scholarly journals A Twin Study of Cigarette and Snus Initiation and Quantity of Use in Norwegian Adult Twins

2019 ◽  
Vol 22 (2) ◽  
pp. 108-113
Author(s):  
Kenneth S. Kendler ◽  
Steven H. Aggen ◽  
Nathan Gillespie ◽  
Nikolai Czajkowski ◽  
Eivind Ystrom ◽  
...  
Keyword(s):  
Public Health ◽  
Twin Study ◽  
Twin Studies ◽  
Self Report ◽  
Shared Environment ◽  
Cigarette Use ◽  
Environmental Correlations ◽  
Twin Models ◽  
Adult Twins

AbstractWhile snus has been the focus of increasing public health interest, twin studies have examined neither sources of individual variation for its use nor the sources of resemblance between snus and cigarette use. Twins from the Norwegian Institute of Public Health Panel were assessed by self-report questionnaire for the initiation of regular use and maximal quantity used for snus and cigarettes. Twin modeling was performed using OpenMx on data from 2767 twins including 856 complete pairs. Fitting univariate twin models produced similar results for cigarette initiation and quantity with estimates of additive genetic, shared environmental and unique environmental effects of approximately 77%, 0% and 23%, respectively. Estimates of snus initiation and quantity were, respectively, approximately 53%, 26% and 21%. Joint analyses suggested that the genetic, shared environmental and unique environmental correlations between cigarette and snus initiation and quantity were +.82, 0 and +.42, respectively. However, these results could not be statistically distinguished from a model which postulated that resemblance between cigarette initiation and quantity resulted from genetic and unique environmental correlations of +.47 and +.43. Compared with cigarette initiation and quantity of use in Norwegian twins, the role of genes was less prominent and shared environment more prominent for initiation and quantity of use of snus. Joint analyses of both tobacco phenotypes suggested, but did not confirm definitively, that genetic risk factors for cigarette and snus use were similar but not identical, while shared environmental factors existed that were specific to snus use.

scholarly journals The Value of Twins for Health and Medical Research: A Third of a Century of Progress

2020 ◽  
Vol 23 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Jeffrey M. Craig ◽  
Lucas Calais-Ferreira ◽  
Mark P. Umstad ◽  
Dedra Buchwald
Keyword(s):  
Genetic Variation ◽  
Medical Research ◽  
Twin Study ◽  
Environmental Influences ◽  
Twin Studies ◽  
Twin Research ◽  
Study Designs ◽  
Genetic Contributions

AbstractIn 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction between two categories of twin studies: those aimed at assessing genetic contributions to disease and those aimed at assessing environmental contributions while controlling for genetic variation. They concluded with a brief section on recently founded twin registries that had begun to provide unprecedented access to twins for medical research. Here we offer an overview of the twin research that, in our estimation, best represents the field has progress since 1984. We start by summarizing what we know about twinning. We then focus on the value of twin study designs to differentiate between genetic and environmental influences on health and on emerging applications of twins in multiple areas of medical research. We finish by describing how twin registries and networks are accelerating twin research worldwide.

scholarly journals Twin Research in the Post-Genomic Era: Dissecting the Pathophysiological Effects of Adversity and the Social Environment

2020 ◽  
Vol 21 (9) ◽  
pp. 3142 ◽  
Author(s):  
Jonathan D. Turner ◽  
Conchita D’Ambrosio ◽  
Claus Vögele ◽  
Martin Diewald
Keyword(s):  
Social Environment ◽  
Study Design ◽  
Twin Study ◽  
Controlled Trial ◽  
Twin Studies ◽  
Twin Design ◽  
The Social ◽  
The Individual ◽  
Randomised Controlled

The role of twins in research is evolving as we move further into the post-genomic era. With the re-definition of what a gene is, it is becoming clear that biological family members who share a specific genetic variant may well not have a similar risk for future disease. This has somewhat invalidated the prior rationale for twin studies. Case co-twin study designs, however, are slowly emerging as the ideal tool to identify both environmentally induced epigenetic marks and epigenetic disease-associated processes. Here, we propose that twin lives are not as identical as commonly assumed and that the case co-twin study design can be used to investigate the effects of the adult social environment. We present the elements in the (social) environment that are likely to affect the epigenome and measures in which twins may diverge. Using data from the German TwinLife registry, we confirm divergence in both the events that occur and the salience for the individual start as early as age 11. Case co-twin studies allow for the exploitation of these divergences, permitting the investigation of the role of not only the adult social environment, but also the salience of an event or environment for the individual, in determining lifelong health trajectories. In cases like social adversity where it is clearly not possible to perform a randomised-controlled trial, we propose that the case co-twin study design is the most rigorous manner with which to investigate epigenetic mechanisms encoding environmental exposure. The role of the case co-twin design will continue to evolve, as we argue that it will permit causal inference from observational data.

The etiologic role of genetic and environmental factors in criminal behavior as determined from full- and half-sibling pairs: an evaluation of the validity of the twin method

2014 ◽  
Vol 45 (9) ◽  
pp. 1873-1880 ◽  
Author(s):  
K. S. Kendler ◽  
S. L. Lönn ◽  
H. H. Maes ◽  
J. Sundquist ◽  
K. Sundquist
Keyword(s):  
Environmental Factors ◽  
Age Differences ◽  
Twin Study ◽  
Criminal Behavior ◽  
Shared Environment ◽  
Complex Disorders ◽  
Twin Method ◽  
Heritability Estimates ◽  
Genetic And Environmental Factors

BackgroundTwin studies have shown that criminal behavior (CB) is influenced by both genetic and shared environmental factors. Could these results be replicated using full-siblings and half-siblings?MethodIn 911 009 full-siblings reared together (FSRT), 41 872 half-siblings reared together (HSRT) and 52 590 half-siblings reared apart (HSRA), CB was assessed from the Swedish Crime Register. Modeling, including testing for age differences and rearing status, was performed using the OpenMx package.ResultsFive sibling models were fitted examining FSRT and HSRT 0–2 years different in age, and both FSRT and HSRT, and FSRT, HSRT and HSRA 0–10 years different in age with and without a specified shared environment indexing age differences. Heritability estimates for CB ranged from 33 to 55% in females and 39 to 56% in males, similar to those found in our prior twin study on the same population. Estimates for the shared environment varied from 1 to 14% in females and 10 to 23% in males, lower than those estimated in the twin study. The specified shared environment indexed by sibling age differences was significant in all models tested.ConclusionsHeritability estimates for CB from full- and half-siblings closely approximated those found from twins in the same population, validating the twin method. Shared environmental estimates were lower, suggesting the presence of shared environmental factors for CB specific to twins. When rearing status can be assessed, full- and half-siblings offer an additional method for assessing the role of genetic and environmental factors in complex disorders. However, age differences in siblings may need to be included in the models.

scholarly journals VALIDATION OF ZYGOSITY ASSESSMENT BY A SELF-REPORT QUESTIONNAIRE IN A SAMPLE OF ADULT SERBIAN TWINS

2019 ◽  
Vol 11 (4) ◽  
pp. 419-432 ◽  
Author(s):  
Petar Čolović ◽  
Bojan Branovački ◽  
Dragana Zgonjanin Bosić
Keyword(s):  
Cross Validation ◽  
Monozygotic Twins ◽  
Twin Studies ◽  
Self Report ◽  
Correct Identification ◽  
Dizygotic Twins ◽  
Zygosity Questionnaire ◽  
Small Set ◽  
Adult Twins ◽  
Physical Resemblance

Validation of a twin zygosity-estimating questionnaire, The Questionnaire of Twins’ Physical Resemblance, created by Oniszczenko et al. and used in European and Serbian twin studies, was carried out on a sample of 222 pairs (176 monozygotic, 46 dizygotic) of adult twins (average age 24.6). Four discriminant functions, use of different sets of indicators (zygosity questionnaire items), were applied in order to obtain the most correct and accurate estimates of zygosity. The first function was a predefined function used in European twin studies, the following two functions contained sets of 18 and 24 freely estimated indicators respectively, while the last one utilized the items with most consistent contributions to zygosity prediction. The analytic procedure included cross-validation, whereby the sample was randomly split into two subsamples, comprising 107 and 115 twin pairs. The results pointed to successful (over 90% correct) identification of monozygotic twins, and sizeably lower correctness in identifying dizygotic twins. Overall correctness of estimation exceeded 90%, with the small set of best-performing indicators. The results encourage questionnaire estimation of zygosity, and raise the issue of improving the classification procedure in dizygotic twins.

scholarly journals Genetics of Intermediate Phenotypes in Suicidal Behavor - Focus on Aggression

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
D. Rujescu ◽  
A. Hartmann ◽  
B. Schneider ◽  
A. Thalmeier ◽  
A. Schnabel ◽  
...  
Keyword(s):  
Suicidal Behavior ◽  
Large Scale ◽  
Twin Studies ◽  
Self Report ◽  
Impulsive Behavior ◽  
Genetic Studies ◽  
Intermediate Phenotypes ◽  
Suicide Completers ◽  
Validation Experiments

Family and twin studies point towards a partial heritability of suicidal behavior. We investigated the role of a comprehensive set of genes in this behavior. Their selection was driven by results from post mortem and genetic studies. 250 suicide attempters with various psychiatric disorders were compared with 2200 volunteers which were randomly selected from the general population. All subjects were administered standard psychiatric interviews including SCID as well as self-report questionnaires for anger-related traits. Especially, aggressive-impulsive behavior has been studied and associations with these intermediate phenotypes will be presented.Additionally a large-scale gene expression analysis using cDNA-microarrays to identify new candidate-genes for suicide was conducted. We found several genes to be differentially expressed in the orbitofrontal cortex of suicide completers. Cross-validation experiments using quantitative RT-PCR validated a few genes so far. These genes have been genotyped in our patients and controls and associations with suicidal behavior and intermediate phenotypes, like aggression and impulsivity will be presented.

scholarly journals The Genetic Architecture of Neuroticism in 3301 Dutch Adolescent Twins as a Function of Age and Sex: A Study From the Dutch Twin Register

2006 ◽  
Vol 9 (1) ◽  
pp. 24-29 ◽  
Author(s):  
David C. Rettew ◽  
Jacqueline M. Vink ◽  
Gonneke Willemsen ◽  
Alicia Doyle ◽  
James J. Hudziak ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Total Sample ◽  
Self Report ◽  
Shared Environment ◽  
Eysenck Personality Questionnaire ◽  
Present Sample ◽  
Adolescent Twins ◽  
Dutch Twin Register ◽  
Age And Sex

AbstractThe objective of this study was to estimate the magnitude of genetic and environmental influences to variation in adolescent neuroticism as a function of age and sex. Neuroticism was assessed using the Amsterdamse Biografische Vragenlijst (ABV): a self-report personality instrument similar in content to the Eysenck Personality Questionnaire. Genetic modeling procedures, including age as modifier, were fitted to the total sample of 3301 Dutch adolescent twins aged 12 to 17 years (mean age 15.5). Significant influences of additive genetic factors (.59, 95% confidence intervals [CI] .54–.63) and unshared environmental factors (.41, 95% CI .37–.45) were found. Our data did not support a role of shared environment. Results showed that different genes may influence variation in neuroticism between girls and boys. No interaction was found between the variance components and age. Results generally support prior findings in adults and young children that neuroticism is influenced principally by additive genetic and unique environmental factors. The magnitude of the genetic component appears higher in the present sample of adolescents than in most studies of adults. The present study suggests that, in adolescence, different genes are expressed in boys and girls.

Has the “Equal Environments” Assumption Been Tested in Twin Studies?

Twin Research ◽  
2003 ◽  
Vol 6 (6) ◽  
pp. 486-489 ◽  
Author(s):  
Lindon Eaves ◽  
Debra Foley ◽  
Judy Silberg
Keyword(s):  
Genetic Factors ◽  
Twin Studies ◽  
Shared Environment ◽  
Environment Interaction ◽  
Genotype X Environment ◽  
Dizygotic Twins ◽  
Equal Environments Assumption ◽  
Twin Method ◽  
Equal Environments

AbstractArecurring criticism of the twin method for quantifying genetic and environmental components of human differences is the necessity of the so-called “equal environments assumption” (EEA) (i.e., that monozygotic and dizygotic twins experience equally correlated environments). It has been proposed to test the EEA by stratifying twin correlations by indices of the amount of shared environment. However, relevant environments may also be influenced by genetic differences. We present a model for the role of genetic factors in niche selection by twins that may account for variation in indices of the shared twin environment (e.g., contact between members of twin pairs). Simulations reveal that stratification of twin correlations by amount of contact can yield spurious evidence of large shared environmental effects in some strata and even give false indications of genotype x environment interaction. The stratification approach to testing the equal environments assumption may be misleading and the results of such tests may actually be consistent with a simpler theory of the role of genetic factors in niche selection.

The Relationship Between Personality and Self-Report Abilities

2011 ◽  
Vol 32 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Julie Aitken Schermer ◽  
Andrew M. Johnson ◽  
Philip A. Vernon ◽  
Kerry L. Jang
Keyword(s):  
Interpersonal Relationships ◽  
Self Report ◽  
Personality Factors ◽  
Personality Factor ◽  
Factor Scores ◽  
Environmental Correlations ◽  
Ability Factor ◽  
Genetic Level ◽  
The Relationship ◽  
Common Environmental Factor

The relationship between self-report abilities and personality was examined at both the phenotypic (zero-order) level as well as at the genetic and environmental levels. Twins and siblings (N = 516) completed self-report ability and personality questionnaires. A factor analysis of the ability questions revealed 10 factors, including politics, interpersonal relationships, practical tasks, intellectual pursuits, academic skills, entrepreneur/business, domestic skills, vocal abilities, and creativity. Five personality factors were examined, including extraversion, conscientiousness, dependence, aggression, and openness. At the phenotypic level, the correlations between the ability factor scores and personality factor scores ranged from 0 to .60 (between political abilities and extraversion). The relationship between the two areas at the genetic level was found to range between –.01 and .60; the environmental correlations ranged from –.01 to .48. The results suggest that some of the self-report ability scores are related to self-report personality, and that some of these observed relationships may have a common genetic basis while others are from a common environmental factor.

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