Biomedical subjects

Corrado Fagnani

Publications and source records attributed to Corrado Fagnani.

7 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↗

PubMed2004

Heritability of biochemical kidney markers and relation to survival in the elderly--results from a Danish population-based twin study.

BACKGROUND AND AIM: We performed a twin study to assess the relative contribution of genetic and environmental factors to serum levels of urea, creatinine, urate and sodium in a population of 688 elderly twins (73-95 years). Furthermore, we tested the association between these biochemical values and mortality to examine the consequence of an abnormal biochemical kidney parameter in an aging population. RESULTS: A third to a half of the variation in the biochemical kidney tests is due to genetic factors except for creatinine in males. Survival analysis show that all four parameters influence mortality and values below reference interval for urea and urate have a more pronounced impact on survival [hazard ratios (95% confidence interval): 2.32 (1.03-5.26) and 3.56 (1.46-8.69), respectively] than values above [1.20 (0.87-1.64) and 1.50 (1.11-2.02), respectively]. Increased creatinine (above 130 micromol/l) and decreased sodium (below 136 mmol/l) also have a significant impact on survival with hazard ratios on 1.83 (1.13-2.95) and 1.56 (1.22-1.99), respectively. Between 5% and 44% of the measured values are outside the established reference interval. CONCLUSION: This study provides evidence for the importance of genetic factors in determining the biochemical kidney parameters in an aging population. Furthermore, our data shows that abnormal kidney parameters are common in older adults and results in a significant increase in mortality risk.

Aged↗

PubMed2003

Sex differences in heritability of BMI: a comparative study of results from twin studies in eight countries.

Body mass index (BMI), a simple anthropometric measure, is the most frequently used measure of adiposity and has been instrumental in documenting the worldwide increase in the prevalence of obesity witnessed during the last decades. Although this increase in overweight and obesity is thought to be mainly due to environmental changes, i.e., sedentary lifestyles and high caloric diets, consistent evidence from twin studies demonstrates high heritability and the importance of genetic differences for normal variation in BMI. We analysed self-reported data on BMI from approximately 37,000 complete twin pairs (including opposite sex pairs) aged 20-29 and 30-39 from eight different twin registries participating in the GenomEUtwin project. Quantitative genetic analyses were conducted and sex differences were explored. Variation in BMI was greater for women than for men, and in both sexes was primarily explained by additive genetic variance in all countries. Sex differences in the variance components were consistently significant. Results from analyses of opposite sex pairs also showed evidence of sex-specific genetic effects suggesting there may be some differences between men and women in the genetic factors that influence variation in BMI. These results encourage the continued search for genes of importance to the body composition and the development of obesity. Furthermore, they suggest that strategies to identify predisposing genes may benefit from taking into account potential sex specific effects.

Adolescent↗

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

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↗

PubMedDate not supplied

[Regression methods and causal inference: structural equations models].

The estimate of correlations among observed outcomes is crucial in biomedical research, especially when the aim of the study is to infer, from the magnitude of these correlations, the causal influence of certain, sometimes latent, factors. In such situations, a typical regression approach, known as "structural equation models" (SEM), which was introduced in the 1970s, becomes significant. These models allow hypotheses to be formulated quite clearly, thanks to some explicit and rigorous graphical representations, on which the "path analysis" is based. SEM, which were initially used in economics, have in the past decade been applied in a wide variety of fields, especially in genetic epidemiology. It's in this field that SEM are extraordinarily effective, representing a simple yet powerful means of estimating the contribution of genes and the environment to the phenotypic expression of a given disease. To this end, data on twins are particularly useful, and in this case the correlation between the outcomes describes the extent of similarity of the twin phenotypes. From this standpoint, SEM undoubtedly constitute one of the most promising statistical tools for family studies and quantitative genetic research. The method can be easily extended to traditional epidemiology, and some interesting applications have already been developed in occupational and social epidemiology. In this paper, we describe in detail the SEM approach and discuss the use of these models in genetic epidemiology, using twin studies as an example. We also discuss the application of SEM in fields other than genetic research.

Causality↗