scholarly journals Lifespans of Twins: Does Zygosity Matter?

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 166 ◽  
Author(s):  
Jacob Hjelmborg ◽  
Pia Larsen ◽  
Jaakko Kaprio ◽  
Matt McGue ◽  
Thomas Scheike ◽  
...  
Keyword(s):  
Population Based ◽  
Dizygotic Twin ◽  
Vital Status ◽  
Age Cohorts ◽  
Mortality Process ◽  
Dizygotic Twins ◽  
Twin Registry ◽  
The Difference ◽  
Lifespan Distribution ◽  
Danish Twin

Studies with twins provide fundamental insights to lifespans of humans. We aim to clarify if monozygotic and dizygotic twin individuals differ in lifespan, that is, if zygosity matters. We investigate whether a possible difference in mortality after infancy between zygosities is stable in different age cohorts, and whether the difference remains when twins with unknown zygosity are taken into account. Further, we compare the distribution of long-livers, that is, the upper-tail of the lifespan distribution, between monozygotic and same-sex dizygotic twin individuals. The Danish Twin Registry provides a nationwide cohort of 109,303 twins born during 1870 to 1990 with valid vital status. Standard survival analysis is used to compare mortality in monozygotic and dizygotic twin individuals and twin individuals with unknown zygosity. The mortality of monozygotic and dizygotic twin individuals differs slightly after taking into consideration effects of birth- and age-cohorts, gender differences, and that twins are paired. However, no substantial nor systematic differences remain when taking twins with unknown zygosity into account. Further, the distribution of long-livers is very similar by zygosity, suggesting the same mortality process. The population-based and oldest twin cohort ever studied suggests that monozygotic and dizygotic twins have similar lifespans.

Myeloproliferative Neoplasms in Danish Twins

2018 ◽  
Vol 139 (3) ◽  
pp. 195-198 ◽  
Author(s):  
Michael Asger  Andersen ◽  
Ole Weis Bjerrum ◽  
Ajenthen Ranjan ◽  
Vibe Skov ◽  
Torben A. Kruse ◽  
...  
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Case Reports ◽  
Monozygotic Twin ◽  
Dizygotic Twin ◽  
National Patient Registry ◽  
Twin Registry ◽  
Danish National Patient Registry ◽  
National Patient ◽  
Danish Twin

Objective: Myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases characterized by clonal hyperproliferation of immature and mature cells of the myeloid lineage. Genetic differences have been proposed to play a role in the development of MPNs. Monozygotic twin pairs with MPNs have been reported in a few case reports, but the MPN concordance pattern in twins remains unknown. Method: All twin pairs born in the period 1900–2010 were identified in the nationwide Danish Twin Registry. Only pairs with both twins alive on January 1, 1977, and those born thereafter were included to allow identification in the Danish National Patient Registry. Results: A total of 158 twin pairs were registered with an MPN diagnosis: 36 monozygotic, 104 dizygotic, and 18 pairs with unknown zygosity. MPNs were diagnosed in both twins in 4 pairs. The probandwise concordance rates for monozygotic twin pairs were higher than for dizygotic twin pairs (15 vs. 0%; p = 0.016). Conclusion: An estimated concordance rate of 15% (95% CI 0.059–0.31) is modest, but given the rarity of MPNs this finding is clinically relevant and provides further support for the role of genetic predisposition in the development of MPNs.

HLA Haplotypes in Dizygotic Twin Pairs: Are Dizygotic Twins More Similar Than Sibs?

Twin Research ◽  
2002 ◽  
Vol 5 (4) ◽  
pp. 287-288 ◽  
Author(s):  
Ingrid Louise Titlestad ◽  
Kirsten Ohm Kyvik ◽  
Tom Kristensen ◽  
Søren Lillevang
Keyword(s):  
Dna Typing ◽  
Polymorphic Markers ◽  
Dizygotic Twin ◽  
Haplotype Sharing ◽  
Chi Square ◽  
Twin Registry ◽  
Hla Type ◽  
Chi Square Test ◽  
Hla Haplotypes ◽  
Danish Twin

AbstractIt has been suggested that dizygotic twin pairs share two HLA haplotypes more often than ordinary siblings and thus might be genetically more alike. We tested this hypothesis in dizygotic twin pairs from the Danish Twin Registry. A total of 114 (60 female and 54 male) same-sexed healthy twin pairs aged 18–45 years participated. Dizygosity was established by means of DNA sequencing of nine polymorphic markers. HLA-A, B and Cw specificities were typed with serology, and if data were inconclusive, with DNA typing. If twin partners had the same HLA-types, they were assumed to share two haplotypes. If they had 1 HLA A, B and C antigen group in common they were assumed to share one haplotype and if they had no HLA types in common they were assumed to share zero haplotypes. Since HLA-types from parents were unavailable we could not test for identity-by-descent and thus had a risk of overestimating the number of twins sharing two haplotypes. A Chi-square test was used to compare observed numbers in each haplotype sharing group with the expected numbers. Twenty-nine (expected 28.5) twin pairs had two HLA-types in common, 52 (expected 57) had one HLA-type in common and 33 (expected 28.5) had zero HLA-types in common, p = 0.56. Our data show that DZ twins are not more similar than sibs from different pregnancies in general.

Greater occurrence of schizophrenia in dizygotic but not monozygotic twins

1999 ◽  
Vol 175 (5) ◽  
pp. 407-409 ◽  
Author(s):  
Ulla Kläning
Keyword(s):  
General Population ◽  
Record Linkage ◽  
Monozygotic Twins ◽  
Young Cohort ◽  
Case Register ◽  
Dizygotic Twins ◽  
The Difference ◽  
Direction Opposite ◽  
First Admission ◽  
Danish Twin

BackgroundA previous study demonstrated a higher rate of first hospitalisation for schizophrenia in twins than in singletons.AimsTo compare the schizophrenia rates in monozygotic twins, dizygotic twins and the general population.MethodThrough record linkage between the Young Cohort of the Danish Twin Register and the Danish Psychiatric Case Register, the rate of schizophrenia in’ monozygotic and dizygotic twins and the rate in the general population were compared.ResultsThe rate of first admission to hospital for schizophrenia in dizygotic twins was 40% greater than that in the general population. The rate in monozygotic twins was not increased. The difference between the rates in mono- and dizygotic twins was statistically significant (P < 0.001)ConclusionsThis result is surprising and is in the direction opposite to that expected, suggesting new possibilities in the study of risk factors.

Prevalence of a History of Testicular Cancer in a Cohort of Elderly Twins

1995 ◽  
Vol 44 (3-4) ◽  
pp. 189-192 ◽  
Author(s):  
M. M. Braun ◽  
N. E. Caporaso ◽  
W. F. Page ◽  
R. N. Hoover
Keyword(s):  
Testicular Cancer ◽  
Research Council ◽  
Monozygotic Twins ◽  
National Research Council ◽  
Dizygotic Twin ◽  
Cancer Risk Factors ◽  
Dizygotic Twins ◽  
Twin Registry ◽  
History Of

AbstractPrior studies have suggested that the risk of testicular cancer among dizygotic twins may exceed that among monozygotic twins or the general population. Cryptorchidism is associated with testicular cancer and twinship, and therefore might potentially explain the findings of the prior studies. In 1993-1994, when they were 66 to 77 years of age, 14,326 twin individuals in the National Academy of Sciencies-National Research Council Twin Registry were interviewed by telephone. A history of testicular cancer was reported by 5 (0.08%) of 5951 monozygotic twins and 11 (0.16%) of 6992 dizygotic twins. Follow-up interviews concerning testicular cancer risk factors and treatment were able to be administered to 4 of the monozygotic and 9 of the dizygotic twins reporting testicular cancer. A history of cryptorchidism was reported in the follow-up interview by only one dizygotic twin. Our data agree with the results of prior studies reporting a more frequent occurrence of testicular cancer among dizygotic than monozygotic twins. Although somewhat limited by small numbers, our study also suggests that the findings of increased testicular cancer in dizygotic twins are not explained simply by increased occurrence of cryptorchidism in twins.

Concordance for multiple sclerosis in Danish twins: an update of a nationwide study

2005 ◽  
Vol 11 (5) ◽  
pp. 504-510 ◽  
Author(s):  
T Hansen ◽  
A Skytthe ◽  
E Stenager ◽  
H C Petersen ◽  
H Brønnum-Hansen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Genetic Factors ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
Population Based ◽  
Data Sets ◽  
Dizygotic Twin ◽  
Population Based Study ◽  
Nationwide Study ◽  
Dizygotic Twins

The occurrence of multiple sclerosis (MS) in twins has not previously been studied in complete nationwide data sets. The existence of almost complete MS and twin registries in Denmark ensures that essentially unbiased samples of MS cases among twins can be obtained. In this population-based study, virtually all Danish MS cases among twins born before 1983 with onset of MS after 1948 and diagnosis before 1 January 1997 were identified. Of 13 286 MS cases, 178 were twins and, of these 164 twin pairs were discordant and seven were concordant. We found significantly higher proband-wise concordance among monozygotic twins than dizygotic twins, with estimated proband-wise concordances of 24% (95% confidence interval (CI): 5-39%) for monozygotic and 3% (95% CI: 0-8%) for dizygotic twins. Thus, a monozygotic twin whose co-twin has MS has a 24% risk of developing the disease, while the corresponding risk for a dizygotic twin is only 3%. Our results largely confirm previously published concordance estimates and indicate that genetic factors are of importance in susceptibility to MS.

Assessment of Dental Arch Parameters in Turkish Twins

2021 ◽  
Vol 45 (5) ◽  
pp. 359-370
Author(s):  
Sinem Birant ◽  
Mine Koruyucu ◽  
Yelda Kasimoglu ◽  
Mert Veznikli ◽  
Figen Seymen
Keyword(s):  
Monozygotic Twin ◽  
Wilcoxon Test ◽  
Dental Arch ◽  
Posterior Arch ◽  
Dizygotic Twin ◽  
Sibling Pairs ◽  
Arch Width ◽  
Dizygotic Twins ◽  
The Difference ◽  
Maxilla And Mandible

Background: The aim of this study is to investigate the relative contributions of genetic and environmental factors to variations in dental dimensions in a sample of Turkish twins, and to estimate heritability using dental casts. Study design: The study samples were selected from the twin children between 3–15 years old who referred for their first dental examination. Fifty nine monozygotic and one hundred and forty three dizygotic twin pairs were examined in the study. The alginate impression material used to create the plaster model of maxilla and mandible. Anterior arch width, posterior arch width, arch length and arch circumference were measured on models prepared from measurements taken for both maxilla and mandible with digital caliper. The similarities and differences of the measurements were compared between pairs of twins and zygocytes. Morever, the effects of bad oral habits, bruxism, a result of psychosocial factors on measurements were examined. Statistical analysis was performed using Paired T Test, Wilcoxon Test and Mann Whitney U test. Results: A total of 404 dental models of 118 (29.2%) monozygotic and 286 (70.8%) dizygotic twins were evaluated. There was no statistical difference between sibling pairs in both monozygotic and dizygotic twins. The measurement similarity between twin siblings differed according to zygosity in all measurements (p&lt;0.05). It has been observed that the finger sucking and mouth breathing affect the dental arch measurements (p&lt;0.05). Conclusion: These results indicate that the differences in dental arch dimensions between monozygotic twin pairs are less than the difference between dizygotic twin pairs.

The Cuban Twin Registry: Initial Findings and Perspectives

2012 ◽  
Vol 16 (1) ◽  
pp. 98-103 ◽  
Author(s):  
Beatriz Marcheco-Teruel ◽  
Marcia Cobas-Ruiz ◽  
Niviola Cabrera-Cruz ◽  
Araceli Lantigua-Cruz ◽  
Elsa García-Castillo ◽  
...  
Keyword(s):  
Population Based ◽  
Multiple Births ◽  
High Morbidity ◽  
Future Directions ◽  
The Past ◽  
Dizygotic Twins ◽  
Twin Registry ◽  
Research Findings ◽  
Extensive Information ◽  
Cuban Population

The Cuban Twin Registry is a nation-wide, prospective, population-based twin registry comprising all zygosity types and ages. It was initiated in 2004 to study genetic and environmental contributions to complex diseases with high morbidity and mortality in the Cuban population. The database contains extensive information from 55,400 twin pairs enrolled in the period 2004–2006. Additionally, 2,600 new multiple births have been included from 2007 to date. In the past 4 years, more than 130 studies have been carried out using the registry with a classical genetic epidemiological approach in which concordance rates for monozygotic and dizygotic twins and heritability of various disease traits were estimated. This article summarizes the history, registry's methodology, recent research findings, and future directions of work.

scholarly journals A new customised placental weight standard redefines the relationship between maternal obesity and extremes of placental size and is more closely associated with pregnancy complications than an existing population standard

2019 ◽  
Vol 11 (4) ◽  
pp. 350-359
Author(s):  
Jacqueline M. Wallace ◽  
Joeleita P. Agard ◽  
Graham W. Horgan
Keyword(s):  
Pregnancy Complications ◽  
Maternal Obesity ◽  
Population Based ◽  
Multiple Regression Model ◽  
Placental Weight ◽  
Morbidly Obese ◽  
Obese Women ◽  
Entire Cohort ◽  
Multiparous Women ◽  
The Difference

AbstractPlacental weight is a valuable indicator of its function, predicting both pregnancy outcome and lifelong health. Population-based centile charts of weight-for-gestational-age and parity are useful for identifying extremes of placental weight but fail to consider maternal size. To address this deficit, a multiple regression model was fitted to derive coefficients for predicting normal placental weight using records from healthy pregnancies of nulliparous/multiparous women of differing height and weight (n = 107,170 deliveries, 37–43 weeks gestation). The difference between actual and predicted placental weight generated a z-score/individual centile for the entire cohort including women with pregnancy complications (n = 121,591). The association between maternal BMI and placental weight extremes defined by the new customised versus population-based standard was investigated by logistic regression, as was the association between low placental weight and pregnancy complications. Underweight women had a greater risk of low placental weight [<10thcentile, OR 1.84 (95% CI 1.66, 2.05)] and obese women had a greater risk of high placental weight [>90th centile, OR 1.98 (95% CI 1.88, 2.10)] using a population standard. After customisation, the risk of high placental weight in obese/morbidly obese women was attenuated [OR 1.17 (95% CI 1.09, 1.25)]/no longer significant, while their risk of low placental weight was 59%–129% higher (P < 0.001). The customised placental weight standard was more closely associated with stillbirth, hypertensive disease, placental abruption and neonatal death than the population standard. Our customised placental weight standard reveals higher risk of relative placental growth restriction leading to lower than expected birthweights in obese women, and a stronger association between low placental weight and pregnancy complications generally. Further, it provides an alternative tool for defining placental weight extremes with implications for the placental programming of chronic disease.

scholarly journals Effects of marital status on overall and cancer-specific survival in laryngeal cancer patients: a population-based study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhao Ding ◽  
Deshun Yu ◽  
Hefeng Li ◽  
Yueming Ding
Keyword(s):  
Marital Status ◽  
Cancer Patients ◽  
Laryngeal Cancer ◽  
Cox Regression ◽  
Group Analysis ◽  
Population Based ◽  
Cancer Specific Survival ◽  
Cox Regression Analysis ◽  
Prognostic Effect ◽  
The Difference

AbstractMarital status has long been recognized as an important prognostic factor for many cancers, however its’ prognostic effect for patients with laryngeal cancer has not been fully examined. We retrospectively analyzed 8834 laryngeal cancer patients in the Surveillance Epidemiology and End Results database from 2004 to 2010. Patients were divided into four groups: married, widowed, single, and divorced/separated. The difference in overall survival (OS) and cancer-specific survival (CSS) of the various marital subgroups were calculated using the Kaplan–Meier curve. Multivariate Cox regression analysis screened for independent prognostic factors. Propensity score matching (PSM) was also conducted to minimize selection bias. We included 8834 eligible patients (4817 married, 894 widowed, 1732 single and 1391 divorced/separated) with laryngeal cancer. The 5-year OS and CSS of married, widowed, single, and separated/divorced patients were examined. Univariate and multivariate analyses found marital status to be an independent predictor of survival. Subgroup survival analysis showed that the OS and CSS rates in widowed patients were always the lowest in the various American Joint Committee on Cancer stages, irrespective of sex. Widowed patients demonstrated worse OS and CSS in the 1:1 matched group analysis. Among patients with laryngeal cancer, widowed patients represented the highest-risk group, with the lowest OS and CSS.

scholarly journals Stillbirth outcome capture and classification in population-based surveys: EN-INDEPTH study

2021 ◽  
Vol 19 (S1) ◽  
Author(s):  
Hannah Blencowe ◽  
◽  
Matteo Bottecchia ◽  
Doris Kwesiga ◽  
Joseph Akuze ◽  
...  
Keyword(s):  
Gestational Age ◽  
A Priori ◽  
Healthcare Providers ◽  
Population Based ◽  
Reproductive Age ◽  
Group Discussions ◽  
Cross Sectional ◽  
Vital Status ◽  
Neonatal Deaths ◽  
Adverse Pregnancy

Abstract Background Household surveys remain important sources of stillbirth data, but omission and misclassification are common. Classifying adverse pregnancy outcomes as stillbirths requires accurate reporting of vital status at birth and gestational age or birthweight for every pregnancy. Further categorisation, e.g. by sex, or timing (intrapartum/antepartum) improves data to understand and prevent stillbirth. Methods We undertook a cross-sectional population-based survey of women of reproductive age in five health and demographic surveillance system sites in Bangladesh, Ethiopia, Ghana, Guinea-Bissau and Uganda (2017–2018). All women answered a full birth history with pregnancy loss questions (FBH+) or a full pregnancy history (FPH). A sub-sample across both groups were asked additional stillbirth questions. Questions were evaluated using descriptive measures. Using an interpretative paradigm and phenomenology methodology, focus group discussions with women exploring barriers to reporting birthweight for stillbirths were conducted. Thematic analysis was guided by an a priori codebook. Results Overall 69,176 women reported 98,483 livebirths (FBH+) and 102,873 pregnancies (FPH). Additional questions were asked for 1453 stillbirths, 1528 neonatal deaths and 12,620 surviving children born in the 5 years prior to the survey. Completeness was high (> 99%) for existing FBH+/FPH questions on signs of life at birth and gestational age (months). Discordant responses in signs of life at birth between different questions were common; nearly one-quarter classified as stillbirths on FBH+/FPH were reported born alive on additional questions. Availability of information on gestational age (weeks) (58.1%) and birthweight (13.2%) was low amongst stillbirths, and heaping was common. Most women (93.9%) were able to report the sex of their stillborn baby. Response completeness for stillbirth timing (18.3–95.1%) and estimated proportion intrapartum (15.6–90.0%) varied by question and site. Congenital malformations were reported in 3.1% stillbirths. Perceived value in weighing a stillborn baby varied and barriers to weighing at birth a nd knowing birthweight were common. Conclusions Improving stillbirth data in surveys will require investment in improving the measurement of vital status, gestational age and birthweight by healthcare providers, communication of these with women, and overcoming reporting barriers. Given the large burden and effect on families, improved data must be made available to end preventable stillbirths.

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