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Background: Global variation in the incidence of multiple sclerosis (MS) is generally ascribed to differences in genetic and environmental risk factors. Here we investigate temporal trends in the incidence of MS and related disorders in British Columbia, Canada, from 1986 to 2010, focusing particularly on the Asian ethnic subpopulation., Methods: A longitudinal database was screened to identify newly diagnosed cases of MS and related disorders, including neuromyelitis optica and clinically isolated syndromes. Age-standardized, sex-specific mean annual incidence was calculated for the Asian and non-Asian population of British Columbia for 5-year intervals from 1986 to 2010. Temporal changes and cohort differences in incidence rates and demographic characteristics were evaluated., Results: During this period, the incidence of MS and related disorders in the non-Asian population remained relatively unchanged, from 10.41 (95% confidence interval [CI]: 9.87-10.97) to 9.91 (95% CI: 9.46-10.39) per 100,000 (p=0.167). In contrast, incidence in the Asian population doubled during the same period. This increase was driven by a precipitous rise in the incidence of MS in females from 0.71 (95% CI: 0.01-1.50) to 2.08 (95% CI: 1.43-2.91) per 100,000 (p=0.004), including both Canadian-born and immigrant Asians. The incidence of neuromyelitis optica did not change significantly during this period., Conclusions: The incidence of MS may be increasing among females in the Asian ethnic population of British Columbia.

Multiple sclerosis (MS) affects up to 1/500 Canadians. The University of British Columbia MS Clinic (UBC Clinic) is the only MS clinic in Canada (and likely internationally) that routinely offers genetic counseling to patients and their families. A typical session includes the collection of family history and demographic data, discussion of the inheritance of MS, interpretation of family-specific recurrence risks and psychosocial counseling. The aims of this study were to explore patients': 1) expectations of the genetic counseling session; 2) understanding of the etiology of MS (both pre and post-session); and 3) post-session perceptions of genetic counseling. A two-part questionnaire to assess genetic counseling services was distributed before and after sessions to all consenting patients seen during the period October 1, 2008 to February 28, 2009 inclusive. Sixty-two completed questionnaires were analysed. Genetic counseling was found to significantly increase the number of individuals who were able to correctly identify the etiology of MS (p < 0.001). Patient satisfaction with genetic counseling was high, with an average satisfaction score of 32.4/35 (92.6 %). Of those who provided comments (n = 42/60) regarding the usefulness of the genetic counseling session, 95.2 % reported it useful (n = 40/42). Findings suggest that genetic counseling is effective in increasing patients' knowledge of the etiology of MS and is viewed by patients as a useful service. Based on the high level of positive feedback regarding genetic counseling by the study sample, this study suggests that the services provided by genetic counselors may be beneficial for patients with MS seen in other centers.

Background: There is a well-documented increase in the risk of multiple sclerosis (MS) when migrating from a region of low prevalence to one of high prevalence., Objective: We present here an investigation of MS prevalence and candidate environmental and genetic risk factors among Iranian immigrants to British Columbia (BC), Canada., Methods: MS cases of Iranian ancestry were ascertained from a population-based Canadian study. We collected blood samples for genetic and serological analyses, and administered a personal history questionnaire to the cases., Results: The crude prevalence of MS in this population of Iranian ancestry was 287/100,000 (95% CI: 229 - 356/100,000). MS cases were more likely to have a history of infectious mononucleosis (odds ratio (OR) = 7.5; p = 0.005) and smoking (OR = 17.0; p < 0.0001), as compared to healthy controls from previous studies in Iran. Cases were also more likely than controls to have been born between April and September (OR = 2.1; p = 0.019)., Conclusion: The prevalence of MS among Iranian immigrants to Canada is greater than the overall prevalence of MS in Iran by a factor of at least four, and is similar to that recently observed among Iranian immigrants in other western nations. No major genetic susceptibility variants were identified, suggesting the environment in Canada may be what is increasing the risk of MS in this population., (© The Author(s) 2014.)

Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. Several studies have shown an association between smoking and MS risk. Here, in a population-based Canadian cohort, we investigate the relationship between personal and maternal smoking exposure and the risk of MS. Using the longitudinal Canadian database, 3,157 MS cases and 756 spouse controls were administered questionnaires on active and passive smoking history. Mothers of cases and controls were also asked about their smoking exposure during pregnancy. The MS cases were more likely to have smoked than spouse controls (odds ratio 1.32, 95 % confidence interval 1.10-1.60, p = 0.003). This association was driven by an excess of ever-smokers in male MS cases. No association was seen with maternal active or passive smoking exposure during pregnancy. Ever-smoking is associated with increased MS risk in males. Further work is needed to understand the mechanism underlying this association.

When contemplating a pregnancy, women treated for multiple sclerosis (MS) with a disease-modifying drug must decide to discontinue their medication before conception or risk exposing their unborn child to potential drug toxicity. Few studies exist as reference for patients and physicians, and of those available, the majority are less than ideal due to real-world constraints, ethical issues and methodological shortcomings. The authors provide a brief summary of existing animal and human data with current recommendations regarding the safety of IFN-β, glatiramer acetate, natalizumab, mitoxantrone, fingolimod and teriflunomide during pregnancy and lactation in women with MS. We also assess the quality, strengths and limitations of the existing studies including challenges with study design. The investigation of outcomes such as spontaneous abortion and congenital anomalies are highlighted with potential methodological improvements for future studies on drug safety in pregnancy suggested. The authors explore the pharmacokinetics and pharmacodynamics of the MS disease-modifying drugs for their possible mechanistic role in fetal harm and discuss the potential role of clinical trials. Future pharmacovigilance studies should continue to pursue multicenter collaboration with an emphasis on appropriate study design.

Objective: To systematically review the literature regarding safety of disease-modifying drug (DMD) use during pregnancy on perinatal and developmental outcomes in offspring of patients with multiple sclerosis (MS)., Methods: A PubMed and EMBASE search up to February 2012 was conducted with a manual search of references from relevant articles. Selected studies were evaluated using internationally accepted criteria., Results: Fifteen studies identified 761 interferon β-, 97 glatiramer acetate-, and 35 natalizumab-exposed pregnancies. Study quality ranged from poor to good; no study was rated excellent. Small sample sizes limited most studies. Compared with data for unexposed pregnancies, fair- to good-quality prospective cohort studies reported that interferon β exposure was associated with lower mean birth weight, shorter mean birth length, and preterm birth (<37 weeks), but not low birth weight (<2,500 g), cesarean delivery, congenital anomaly (including malformation), or spontaneous abortion. Fewer studies of fair quality were available for glatiramer acetate and natalizumab. Glatiramer acetate exposure was not associated with lower mean birth weight, congenital anomaly, preterm birth, or spontaneous abortion. Natalizumab exposure did not appear to be associated with shorter mean birth length, lower mean birth weight, or lower mean gestational age. No studies examined mitoxantrone or fingolimod exposure. One study of paternal DMD use during conception found no effect on gestational age or birth weight. Few studies examined longer-term developmental outcomes., Conclusion: Further studies are needed to determine the potential risks associated with preconceptional and in utero DMD exposure in patients with MS. Discontinuation of DMDs before conception is still recommended.

Objective: Pregnancy has a well documented effect on relapse risk in multiple sclerosis (MS). Prospective studies have reported a significant decline by two-thirds in the rate of relapses during the third trimester of pregnancy and a significant increase by two-thirds during the first 3 months postpartum. However, it is unclear as to whether there are any long term effects on disability., Methods: Data were collated from clinical records and family histories systematically collected from the University of British Columbia MS Clinic., Results: Clinical and term pregnancy data were available from 2105 female MS patients. MS patients having children after MS onset took the longest time to reach an Expanded Disability Status Scale (EDSS) score of 6 (mean 22.9 years) and patients having children before MS onset were the quickest (mean 13.2 years). However, these effects were not related to term pregnancy and were fully accounted for by age of MS onset., Conclusions: Pregnancy had no effect on the time to reach an EDSS score 6. As MS predominantly affects women of childbearing age, women with MS can be reassured that term pregnancies do not appear to have any long term effects on disability.

The precise aetiology of multiple sclerosis (MS) is yet to be conclusively determined, but both genes and environment and interactions thereof are important. It has been suggested that early life child exposure influences MS susceptibility. Here, in a population-based cohort, we investigated whether infant day care attendance influences the subsequent risk to develop MS. We identified 379 MS index cases and 101 spousal controls, all of whom were a single child (i.e. they had no biological sibs, half-sibs, step-sibs, adopted sibs) from the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). Frequency of infant day care attendance was compared for index cases and controls and the results were not statistically significant. Exposure to other infants during early childhood thus does not appear to be a risk factor for MS., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: There is a strong maternal parent-of-origin effect in determining susceptibility to multiple sclerosis (MS). One hypothesis is that an abnormal intrauterine milieu leading to impaired fetal development could plausibly also result in increased susceptibility to MS. A possible marker for this intrauterine insult is the presence of a non-fatal congenital anomaly., Methods: We investigated whether or not congenital anomalies are associated with MS in a population-based cohort. We identified 7063 MS index cases and 2655 spousal controls with congenital anomaly information from the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS)., Results: The frequency of congenital anomalies were compared between index cases and controls. No significant differences were found., Conclusions: Congenital anomalies thus do not appear to be associated with MS. However, we did not have complete data on types and severity of congenital anomalies or on maternal birth history and thus this study should be regarded as preliminary.

Autoimmune mechanisms are thought to have a major role in the pathogenesis of multiple sclerosis (MS) and vitamin D is hypothesised to contribute to disease susceptibility. Cow's milk allergy (CMA) is a common childhood allergy arising from an immune system imbalance and can also lead to vitamin D deficiency due to dairy food avoidance. Here, we investigated whether or not CMA influences the subsequent risk to develop MS in a population-based cohort. We identified 6638 MS index cases and 2509 spousal controls with CMA information from the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). Frequency of CMA was compared between index cases and controls. No significant differences were found. Childhood CMA thus does not appear to be a risk factor for MS., (Copyright 2009 Elsevier B.V. All rights reserved.)

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.)

Multiple sclerosis (MS) is a complex neurological trait. Allelic variation in the MHC class II region exerts the single strongest effect on MS genetic risk. The clinical onset of the disease is extremely variable, and can range from the first to the ninth decade of life. Epidemiological studies have suggested a modest genetic component to the age of onset (AO) of MS. Previous studies have shown that HLA-DRB1*1501 may be associated with a younger AO. Here, we sought to uncover any effect of HLA-DRB1*1501 on the AO of MS in a large Canadian cohort. A total of 1816 MS patients were genotyped for HLA-DRB1. Patients carrying HLA-DRB1*1501 were shown to have a small, but significantly lower, AO than patients without the allele (P=0.03). HLA-DRB1*1501 was also shown to reduce the mean AO in both progressive and relapsing forms of the disease. An investigation of parent-of-origin effects indicated that the lower AO for HLA-DRB1*1501 patients arises from maternally transmitted HLA-DRB1*1501 haplotypes (maternal HLA-DRB1*1501 mean AO=28.4 years, paternal=30.3 years; P=0.009). HLA-DRB1*1501 exerts a modest, but significant effect on the AO of all forms of MS. Parent-of-origin effects at the MHC are further implicated in MS disease pathogenesis.

The ages of onset in multiple sclerosis cases span more than 7 decades. Data are presented for affected relative pairs from a Canadian population base of 30,000 multiple sclerosis index cases (1993-2008). The effects of genetic sharing, parent of origin, intergenerational versus collinear differences, and gender on the ages of onset were evaluated in the following concordant pairs: monozygotic twins (n = 29), dizygotic twins (n = 10), siblings (n = 614), first cousins (n = 405), half siblings (n = 29), parent/child (n = 285), and aunt/uncle/niece/nephew (avunculars) (n = 289). Fisher's z test assessed intraclass correlation (r) for ages of onset. Correlations for monozygotic twins, dizygotic twins, full siblings, and first cousins were 0.60, 0.54, 0.20, and 0.10, respectively. Dizygotic twins resembled monozygotic twins more than siblings. The age-of-onset correlation for maternal half siblings (r = 0.37) was higher than that for paternal half siblings (r = 0.26), consistent with other observations suggesting an intrauterine environmental effect on multiple sclerosis risk. Intergenerational comparisons are complicated by substantial increases of multiple sclerosis incidence over time. Genetic loading (familial vs. sporadic cases) did not generally influence the age of onset, but correlation of age of onset in multiple sclerosis relative pairs was proportional to genetic sharing. A maternal parent-of-origin effect on the age of onset in collinear generations was suggested.

The article discusses a study which investigates the prevalence and genetic risk factors of multiple sclerosis (MS) among Iranian immigrants to British Columbia. Topics include the collection of blood samples for serological analyses and used questionnaire, the characteristics and causes of MS, and cases of MS patients with smoking history.