, .91, and .57 for weight, and .93, .92, and .61 for BMI. The pattern of these twin correlations suggested very modest chorion effects on body measures. Model-fitting analyses confirmed the observations from twin correlations. Whereas genetic and shared environmental influences were significant for all three body measures, chorion effects attained statistical significance only for height (4%), and those for weight and BMI were zero. These findings indicate that genetic and environmental estimates for height, weight, and BMI during childhood are biased little by the chorion type of MZ twins, supporting the validity of the equal prenatal environment assumption in the classical twin design.

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Correlated genetic and non-shared environmental influences account for the co-morbidity between female sexual dysfunctions

Psychological Medicine ◽

10.1017/s0033291708003206 ◽

2008 ◽

Vol 39 (1) ◽

pp. 115-127 ◽

Cited By ~ 18

Author(s):

K. Witting ◽

P. Santtila ◽

F. Rijsdijk ◽

M. Varjonen ◽

P. Jern ◽

...

Keyword(s):

Environmental Factors ◽

Sexual Function ◽

Genetic Factors ◽

Environmental Influences ◽

Model Fitting ◽

Sexual Dysfunctions ◽

Co Morbidity ◽

Genetic And Environmental Factors ◽

Correlated Factors ◽

Best Fit

BackgroundPrevious studies have shown moderate heritability for female orgasm. So far, however, no study has addressed the pattern of genetic and environmental influences on diverse sexual dysfunctions in women, nor how genetic and environmental factors contribute to the associations between them.MethodThe sample was drawn from the Genetics of Sex and Aggression (GSA) sample and consisted of 6446 female twins (aged 18–43 years) and 1994 female siblings (aged 18–49 years). The participants responded to the Female Sexual Function Index (FSFI), either by post or online.ResultsModel fitting analyses indicated that individual differences on all six subdomains of the FSFI (desire, arousal, lubrication, orgasm, satisfaction, and pain) were primarily due to non-shared (individual-specific) environmental influences. Genetic influences were modest but significant, whereas shared environmental influences were not significant. A correlated factors model including additive and non-additive genetic and non-shared environmental effects proved to have the best fit and suggested that both correlated additive and non-additive genetic factors and unique environmental factors underlie the co-occurrence of the sexual function problems.ConclusionsThe findings suggest that female sexual dysfunctions are separate entities with some shared aetiology. They also indicate that there is a genetic susceptibility for sexual dysfunctions. The unique experiences of each individual are, however, the main factors determining if, and which, dysfunction develops.

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Sex Differences in Genetic and Environmental Influences on Educational Attainment and Income

Twin Research and Human Genetics ◽

10.1017/thg.2014.68 ◽

2014 ◽

Vol 17 (6) ◽

pp. 516-525 ◽

Cited By ~ 5

Author(s):

Ragnhild E. Ørstavik ◽

Nikolai Czajkowski ◽

Espen Røysamb ◽

Gun Peggy Knudsen ◽

Kristian Tambs ◽

...

Keyword(s):

Gender Differences ◽

Sex Differences ◽

Environmental Factors ◽

Educational Attainment ◽

Educational Level ◽

Environmental Influences ◽

Phenotypic Correlation ◽

Qualitative And Quantitative ◽

Genetic And Environmental Factors ◽

The Relationship

In many Western countries, women now reach educational levels comparable to men, although their income remains considerably lower. For the past decades, it has become increasingly clear that these measures of socio-economic status are influenced by genetic as well as environmental factors. Less is known about the relationship between education and income, and sex differences. The aim of this study was to explore genetic and environmental factors influencing education and income in a large cohort of young Norwegian twins, with special emphasis on gender differences. National register data on educational level and income were obtained for 7,710 twins (aged 29–41 years). Bivariate Cholesky models were applied to estimate qualitative and quantitative gender differences in genetic and environmental influences, the relative contribution of genetic and environmental factors to the correlation between education and income, and genetic correlations within and between sexes and phenotypes. The phenotypic correlation between educational level and income was 0.34 (0.32–0.39) for men and 0.45 (0.43–0.48) for women. An ACE model with both qualitative and quantitative sex differences fitted the data best. The genetic correlation between men and women (rg) was 0.66 (0.22–1.00) for educational attainment and 0.38 (0.01–0.75) for income, and between the two phenotypes 0.31 (0.08–0.52) for men and 0.72 (0.64–0.85) for women. Our results imply that, in relatively egalitarian societies with state-supported access to higher education and political awareness of gender equality, genetic factors may play an important role in explaining sex differences in the relationship between education and income.

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