Biomedical subjects

Maria Antonietta Stazi

Publications and source records attributed to Maria Antonietta Stazi.

14 recordsLinked to original sources

PubMed2006

Multiple sclerosis in twins from continental Italy and Sardinia: a nationwide study.

Knowledge about the balance between heritable and nonheritable risk in multiple sclerosis (MS) is based on twin studies in high-prevalence areas. In a study that avoided ascertainment limitations and directly compared continental Italy (medium-prevalence) and Sardinia (high-prevalence), we ascertained 216 pairs from 34,549 patients. This gives a twinning rate of 0.62% among MS patients, significantly less than that of the general population. In continental Italy, probandwise concordance was 14.5% (95% confidence interval, 5.1-23.8) for monozygotic and 4.0% (95% confidence interval, 0.8-7.1) for dizygotic twins. Results in Sardinia resemble those in northern populations but in limited numbers. Monozygotic concordance was 22.2% (95% confidence interval, 0-49.3) probandwise, but no concordant dizygotic pairs were identified. A questionnaire on 80 items possibly related to disease cause was administered to 70 twin pairs, 135 sporadic patients, and 135 healthy volunteers. Variables positively (7) or negatively (2) associated with predisposition and concordance in twins largely overlapped and were mainly linked to infection. If compared with previous studies, our data demonstrate that penetrance in twins appears to correlate with MS prevalence. They highlight the relevance of nonheritable variables in Mediterranean areas. The apparent underrepresentation of MS among Italian twins draws attention to protective factors, shared by twins, that may influence susceptibility.

Cohort Studies↗

PubMed2006

[Statistical methods for the analysis of twin data].

The most important statistical methods currently used for the analysis of twin data are described. The main objective of these methods is to estimate the contribution of the genetic and environmental factors to the variability of normal or pathological human traits, by means of the information obtained from monozygotic and dizygotic twin pairs. In this context, the concept of heritability becomes relevant. Not only the simple comparison between monozygotic and dizygotic twins, based on measures such as the concordance and the correlation, but also new and more complex approaches are presented, with a special emphasis on the structural equation models, and a synthetic view on the DF-analysis and the correlated frailty models. Some examples of applications to the data of the Italian Twin Registry are also illustrated.

Data Interpretation, Statistical↗

PubMed2006

[DNA-microarray: new technological approaches on twin studies].

The completion of the Human Genome Project, and the innovations introduced in biotechnology are changing how to study twins. Here, we summarize some molecular studies performed on populations of discordant monozygotic twins (MZ) applying microarrays. Microarrays are an orderly arrangement of high numbers of probes (DNA, RNA or proteins), immobilized onto a matrix. The microarray approach allows a global analysis of gene expression, and therefore might point out the molecular mechanisms of MZ twins' discordance, such as epigenetic mechanisms. The application of microarray to twin studies will help better define, through bioinformatics, the role of genes and environment in the development of human diseases, thus suggesting new diagnostic and therapeutic approaches.

Humans↗

PubMed2005

Genetic and environmental influences on anxiety dimensions in Italian twins evaluated with the SCARED questionnaire.

This study explored the factorial structure of the Italian version of the Screen for Child Anxiety-Related Emotional Disorders questionnaire (SCARED), and investigated the contributions of genetic and environmental influences of individual variation of anxiety dimensions as reported in the SCARED. Three hundred and seventy-eight twin pairs aged 8-17 from the Italian Twin Registry filled in the SCARED through a mail survey. Four, distinct empirical factors, that corresponded closely to the original SCARED subscales of Generalized Anxiety (GAD), Panic (PD), Social Phobia (SP), and Separation Anxiety (SAD) disorder emerged from Exploratory Factor Analysis. The empirically derived scores were analyzed by structural equation modeling; moderate-to-high heritability, without age or sex differences, emerged for all dimensions with the exception of GAD, for which an age effect was found. The DSM-IV anxiety dimensions identified by the SCARED have a psychometric structure that can be replicated in the Italian culture, and are influenced at different extents by genetic and nonshared environmental determinants.

Adolescent↗

PubMed2005

What are the effects of maternal and pre-adult environments on ageing in humans, and are there lessons from animal models?

An open issue in research on ageing is the extent to which responses to the environment during development can influence variability in life span in animals, and the health profile of the elderly in human populations. Both affluence and adversity in human societies have profound impacts on survivorship curves, and some of this effect may be traceable to effects in utero or in infancy. The Barker Hypothesis that links caloric restriction in very early life to disruptions of glucose-insulin metabolism in later life has attracted much attention, as well as some controversy, in medical circles. It is only rarely considered by evolutionary biologists working on phenotypic plasticity, or by biogerontologists studying model organisms such as C. elegans or Drosophila. One crucial mechanism by which animals can respond in an adaptive manner to adverse conditions, for example in nutrition or infection, during development is phenotypic plasticity. Here we begin with a discussion of adaptive plasticity in animals before asking what such phenomena may reveal of relevance to rates of ageing in animals, and in humans. We survey the evidence for effects on adult ageing of environmental conditions during development across mammalian and invertebrate model organisms, and ask whether evolutionary conserved mechanisms might be involved. We conclude that the Barker Hypothesis is poorly supported and argue that more work in human populations should be integrated with multi-disciplinary studies of ageing-related phenomena in experimental populations of different model species that are subjected to nutritional challenges or infections during pre-adult development.

Adaptation, Physiological↗

PubMed2005

Risk factors for congenital hypothyroidism: results of a population case-control study (1997-2003).

OBJECTIVE: To identify risk factors for permanent and transient congenital hypothyroidism (CH). DESIGN: A population-based case-control study was carried out by using the network created in Italy for the National Register of Infants with CH. METHODS: Four controls were enrolled for each new CH infant; 173 cases and 690 controls were enrolled in 4 years. In order to distinguish among risk factors for permanent and transient CH, diagnosis was re-evaluated 3 years after enrollment when there was a suspicion of transient CH being present. Familial, maternal, neonatal and environmental influences were investigated. RESULTS: An increased risk for permanent CH was detected in twins by a multivariate analysis (odds ratio (OR) = 12.2, 95% confidence interval (CI): 2.4-62.3). A statistically significant association with additional birth defects, female gender and gestational age >40 weeks was also confirmed. Although not significant, an increased risk of CH was observed among infants with a family history of thyroid diseases among parents (OR = 1.9, 95% CI: 0.7-5.2). Maternal diabetes was also found to be slightly associated with permanent CH (OR = 15.7, 95% CI: 0.9-523) in infants who were large for gestational age. With regard to transient CH, intrauterine growth retardation and preterm delivery were independent risk factors for this form of CH. CONCLUSION: This study showed that many risk factors contribute to the aetiology of CH. In particular, our results suggested a multifactorial origin of CH in which genetic and environmental factors play a role in the development of the disease.

Adult↗

PubMed2005

Concentration of elements in serum of patients affected by multiple sclerosis with first demyelinating episode: a six-month longitudinal follow-up study.

Twenty-six chemical elements and oxidative status were determined in serum of 12 patients with first demyelinating episode and brain magnetic resonance imaging compatible with the disease at different time points. Quantifications of Al, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Si, Sn, Sr, V, Tl, W, Zn and Zr, as well as of serum oxidative status and antioxidant capacity were carried out. The results were compared with values obtained from healthy subjects living in the same geographic area. Concentration variability, expressed as coefficient of variation (CV), was evaluated over a six months longitudinal follow-up. The CV was higher for Li and Pb, while showed minimal variation for Ca, Cu, Mg and Zn--elements strictly body regulated. Significant difference (p < or = 0.05) in mean concentrations of Ba, Ca, Cd, Cr, Li, Mn, Mo, Ni, Sb, Si, Sn and Zr between patients at time 0 and controls was also found.

Adult↗

PubMed2005

Discriminant analysis to study trace elements in biomonitoring: an application on neurodegenerative diseases.

Quantification of 26 elements was performed in blood of patients affected by neurodegenerative pathologies, i.e., Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS), and of a control group to study the potential role of blood elements as markers for the different neurodegenerations. A multivariate discriminant analysis (stepwise method) was applied to determine the best set of variables to discriminate among subjects with different health status. Preliminary results show three classification functions of seven elements, namely Ca, Co, Cu, Fe, Ni, Pb and Zr.

Adult↗

PubMed2003

Heritability of adult body height: a comparative study of twin cohorts in eight countries.

A major component of variation in body height is due to genetic differences, but environmental factors have a substantial contributory effect. In this study we aimed to analyse whether the genetic architecture of body height varies between affluent western societies. We analysed twin data from eight countries comprising 30,111 complete twin pairs by using the univariate genetic model of the Mx statistical package. Body height and zygosity were self-reported in seven populations and measured directly in one population. We found that there was substantial variation in mean body height between countries; body height was least in Italy (177 cm in men and 163 cm in women) and greatest in the Netherlands (184 cm and 171 cm, respectively). In men there was no corresponding variation in heritability of body height, heritability estimates ranging from 0.87 to 0.93 in populations under an additive genes/unique environment (AE) model. Among women the heritability estimates were generally lower than among men with greater variation between countries, ranging from 0.68 to 0.84 when an additive genes/shared environment/unique environment (ACE) model was used. In four populations where an AE model fit equally well or better, heritability ranged from 0.89 to 0.93. This difference between the sexes was mainly due to the effect of the shared environmental component of variance, which appears to be more important among women than among men in our study populations. Our results indicate that, in general, there are only minor differences in the genetic architecture of height between affluent Caucasian populations, especially among men.

Adult↗

PubMed2003

Longevity studies in GenomEUtwin.

Previous twin studies have indicated that approximately 25% of the variation in life span can be attributed to genetic factors and recent studies have also suggested a moderate clustering of extreme longevity within families. Here we discuss various definitions of extreme longevity and some analytical approaches with special attention to the challenges due to censored data. Lexis diagrams are provided for the Danish, Dutch, Finnish, Italian, Norwegian, and Swedish Twin registries hereby outlining possibilities for longevity studies within GenomEUtwin. We extend previous analyses of lifespan for the Danish 1870-1900 twin cohorts to include the new 1901-1910 cohorts, which are consistent with the previous findings. The size of the twin cohorts in GenomEUtwin and the existence of population-based, nationwide health and death registers make epidemiological studies of longevity very powerful. The combined GenomEUtwin sample will also allow detailed age-specific heritability analyses of lifespan. Finally, it will provide a resource for identifying unusual sibships (i.e., dizygotic twin pairs) where both survived to extreme ages, as a basis for discovering genetic variants of importance for extreme survival.

Adult↗

PubMed2002

The Italian Twin Project: from the personal identification number to a national twin registry.

The unique opportunity given by the "fiscal code", an alphanumeric identification with demographic information on any single person residing in Italy, introduced in 1976 by the Ministry of Finance, allowed a database of all potential Italian twins to be created. This database contains up to now name, surname, date and place of birth and home address of about 1,300,000 "possible twins". Even though we estimated an excess of 40% of pseudo-twins, this still is the world's largest twin population ever collected. The database of possible twins is currently used in population-based studies on multiple sclerosis, Alzheimer's disease, celiac disease, and type 1 diabetes. A system is currently being developed for linking the database with data from mortality and cancer registries. In 2001, the Italian Government, through the Ministry of Health, financed a broad national research program on twin studies, including the establishment of a national twin registry. Among all the possible twins, a sample of 500,000 individuals are going to be contacted and we expect to enrol around 120,000 real twin pairs in a formal Twin Registry. According to available financial resources, a sub sample of the enrolled population will be asked to donate DNA. A biological bank from twins will be then implemented, guaranteeing information on future etiological questions regarding genetic and modifiable factors for physical impairment and disability, cancers, cardiovascular diseases and other age related chronic illnesses.

Aging↗

PubMedDate not supplied

Association between heterozygosity for HFE gene mutations and hepatitis viruses in hepatocellular carcinoma.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are strong and independent risk factors for hepatocellular carcinoma (HCC) development. Patients with hereditary hemochromatosis (HH) are considered at risk of developing cancer. However, the interaction between HFE gene mutations and hepatitis viruses for HCC development has not been systematically searched for. To assess the interaction between HFE gene mutations and exogenous risk factors in the risk of HCC occurrence, a case-only approach, in which just a series of patients is enrolled, was used. Three hundred three cirrhotic patients (231 males, 72 females) from five liver units in different geographic areas of Italy, who developed HCC during regular follow-up between January 1999 and March 2003, and whose blood DNA was available, were analyzed. In all subjects, hepatitis B surface antigen (HBsAg), anti-HCV and HFE gene mutations were assayed; alcohol intake was recorded by history. The interaction between HFE genotypes and hepatitis viruses for HCC was estimated by multivariate analysis adjusting for the confounding effect of alcohol intake, area of residence and months of follow-up. Of the 303 HCC cases, 12 (4.0%) were heterozygous for the C282Y mutation, 93 (30.7%) for the H63D, and 198 (65.3%) homozygous for the wild allele. Multivariate analysis showed that C282Y heterozygous males were 3.8-fold (95% CI=1.0-15.2) more likely to be HBV positive and that H63D heterozygous females were 6.0-fold (95% CI=1.2-113.8) more likely to be HCV positive than wild type subjects. In conclusion, given the association between C282Y mutation and HBV infection in male patients with HCC, a careful evaluation and follow-up should be considered in the C282Y-positive subjects with hepatitis B virus related liver disease. The interaction between the H63D mutation and HCV, observed only in women, may reflect a higher sensitivity to H63D-induced iron metabolism abnormalities and a reduced antioxidant capability in the presence of an even minor increase of iron which may occur as a consequence of the coexistence of hepatitis C infection and heterozygosity for HH.

Antibodies, Viral↗

PubMedDate not supplied

Clinical evolution of celiac disease in Italy 1982-2002.

GOALS: The aim of this work is to assess how the clinical features of celiac disease have changed in Italy after the widespread introduction of serologic tests in 1993. STUDY: Twenty Italian Clinical Centers collected information from 1982 until 2002 on 1968 patients older than 18 years diagnosed with celiac disease. RESULTS: The results show that the incidence of atypical and silent cases of celiac disease has increased after the wider availability of serological test, which has allowed earlier diagnosis and treatment. CONCLUSIONS: This paper provides a view on the evolution of the clinical features of celiac disease in Italy over 2 decades. The relevance of the analysis is supported by the fact that Italy is one of the countries with the highest incidence of celiac disease. These findings underline the importance of a timely diagnosis of celiac disease.

Adult↗

PubMedDate not supplied

[Twins in biomedical research and the creation of the "National Twin Registry"].

Twins are a valuable resource for the study of complex traits. The twin method is substantially based on the comparison between correlations and concordance in monozygotic (MZ) and dizygotic (DZ) twins and allows several applications in biomedical and molecular genetic research. It allows either the qualitative and quantitative evaluation of the influences that genetic and environmental factors exert on phenotypes or the estimation of trait variability. Moreover, classical genetic linkage analysis is more powerful if performed in DZ twins. However, the twin method has some pitfalls, such as the necessity that collected samples be representative of both twin and general population. For this reason, over the last few years, a number of Countries have established population-based twin registers, which guarantee the maximum level of representation and, consequently, are of extreme value for epidemiological studies. Italy is also implementing a national twin register. The following is the description of the procedure that led to the establishment of the Italian Twin Registry.

Databases, Factual↗