scholarly journals Twin Studies of Atopic Dermatitis: Interpretations and Applications in the Filaggrin Era

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Camilla Elmose ◽  
Simon Francis Thomsen
Keyword(s):  
Genetic Factors ◽  
Clinical Manifestations ◽  
Twin Studies ◽  
Population Based ◽  
Future Research ◽  
Atopic Diseases ◽  
Environmental Correlations ◽  
Disease Trait ◽  
Overall Ratio ◽  
The Relationship

Aim. The aim of this study was to conduct a systematic review of population-based twin studies of (a) the concordance and heritability of AD and (b) the relationship between AD and asthma and, furthermore, to reinterpret findings from previous twin studies in the light of the emerging knowledge about filaggrin and its role in the atopic march and provide suggestions for future research in this area. Methods. We identified all twin studies (published after 1970) that have calculated the concordance rate and/or the heritability of AD, or the genetic and environmental correlations between AD and asthma. Results. Reported concordance rates for AD ranged, respectively. From 0.15 to 0.86 for MZ and from 0.05 to 0.41 for DZ twins, with an overall ratio of MZ : DZ twins of approximately three. The heritability of AD was estimated to be approximately 75%, and the association between AD and asthma was around 85% explained by genetic pleiotropy. Conclusions. Genetic factors account for most of the variability in AD susceptibility and for the association between AD and asthma. Controversy remains as to whether the atopic diseases are causally related or whether they are diverse clinical manifestations of a common, underlying (genetic) disease trait. Future twin studies may help solve this enigma.

scholarly journals Twin studies for the investigation of the relationships between genetic factors and brain abnormalities in bipolar disorder

2016 ◽  
Vol 25 (6) ◽  
pp. 515-520 ◽  
Author(s):  
L. Squarcina ◽  
C. Fagnani ◽  
M. Bellani ◽  
C. A. Altamura ◽  
P. Brambilla
Keyword(s):  
Bipolar Disorder ◽  
Family Environment ◽  
Brain Structure ◽  
Genetic Factors ◽  
Genetic Research ◽  
Twin Studies ◽  
Neural Mechanisms ◽  
Shared Environment ◽  
High Heritability ◽  
The Relationship

The pathogenesis of bipolar disorder (BD) is to date not entirely clear. Classical genetic research showed that there is a contribution of genetic factors in BD, with high heritability. Twin studies, thanks to the fact that confounding factors as genetic background or family environment are shared, allow etiological inferences. In this work, we selected twin studies, which focus on the relationship between BD, genetic factors and brain structure, evaluated with magnetic resonance imaging. All the studies found differences in brain structure between BD patients and their co-twins, and also in respect to healthy controls. Genetic effects are predominant in white matter, except corpus callosum, while gray matter resulted more influenced by environment, or by the disease itself. All studies found no interactions between BD and shared environment between twins. Twin studies have been demonstrated to be useful in exploring BD pathogenesis and could be extremely effective at discriminating the neural mechanisms underlying BD.

Inflammatory bowel disease is associated with higher dementia risk: a nationwide longitudinal study

Gut ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Bing Zhang ◽  
Hohui E Wang ◽  
Ya-Mei Bai ◽  
Shih-Jen Tsai ◽  
Tung-Ping Su ◽  
...  
Keyword(s):  
Neurodegenerative Disorder ◽  
Disease Risk ◽  
Subsequent Development ◽  
Population Based ◽  
Future Research ◽  
Research Database ◽  
Dementia Risk ◽  
The Central Nervous System ◽  
Inflammatory Bowel ◽  
The Relationship

ObjectiveIncreasing evidence supports reciprocal communication between the enteric and the central nervous system in disease, termed the ‘gut–brain axis’. Recent findings suggest a connection between IBD and development of Parkinson’s disease. The role of IBD in dementia, another insidious neurodegenerative disorder, has not been explored.DesignUsing the Taiwanese National Health Insurance Research Database, we performed comparative analysis of 1742 patients with IBD ≥45 years old against 17 420 controls to assess dementia risk following IBD diagnosis. Controls were matched on bases of sex, access to healthcare, income and dementia-related comorbidities. All individuals were followed for dementia diagnosis for up to 16 years. Subanalyses included the relationship between sex, ulcerative colitis (UC) and Crohn’s disease (CD), and dementia risk.ResultsOverall incidence of dementia among patients with IBD was significantly elevated (5.5% vs 1.4% among controls). Patients with IBD were diagnosed with dementia at 76.24 years old on average, compared with 83.45 among controls. The HR of developing dementia among patients with IBD was 2.54 (95% CI 1.91 to 3.37). Among dementia types, the risk of developing Alzheimer’s dementia demonstrated the greatest increase. Dementia risk did not differ between sex differences nor UC versus CD.ConclusionThis population-based cohort study demonstrates significant association between IBD and subsequent development of dementia. Dementia was diagnosed at an earlier age among patients with IBD, and disease risk appeared to increase with IBD chronicity. These findings highlight the need for future research to elucidate the relationship between IBD and dementia.

Cause and effect in studies on unemployment, mental health and suicide: a meta-analytic and conceptual review

2013 ◽  
Vol 44 (5) ◽  
pp. 909-917 ◽  
Author(s):  
A. Milner ◽  
A. Page ◽  
A. D. LaMontagne
Keyword(s):  
Mental Health ◽  
Meta Analysis ◽  
Population Based ◽  
Future Research ◽  
Temporal Relationships ◽  
Causal Assumptions ◽  
Confounder Adjustment ◽  
Past Experiences ◽  
Study Designs ◽  
The Relationship

BackgroundThere are ongoing questions about whether unemployment has causal effects on suicide as this relationship may be confounded by past experiences of mental illness. The present review quantified the effects of adjustment for mental health on the relationship between unemployment and suicide. Findings were used to develop and interpret likely causal models of unemployment, mental health and suicide.MethodA random-effects meta-analysis was conducted on five population-based cohort studies where temporal relationships could be clearly ascertained.ResultsResults of the meta-analysis showed that unemployment was associated with a significantly higher relative risk (RR) of suicide before adjustment for prior mental health [RR 1.58, 95% confidence interval (CI) 1.33–1.83]. After controlling for mental health, the RR of suicide following unemployment was reduced by approximately 37% (RR 1.15, 95% CI 1.00–1.30). Greater exposure to unemployment was associated with higher RR of suicide, and the pooled RR was higher for males than for females.ConclusionsPlausible interpretations of likely pathways between unemployment and suicide are complex and difficult to validate given the poor delineation of associations over time and analytic rationale for confounder adjustment evident in the revised literature. Future research would be strengthened by explicit articulation of temporal relationships and causal assumptions. This would be complemented by longitudinal study designs suitable to assess potential confounders, mediators and effect modifiers influencing the relationship between unemployment and suicide.

Sleep and pain

2018 ◽  
Author(s):  
Nicole K. Y. Tang ◽  
Esther F. Afolalu ◽  
Fatanah Ramlee
Keyword(s):  
Public Health ◽  
Primary Care ◽  
Population Level ◽  
Population Based ◽  
Future Research ◽  
Long Term Conditions ◽  
Treatment Development ◽  
The Individual ◽  
The Relationship

Pain and sleeplessness are two of the commonest reasons for primary care appointments. The prevalence of each problem alone is high, and to add to the complexity, pain and insomnia frequently co-occur, with pain interrupting sleep and pain being further aggravated following a poor night’s sleep. Sleep and pain management are increasingly recognized as important to public health. In particular, insomnia and chronic pain are long-term conditions that actively contribute to morbidity, disability, economic burden to society, and suffering to the individual and immediate family. This chapter examines the interrelationship between the two at the population level. Specifically, evidence from population-based studies regarding the co-occurrence and temporal link of pain and sleep is reviewed, with moderators and mediators of the relationship highlighted. Possible directions for future research and treatment development are also outlined.

A twin study of genetic and environmental influences on tobacco initiation, regular tobacco use and nicotine dependence

2004 ◽  
Vol 34 (7) ◽  
pp. 1251-1261 ◽  
Author(s):  
HERMINE H. MAES ◽  
PATRICK F. SULLIVAN ◽  
CYNTHIA M. BULIK ◽  
MICHAEL C. NEALE ◽  
CAROL A. PRESCOTT ◽  
...  
Keyword(s):  
Nicotine Dependence ◽  
Tobacco Use ◽  
Structural Equation ◽  
Genetic Factors ◽  
Smoking Behavior ◽  
Twin Studies ◽  
Population Based ◽  
Equation Modeling ◽  
Opposite Sex ◽  
Tobacco Initiation

Background. Numerous twin studies have reported significant genetic contributions to the variability of tobacco initiation (TI), while fewer studies have shown similar results for the persistence of smoking behavior, or nicotine dependence (ND). As the development of ND requires regular tobacco use (RTU) which in turn requires TI, a conditional approach is necessary.Method. We used structural equation modeling of multi-step conditional processes to examine the relationship between genetic and environmental risk factors for TI, RTU and ND. The tobacco variables were assessed by personal interview in female, male and opposite-sex twin pairs from the population-based Virginia Twin Registry.Results. The results suggested that the liabilities to TI, RTU and ND were correlated. Over 80% of the variance in liability to TI and RTU were shared, and a smaller proportion was shared between RTU and ND. The heritabilities were estimated at 75%, 80% and 60% respectively for TI, RTU and ND. The variance specific to liability to RTU was entirely accounted for by additive genetic factors. Only a modest part of the heritability in liability of ND was due to genetic factors specific to ND. Shared environmental factors were not significant. No sex differences were found for the sources of variation or causal paths, but prevalences were significantly greater in males versus females.Conclusions. This study showed significant overlap in the contribution of genetic factors to individual differences in TI, RTU and ND. Furthermore, there was evidence for significant additional genetic factors specific to RTU and ND.

scholarly journals Exploring the relationship between pain and self-harm thoughts and behaviours in young people using network analysis

2021 ◽  
pp. 1-10
Author(s):  
Verena Hinze ◽  
Tamsin Ford ◽  
Robin Evans ◽  
Bergljot Gjelsvik ◽  
Catherine Crane
Keyword(s):  
Network Analysis ◽  
Young People ◽  
Stressful Life Events ◽  
Population Based ◽  
Family Dysfunction ◽  
Health Concern ◽  
Future Research ◽  
Parental Distress ◽  
Self Harm ◽  
The Relationship

Abstract Background Self-harm thoughts and behaviours (SHTBs) are a serious public health concern in young people. Emerging research suggests that pain may be an important correlate of SHTBs in young people. However, it remains unclear whether this association is driven by the shared association with other correlates of SHTBs. This study used network analysis to delineate the relationship between SHTBs, pain and other correlates of SHTBs in a population-based sample of young people. Methods We performed secondary analyses, using data from 7977 young people aged 5–16 years who participated in the British Child and Adolescent Mental Health Survey in 2004. We used χ2 tests and network analysis to examine the complex interplay between SHTBs, pain and other correlates of SHTBs, including psychiatric disorders, childhood trauma, stressful life events, parental distress, family dysfunction, peer problems and inhibitory control deficits. Results Pain was associated with a doubled risk of SHTBs, and likewise, SHTBs were associated with a doubled risk of pain. Furthermore, network analysis showed that although pain was significantly associated with all measured correlates of SHTBs, except family dysfunction, pain was most strongly associated with SHTBs, after accounting for these measured correlates. Conclusions To the best of our knowledge, this is the first study to utilise network analysis to provide novel insights into the complex relationship between SHTBs, pain and other known correlates of SHTBs in young people. Results suggest that pain is an independent correlate of SHTBs. Future research should aim to identify underlying mechanisms.

scholarly journals Contrasting multilevel relationships between behavior and body mass in blue tit nestlings

2020 ◽  
Vol 31 (3) ◽  
pp. 702-710 ◽  
Author(s):  
Barbara Class ◽  
Jon Brommer
Keyword(s):  
Body Mass ◽  
Future Research ◽  
Blue Tit ◽  
Environmental Correlations ◽  
Underlying Mechanisms ◽  
Opposing Effects ◽  
And Behavior ◽  
The Relationship ◽  
Genetic Integration ◽  
Different Levels

Abstract Repeatable behaviors (i.e., animal personality) are pervasive in the animal kingdom and various mechanisms have been proposed to explain their existence. Genetic and nongenetic mechanisms, which can be equally important, predict correlations between behavior and body mass on different levels (e.g., genetic and environmental) of variation. We investigated multilevel relationships between body mass measured on weeks 1, 2, and 3 and three behavioral responses to handling, measured on week 3, which form a behavioral syndrome in wild blue tit nestlings. Using 7 years of data and quantitative genetic models, we find that all behaviors and body mass on week 3 are heritable (h2 = 0.18–0.23) and genetically correlated, whereas earlier body masses are not heritable. We also find evidence for environmental correlations between body masses and behaviors. Interestingly, these environmental correlations have different signs for early and late body masses. Altogether, these findings indicate genetic integration between body mass and behavior and illustrate the impacts of early environmental factors and environmentally mediated growth trajectory on behaviors expressed later in life. This study, therefore, suggests that the relationship between personality and body mass in developing individuals is due to various underlying mechanisms, which can have opposing effects. Future research on the link between behavior and body mass would benefit from considering these multiple mechanisms simultaneously.

Head Circumference as a Measure of Cognitive Reserve

1996 ◽  
Vol 169 (1) ◽  
pp. 86-92 ◽  
Author(s):  
A. B. Graves ◽  
J. A. Mortimer ◽  
E. B. Larson ◽  
A. Wenzlow ◽  
J. D. Bowen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Head Circumference ◽  
Cognitive Abilities ◽  
Cognitive Reserve ◽  
Brain Size ◽  
Clinical Manifestations ◽  
Population Based ◽  
Japanese Americans ◽  
The Relationship

BackgroundRecent studies suggest that larger brain size may offer some protection against the clinical manifestations of Alzheimer's disease. However, this association has not been investigated in population-based studies.MethodThe relationship between head circumference, a measure of premorbid brain size, and score on the Cognitive Abilities Screening Instrument (CASI) was studied in a population of 1985 Japanese–Americans aged 65+ living in King County, Washington, USA.ResultsAfter adjusting for age, sex and education, head circumference was positively associated with CASI score (b=3.8, 95% CI: 2.2, 5.4; P=0.0000), but not with diagnosis of probable AD (odds ratio=0.87, 95% CI: 0.33, 1.87). When the data were stratified by AD status, no association was seen among controls (b=1.6, 95% CI: – 1.7, 5.1; P=0.4), whereas a strong effect was present among cases (b=35.3, 95% CI: 12.2, 58.4: P=0.006).ConclusionsThese results suggest that persons with AD with smaller head circumference either had the disease longer or progressed more rapidly than those with larger head circumference. Improvement in environmental factors in prenatal and early life that partially determine completed brain/head size may have consequences for the late-life expression of Alzheimer's disease in vulnerable individuals.

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

2015 ◽  
Vol 18 (3) ◽  
pp. 290-297 ◽  
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.

No Evidence of Genetic Mediation in the Association Between Birthweight and Academic Performance in 2,413 Danish Adolescent Twin Pairs

2009 ◽  
Vol 12 (6) ◽  
pp. 564-572 ◽  
Author(s):  
Inge Petersen ◽  
Vibeke Myrup Jensen ◽  
Matt McGue ◽  
Paul Bingley ◽  
Kaare Christensen
Keyword(s):  
Academic Performance ◽  
Genetic Factors ◽  
Large Population ◽  
Twin Studies ◽  
Positive Association ◽  
Population Based ◽  
Birth Cohorts ◽  
Individual Level ◽  
Shed Light ◽  
Danish Twin

AbstractEvidence of a positive association between birthweight and IQ has been established in several studies. Analyses of within twin pair differences in birthweight and IQ have been used to shed light on the basis of the association. The strength of this approach is the possibility of controlling for both unmeasured common childhood–environmental factors as well as genetic factors shared by the co-twins. Two twin studies suggest the existence of genetic mediation between birthweight and IQ, that is, common genetic factors influence both fetal growth and IQ in childhood, while two other twin studies find no evidence of such mediation. In the present study we use a large population-based national register study of 2,413 Danish twin-pairs from birth cohorts 1986–1990, of which we have zygosity information on 74%. We perform individual level as well as intra-pair analyses of birthweight and school achievements at age 16. For both sexes we observed a monotonic increase in academic performance with increasing percentiles of birthweight. However, we did not find that this association is due to genetic mediation.

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