Genetic and Environmental Factors in Alexithymia: A Population-Based Study of 8,785 Danish Twin Pairs

2007 ◽  
Vol 76 (6) ◽  
pp. 369-375 ◽  
Author(s):  
Michael Martini Jørgensen ◽  
Robert Zachariae ◽  
Axel Skytthe ◽  
Kirsten Kyvik
2001 ◽  
Vol 44 (2-3) ◽  
pp. 167-178 ◽  
Author(s):  
Marianne Juel Kjeldsen ◽  
Kirsten Ohm Kyvik ◽  
Kaare Christensen ◽  
Mogens Laue Friis

2005 ◽  
Vol 8 (2) ◽  
pp. 138-147 ◽  
Author(s):  
Marianne J. Kjeldsen ◽  
Linda A. Corey ◽  
Marit H. Solaas ◽  
Mogens L. Friis ◽  
Jennifer R. Harris ◽  
...  

AbstractThe purpose of the study was to describe a large sample of twins reporting a history of seizures, to characterize seizures in the three subpopulations, and to estimate the relative importance of genetic and environmental factors in seizure occurrence. Seizure history was determined by questionnaires completed by twins in population-based twin registries in the United States, Norway and Denmark. Concordance rates were calculated for all seizure categories within and across twin populations. Of 47,626 twin pairs evaluated, 6234 reported a history of seizures in one or both twins. Concordance rates were significantly higher for monozygotic (MZ) versus dizygotic (DZ) pairs for all seizure categories within and across populations. The results of this study involving the largest unselected, population-based sample of twins with seizures assembled to date confirm the importance of genetic factors in determining risk for epilepsy, febrile seizures, other seizures and staring spells. This sample is likely to provide an important resource for studying the genetics of epilepsy subtypes and febrile seizures.


2007 ◽  
Vol 13 (5) ◽  
pp. 673-675 ◽  
Author(s):  
A.H. Maghzi ◽  
M. Etemadifar ◽  
V. Shaygannejad ◽  
M. Saadatnia ◽  
M. Salehi ◽  
...  

Conjugal multiple sclerosis (MS) is a rare form of MS in which both spouses are affected, and at least one is affected after marriage. Among 1606 definite MS patients, 1076 were in marital relationship, among whom we identified six conjugal pairs, giving the conjugal rate of 0.5%. This rate is 12.5 times higher than the estimated risk of MS for the general population (0.04%). The observed conjugal rate suggests an increased risk of developing MS for MS patients' spouses, this could be due to transmission or, more likely, to the same environmental factors shared in adult life. Multiple Sclerosis 2007; 13: 673-675. http://msj.sagepub.com


2020 ◽  
Vol 14 (12) ◽  
pp. 1662-1671
Author(s):  
Kimberley W J van der Sloot ◽  
Rinse K Weersma ◽  
Behrooz Z Alizadeh ◽  
Gerard Dijkstra

Abstract Background and Aims Multiple genetic and environmental factors are involved in the aetiology of inflammatory bowel disease [IBD] including Crohn’s disease [CD] and ulcerative colitis [UC], but data on these exposome factors are difficult to identify. Several exposome factors such as smoking have been shown to be involved; as for other environmental factors, eg stress, results have been conflicting. Methods We performed a case-control study including 674 IBD patients of the 1000IBD cohort, frequency-matched based on sex and age with 1348 controls from the population-based Lifelines Cohort Study. Exposome data were obtained using the validated Groningen IBD Environmental Questionnaire [GIEQ], capturing exposome factors through different stages of life using 844 items, of which 454 were applicable to study the role of 93 exposome factors in disease aetiology. Logistic regression [LR] modelling with Bonferroni correction for multiple testing was applied to estimate the multivariable-adjusted effect of each exposome factor. Results For IBD, we identified four novel factors: stressful life events (CD odds ratio [OR] 2.61/UC OR 2.92), high perceived stress [2.29/2.67], alcohol use [0.40/0.43], and bronchial hyper-reactivity [3.04/2.36]. Four novel factors were associated with only CD: prenatal smoke exposure [1.89], having a bed partner [0.53], allergies [2.66], and cow’s milk hypersensitivity [5.87]; and two solely with UC: carpet flooring [0.57] and neuroticism [1.32]. Nine factors were replicated. Conclusions In this study we identified 10 novel, and replicated nine previously reported, exposome factors associated with IBD. Identifying these factors is important for both understanding disease aetiology and future prevention strategies to decrease the development of IBD in genetically susceptible persons.


2007 ◽  
Vol 37 (8) ◽  
pp. 1163-1172 ◽  
Author(s):  
AYMAN H. FANOUS ◽  
MICHAEL C. NEALE ◽  
STEVEN H. AGGEN ◽  
KENNETH S. KENDLER

ABSTRACTBackgroundThe relationship between personality and psychiatric illness is complex. It is not clear whether one directly causes the other.MethodIn a population-based sample of male twins (n=3030), we attempted to predict major depression (MD) from neuroticism (N) and extraversion (E) and vice versa, to evaluate the causal, scar, state, and prodromal hypotheses. In a longitudinal, structural equation twin model, we decomposed the covariation between N and MD into (a) genetic and environmental factors that are common to both traits, as well as specific to each one and (b) direct causal effects of N at time 1 on subsequent MD, as well as between MD and subsequent N.ResultsE was negatively correlated with lifetime and one-year prevalence of MD. N predicted the new onset of MD, and was predicted by both current and past MD. It did not predict the time to onset of MD. All of the covariation between N and MD was due to additive genetic and individual-specific environmental factors shared by both traits and a direct causal path between MD and N assessed later. No genetic factors were unique to either trait.ConclusionsIn men, N may be a vulnerability factor for MD but does not cause it directly. However, MD may have a direct causal effect on N. The genetic overlap between N and MD in men may be greater than in women.


1996 ◽  
Vol 97 (3) ◽  
pp. 319-323 ◽  
Author(s):  
A. M. Herskind ◽  
Matthew McGue ◽  
Niels V. Holm ◽  
Thorkild I. A. Sørensen ◽  
Bent Harvald ◽  
...  

2006 ◽  
Vol 9 (3) ◽  
pp. 431-437 ◽  
Author(s):  
Anu Raevuori ◽  
Anna Keski-Rahkonen ◽  
Richard J. Rose ◽  
Aila Rissanen ◽  
Jaakko Kaprio

AbstractIn the population-based FinnTwin16 study, proportions of genetic and environmental factors contributing to muscle dissatisfaction and muscle-enhancing substance use were assessed in 319 pairs of twin brothers: 141 monozygotic (MZ) and 178 dizygotic (DZ) pairs. In addition there were 86 twin individuals from pairs in which only one co-twin responded. Of all respondents, 30% experienced high muscle dissatisfaction. The corresponding proportion of muscle-enhancing substance use was 10%. The subjects were similar in age (23.8 years, 95% confidence interval [CI] 23.76–23.84), body mass index (23.7, 95% CI 23.5–23.9), and waist circumference (84.5 cm, 95% CI 83.7–85.2), independent of their muscle dissatisfaction or muscle-enhancing substance use status and independent of their zygosity. The MZ polychoric correlation for muscle dissatisfaction was .39 (95% CI .17–.58) and .27 for DZ pairs (95% CI .07–.46). The MZ tetrachoric correlation for muscle-enhancing substance use was .65 (95% CI .28–.87) and .56 for DZ pairs (95% CI .26–.78). The AE model, where additive genetic factors (A) accounted for 42% (95% CI .23–.59) and unique environmental factors (E) 58% (95% CI .41–.77) of the liability, provided the best fit for muscle dissatisfaction. The CE model, where common environmental factors (C) accounted for 60% (95% CI .37–.77) and unique environmental factors (E) 40% (95% CI .23–.63) of the liability, provided the best fit for muscle-enhancing substance use. Both genetic and unique (nonfamilial) environmental factors are involved in muscle dissatisfaction in the population. Nongenetic factors (both familial and non-familial) appear to best explain the use of muscle-enhancing substances.


2011 ◽  
Vol 41 (9) ◽  
pp. 1987-1995 ◽  
Author(s):  
N. Czajkowski ◽  
K. S. Kendler ◽  
K. Tambs ◽  
E. Røysamb ◽  
T. Reichborn-Kjennerud

BackgroundTo explore the genetic and environmental factors underlying the co-occurrence of lifetime diagnoses of DSM-IV phobia.MethodFemale twins (n=1430) from the population-based Norwegian Institute of Public Health Twin Panel were assessed at personal interview for DSM-IV lifetime specific phobia, social phobia and agoraphobia. Comorbidity between the phobias were assessed by odds ratios (ORs) and polychoric correlations and multivariate twin models were fitted in Mx.ResultsPhenotypic correlations of lifetime phobia diagnoses ranged from 0.55 (agoraphobia and social phobia, OR 10.95) to 0.06 (animal phobia and social phobia, OR 1.21). In the best fitting twin model, which did not include shared environmental factors, heritability estimates for the phobias ranged from 0.43 to 0.63. Comorbidity between the phobias was accounted for by two common liability factors. The first loaded principally on animal phobia and did not influence the complex phobias (agoraphobia and social phobia). The second liability factor strongly influenced the complex phobias, but also loaded weak to moderate on all the other phobias. Blood phobia was mainly influenced by a specific genetic factor, which accounted for 51% of the total and 81% of the genetic variance.ConclusionsPhobias are highly co-morbid and heritable. Our results suggest that the co-morbidity between phobias is best explained by two distinct liability factors rather than a single factor, as has been assumed in most previous multivariate twin analyses. One of these factors was specific to the simple phobias, while the other was more general. Blood phobia was mainly influenced by disorder specific genetic factors.


2009 ◽  
Vol 125 (8) ◽  
pp. 1953-1960 ◽  
Author(s):  
Farhad Pourfarzi ◽  
Anna Whelan ◽  
John Kaldor ◽  
Reza Malekzadeh

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