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Background: Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. A clear parent-of-origin effect has been shown in several populations. Advanced maternal age has been shown to be associated with adverse outcomes in offspring including chromosomal abnormalities. Advanced paternal age is associated with a number of adult onset disorders including schizophrenia and bipolar disorder. In a population-based Canadian cohort, we investigated whether there is any difference in parental age at birth for MS index cases compared to spouse controls. Methods: Using the longitudinal Canadian database, we identified 5,681 MS index cases and 1,249 spouse controls with complete information on parental dates of birth, thereby allowing a calculation of the maternal and paternal ages at the birth of their children (MS index cases and spouse controls). Results: No significant difference in maternal or paternal age at birth was found (average MS index case maternal age at birth = 27.3 years, average spouse control maternal age at birth = 27.0 years, p = 0.13; average MS index case paternal age at birth = 30.7 years, average spouse control paternal age at birth = 30.2 years, p = 0.37). Conclusions: Parental age at birth is not associated with susceptibility to MS. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. Several studies have attempted to correlate exposure to viral illness with the subsequent development of MS. Here in a population-based Canadian cohort, we investigate the relationship between prior clinical infection or vaccination and the risk of MS. Methods: Using the longitudinal Canadian database, 14,362 MS index cases and 7,671 spouse controls were asked about history of measles, mumps, rubella, varicella and infectious mononucleosis as well as details about vaccination with measles, mumps, rubella, hepatitis B and influenza vaccines. Comparisons were made between cases and spouse controls. Results: Spouse controls and stratification by sex appear to correct for ascertainment bias because with a single exception we found no significant differences between cases and controls for all viral exposures and vaccinations. However, 699 cases and 165 controls reported a history of infectious mononucleosis (p < 0.001, corrected odds ratio 2.06, 95% confidence interval 1.71–2.48). Females were more aware of disease history than males (p < 0.001). Conclusions: The data further confirms a reporting distortion between males and females. Historically reported measles, mumps, rubella, varicella and vaccination for hepatitis B, influenza, measles, mumps and rubella are not associated with increased risk of MS later in life. A clinical history of infectious mononucleosis is conspicuously associated with increased MS susceptibility. These findings support studies implicating Epstein-Barr virus in MS disease susceptibility, but a co-association between MS susceptibility and clinically apparent infectious mononucleosis cannot be excluded. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. A clear maternal effect has been shown in several population-based studies. This parent-of-origin effect could result from factors operating during gestation. It has been shown that a low birth weight increases the risk of several adult-onset diseases. In a population-based Canadian cohort, we investigated whether there is any difference in birth weight for MS index cases compared to spousal controls. Methods: Using the longitudinal Canadian database, we identified 6,188 MS index cases and 1,640 spousal controls with birth weight information. Additionally, data were available on 164 discordant MS twins. The birth weight was compared between index cases and controls as well as for twin pairs. Results: When stratifying by sex, no significant difference in birth weight was found (average female index case birth weight = 7.23 pounds, average female control birth weight = 7.19 pounds, p = 0.48; average male index case birth weight = 7.56 pounds, average male control birth weight = 7.55 pounds, p = 0.92). Furthermore, there was no difference in birth weight between affected and unaffected twins (average affected twin weight = 5.46 pounds, average unaffected twin weight = 5.44 pounds, p =0.85). Conclusions: The maternal effect in MS aetiology does not appear to act through a route that has an influence on birth weight. As birth weight is a relatively poor marker of fetal development, other factors involved in fetal and early development need to be explored to elucidate the mechanism of the increased MS risk conferred maternally. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The etiopathogenesis of multiple sclerosis (MS) remains unclear. However, genetic factors are believed to be important in disease susceptibility. A methodological approach is presented for a population-based study aimed at investigating MS familial incidence and patterns of familial clustering in Northern Sardinia, Italy, with a reported MS prevalence of 150/100,000 population. Patients with MS since 1965 to the present and known to the MS Register for the province of Sassari will be asked to provide genealogical, comorbid and demographic information. Statistical analyses of the familial risk for MS will depend on the completeness of MS 'age at onset' data for affected individuals and age at the time family history is obtained (or age at death) for unaffected family members. [ABSTRACT FROM AUTHOR]