A twin study of self-regulatory eating in early childhood: estimates of genetic and environmental influence, and measurement considerations

Glutathione and cysteine are major antioxidants in blood that are associated with health and longevity. To ensure their measurement, careful attention to avoid auto-oxidation is necessary to stabilize the samples. Since no report of these compounds has been reported in children, our goal was to determine their levels of reduced and oxidized glutathione (GSH and GSSG) and cysteine (Cys and CSSC), To this end, 140 healthy children, ages 2 to 9 years from the Louisville Twin Study were studied. Blood samples were collected and analyzed for GSH, GSSG, Cys, and CSSC by our HPLC dual electrochemical method. The results showed that GSH and total GSH (GSH + GSSG) levels for monozygotic (MZ) twins were significantly higher (P < 0.001) than levels for dizygotic (DZ) twins. However, the opposite occurred for Cys and total Cys (Cys + CSSC) in that the levels were significantly higher for DZ twins than for MZ twins. (P < 0.005-0.013). In spite of this marked difference in zygosity, the withinpair correlations for twin pairs used for estimating heritability suggested that there was a major environmental influence for total GSH and total Cys. Finally. GSH levels were significantly lower for young (2–9 years) children than adults (P < 0.001).

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The development of inhibitory control in early childhood: A twin study from 2–3 years.

Developmental Psychology ◽

10.1037/dev0000090 ◽

2016 ◽

Vol 52 (3) ◽

pp. 391-399 ◽

Cited By ~ 17

Author(s):

Jeffrey R. Gagne ◽

Kimberly J. Saudino

Keyword(s):

Early Childhood ◽

Inhibitory Control ◽

Twin Study

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Familial Resemblance in Religiousness in a Secular Society: A Twin Study

Twin Research and Human Genetics ◽

10.1017/thg.2013.3 ◽

2013 ◽

Vol 16 (2) ◽

pp. 544-553 ◽

Cited By ~ 8

Author(s):

Dorte Hvidtjørn ◽

Inge Petersen ◽

Jacob Hjelmborg ◽

Axel Skytthe ◽

Kaare Christensen ◽

...

Keyword(s):

Family Environment ◽

Twin Study ◽

Church Attendance ◽

Environmental Influence ◽

Population Based ◽

Web Based ◽

Psychological Traits ◽

Social Forms ◽

Secular Society ◽

Using Data

It is well known that human behavior and individual psychological traits are moderately to substantially heritable. Over the past decade, an increasing number of studies have explored the genetic and environmental influence on religiousness. These studies originate predominantly from countries generally considered more religious than the very secular northern European countries. Comparisons of the results are complicated by diverse definitions of religiousness, but several studies indicate that the influence of the family environment is most predominant in early life, whereas genetic influences increase with age. We performed a population-based twin study of religiousness in a secular society using data from a Web-based survey sent to 6,707 Danish twins born 1970–1989, who were identified in the Danish Twin Registry. We applied Fishman's three conceptual dimensions of religiousness: cognition, practice, and importance. In all polygenic models and biometric analyses, we controlled for gender and age. The study sample comprised 2,237 same sex twins, a response rate of 45%. We found high correlations within both monozygotic and dizygotic twin pairs in most items of religiousness, indicating a large influence from shared environmental factors. Personal religiousness such as praying to God, believing in God, and finding strength and comfort in religion were more influenced by genetic factors than were social forms of religiousness such as church attendance. We found a small tendency for increasing genetic influence with increasing age for some religious items, but not for all.

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Effect of genetic and environmental influences on hepatic steatosis: A classical twin study based on computed tomography

Imaging ◽

10.1556/1647.2020.00006 ◽

2020 ◽

Vol 12 (1) ◽

pp. 15-20

Author(s):

György Jermendy ◽

Márton Kolossváry ◽

Ibolya Dudás ◽

Ádám L. Jermendy ◽

Alexisz Panajotu ◽

...

Keyword(s):

Computed Tomography ◽

Environmental Factors ◽

Hepatic Steatosis ◽

Lipid Accumulation ◽

Twin Study ◽

Structural Equation ◽

Environmental Influence ◽

Environmental Influences ◽

Hepatic Lipid ◽

Hepatic Lipid Accumulation

AbstractBackground and aimsNon-alcoholic fatty liver disease (NAFLD) increases cardiovascular morbidity and mortality, and carries poor long-term hepatic prognosis. Data about the role of genetic and environmental factors in the hepatic lipid accumulation are limited. The aim of the study was to evaluate the genetic and environmental impact on the hepatic lipid accumulation within a cohort of adult twin pairs.Patients and methodsWe investigated 182 twin subjects [monozygotic (MZ, n = 114) and dizygotic (DZ, n = 68) same-gender twins (age 56.0 ± 9.6 years; BMI 27.5 ± 5.0 kg/m2; females 65.9%)] who underwent computed tomography (CT) with a 256-slice scanner. Using non-enhanced CT-images, we calculated the average value of hepatic attenuation [expressed in Hounsfield unit (HU)] suggesting hepatic lipid content. Crude data were adjusted to age, sex, BMI and HbA1c values. Intra-pair correlations were established, and structural equation models were used for quantifying the contribution of additive genetic (A), common environmental (C) and unique environmental (E) components to the investigated phenotype.ResultsThe study cohort represented a moderately overweight, middle-aged Caucasian population. There was no significant difference between MZ and DZ twin subjects regarding hepatic CT-attenuation (57.9 ± 12.6 HU and 59.3 ± 11.7 HU, respectively; p = 0.747). Age, sex, BMI and HbA1c adjusted co-twin correlations between the siblings showed that MZ twins have stronger correlations of HU values than DZ twins (rMZ = 0.592, p < 0.001; rDZ = 0.047, p = 0.690, respectively). Using the structural equation model, a moderate additive genetic dependence (A: 38%, 95% CI 15–58%) and a greater unique environmental influence (E: 62%, 95% CI 42–85%) was found. Common environmental influence was not identified (C: 0%).ConclusionThe results of our classical CT-based twin study revealed moderate genetic and greater environmental influences on the phenotypic appearance of hepatic steatosis, commonly referred to as NAFLD. Favorable changes of modifiable environmental factors are of great importance in preventing or treating NAFLD.

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A longitudinal twin study of physical aggression during early childhood: evidence for a developmentally dynamic genome

Psychological Medicine ◽

10.1017/s0033291713003218 ◽

2014 ◽

Vol 44 (12) ◽

pp. 2617-2627 ◽

Cited By ~ 34

Author(s):

E. Lacourse ◽

M. Boivin ◽

M. Brendgen ◽

A. Petitclerc ◽

A. Girard ◽

...

Keyword(s):

Growth Rate ◽

Early Childhood ◽

Physical Aggression ◽

Twin Study ◽

Genetic Factors ◽

Latent Growth Curve ◽

Growth Curve Model ◽

Latent Growth ◽

Latent Growth Curve Model ◽

Curve Model

BackgroundPhysical aggression (PA) tends to have its onset in infancy and to increase rapidly in frequency. Very little is known about the genetic and environmental etiology of PA development during early childhood. We investigated the temporal pattern of genetic and environmental etiology of PA during this crucial developmental period.MethodParticipants were 667 twin pairs, including 254 monozygotic and 413 dizygotic pairs, from the ongoing longitudinal Quebec Newborn Twin Study. Maternal reports of PA were obtained from three waves of data at 20, 32 and 50 months. These reports were analysed using a biometric Cholesky decomposition and linear latent growth curve model.ResultsThe best-fitting Cholesky model revealed developmentally dynamic effects, mostly genetic attenuation and innovation. The contribution of genetic factors at 20 months substantially decreased over time, while new genetic effects appeared later on. The linear latent growth curve model revealed a significant moderate increase in PA from 20 to 50 months. Two separate sets of uncorrelated genetic factors accounted for the variation in initial level and growth rate. Non-shared and shared environments had no effect on the stability, initial status and growth rate in PA.ConclusionsGenetic factors underlie PA frequency and stability during early childhood; they are also responsible for initial status and growth rate in PA. The contribution of shared environment is modest, and perhaps limited, as it appears only at 50 months. Future research should investigate the complex nature of these dynamic genetic factors through genetic–environment correlation (rGE) and interaction (G × E) analyses.

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Risk Factors Influencing Smoking Behavior: A Turkish Twin Study

Twin Research and Human Genetics ◽

10.1017/thg.2014.43 ◽

2014 ◽

Vol 17 (6) ◽

pp. 563-573 ◽

Cited By ~ 5

Author(s):

Sevgi Yurt Öncel ◽

Danielle M. Dick ◽

Hermine H. Maes ◽

Fazil Alıev

Keyword(s):

Environmental Factors ◽

Nicotine Dependence ◽

Twin Study ◽

Genetic Factors ◽

Structural Equation Models ◽

Environmental Influence ◽

Smoking Behavior ◽

Smoking Initiation ◽

Smoking History ◽

Shared Environmental Influence

Aim: In this study, we introduce the first twin study in Turkey, focusing on smoking behavior, and laying the foundation to register all twins born in Turkey for research purposes. Using Turkish twins will contribute to our understanding of health problems in the context of cultural differences. Materials and methods: We assessed 309 twin pairs (339 males and 279 females) aged between 15 and 45 years living in the Kırıkkale and Ankara regions of Turkey, and administered a health and lifestyle interview that included questions about smoking status and smoking history. We analyzed the data using descriptive statistics, t-tests, chi-square tests, and bivariate and multivariate clustered logistic regression. In addition, we fit bivariate Structural Equation Models (SEM) to determine contributions of latent genetic and environmental factors to smoking outcomes in this sample. Results: One hundred seventy-eight participants (28.8%) were identified as smokers, smoking every day for a month or longer, of whom 79.2% were males and 20.8% were females. Mean values for number of cigarettes per day and the Fagerstrom Test of Nicotine Dependence (FTND; Fagerstrom, 1978) score were higher in males than in females, and age of onset was earlier in males. There was a significant positive correlation between the FTND score and number of cigarettes smoked per day, and a significant negative correlation between both variables and age at onset of smoking. Our study showed that gender, presence of a smoking twin in the family, age, alcohol use, marital status, daily sports activities, and feeling moody all played a significant role in smoking behavior among twins. The twin analysis suggested that 79.5% of the liability to FTND was influenced by genetic factors and 20.5% by unique environment, while familial resemblance for smoking initiation was best explained by common environmental factors. Conclusions: Marked differences in the prevalence of smoking behavior in men versus women were observed for the Turkish population. Genetic analyses showed that common environmental factors primarily contributed to smoking initiation, while genetic factors explained a greater proportion of variance in liability to nicotine dependence. Our study shows higher heritability estimate of the FTND scores and higher shared environmental influence on smoking initiation for both males and females than reported in previous studies.

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Heritability of Thirty Cephalometric Parameters on Monozygotic and Dizygotic Twins: Twin Study Method

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-1318 ◽

2013 ◽

Vol 14 (2) ◽

pp. 304-311 ◽

Cited By ~ 2

Author(s):

T Praveen Kumar Reddy ◽

B Sunil Kumar ◽

Gojja Sreedevi ◽

Baratam Srinivas ◽

CMS Krishna Prasad ◽

...

Keyword(s):

Genetic Control ◽

Treatment Planning ◽

Growth Pattern ◽

Twin Study ◽

Orthodontic Treatment ◽

Environmental Influence ◽

Facial Growth ◽

Dizygotic Twins ◽

Genes And Environment ◽

Genetic Mechanisms

ABSTRACT Genetic mechanisms are already predominant during embryonic craniofacial morphogenesis, but environment is also thought to influence dentofacial morphology postnatally, particularly during facial growth. A better understanding of the relative effects of genes and environment on dentofacial and occlusal parameters should improve our knowledge on the etiology of orthodontic disorders and therefore also on the possibilities and limitations of the orthodontic treatment and treatment planning. The aim of the present study is to explore the genetic and environmental influence on craniofacial dimensions in a group of 19 pairs of twins using the twin study method. The twin study carried out here clearly indicates that craniofacial matrix is under substantial genetic control and the redirection of a basic growth pattern may be modified only within biological limits which are harmonious for the patient. How to cite this article Sreedevi G, Srinivas B, Reddy TPK, Prasad CMSK, Kumar BS, Satish R. Heritability of Thirty Cephalometric Parameters on Monozygotic and Dizygotic Twins: Twin Study Method. J Contemp Dent Pract 2013; 14(2):304-311.

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