Is the frequency of multiple sclerosis increasing in Mexico?

Multiple sclerosis in Central America and Caribbean countries: frequency and clinical characterization of an emergent disease

Background

Multiple Sclerosis (MS) is a common neurological disease among white populations of European origin. Frequencies among Latin Americans continue to be studied, however, epidemiologic, and clinical characterization studies lack from Central American and Caribbean countries. Ethnicity in these countries is uniformly similar with a prevalent Mestizo population.

Methods and results

Data from January 2014 to December 2019 from Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Dominican Republic, and Aruba on demographic, clinical, MRI and phenotypic traits were determined in coordinated studies: ENHANCE, a population-based, retrospective, observational study on incidence and clinical characteristics, and from the subgroup with MS national registries (Aruba, Dominican Republic, Honduras, and Panama), data on prevalence, phenotypes and demographics. Expanded Disability Status Scale (EDSS), and therapeutic schemes were included. ENHANCE data from 758 patients disclosed 79.8% of Mestizo ethnicity; 72.4% female; median age at onset 31.0 years and 33.2 at diagnosis. The highest incidence rate was from Aruba, 2.3-3.5 × 100,000 inhabitants, and the lowest, 0.07-0.15 × 100,000, from Honduras. Crude prevalence rates per 100,000 inhabitants fluctuated from 27.3 (Aruba) to 1.0 (Honduras). Relapsing MS accounted for 87.4% of cases; EDSS <3.0 determined in 66.6% (mean disease duration: 9.1 years, SD ± 5.0); CSF oligoclonal bands 85.7%, and 87% of subjects hydroxyvitamin D deficient. Common initial therapies were interferon and fingolimod. Switching from interferon to fingolimod was the most common escalation step. The COVID-19 pandemic affected follow-up aspects of these studies.

Conclusion

This is the first study providing data on frequencies and clinical characteristics from 8 countries from the Central American and Caribbean region, addressing MS as an emergent epidemiologic disorder. More studies from these areas are encouraged.

Multiple sclerosis in indigenous peoples of the Americas: A systematic review of incidence, prevalence, and outcomes

INTRODUCTION

The incidence, prevalence and outcomes of multiple sclerosis (MS) are unclear in Indigenous Peoples (IP) who are more likely to be underrepresented in research. We completed a systematic review of MS in IP of the Americas.

METHODS

A systematic review was conducted using PubMed, Web of Science, and Cochrane databases as well as references of retrieved papers. Inclusion criteria were: peer-reviewed publications (January 1990- December 2021), incidence, prevalence, or clinical outcome measures of MS in self-identified IP in the Americas. Incidence, prevalence, morbidity and mortality data were summarized and stratified by location and year of publication. Study quality was evaluated by risk of bias or confounding.

RESULTS

Out of 416 titles, thirteen studies met inclusion criteria. Four studies evaluated incidence, seven prevalence, three clinical outcomes and one mortality. Most studies were completed in Canada or the United States (US). Incidence rates per 100,000 ranged from 0.48 (in US Indian Health Service records) to 8.15 (First Nations Manitoban Canadians). Prevalence ranged from 0 (Lacandonian Mexicans and Panamanians) to 188.5 (First Nations Manitoban Canadians). Incidence and prevalence are consistently lower in IP than comparator White populations. IP with MS were reported to have higher disability and faster disability progression than non-Indigenous comparators. MS-related mortality is low compared to White people.

CONCLUSION

There is an absence of high-quality studies evaluating MS in IP. Available evidence indicates low, but increasing incidence and prevalence of MS in IP of the Americas. IP with MS may have worse disability than non-Indigenous comparators. Future studies should evaluate the factors influencing the increases in incidence and prevalence as well as better characterize possible disparities in MS care among IP.

Vitamin D status, proinflammatory cytokines and bone mineral density in Mexican people with multiple sclerosis

BACKGROUND

Vitamin D (VD) has been classically associated with calcium homeostasis and bone mineral density since it has a key role on mineralization and resorption. Immunomodulatory effects have been attributable to VD; low concentrations of VD have been associated with elevation of inflammatory markers. Inflammatory autoimmune diseases, such as multiple sclerosis (MS), a chronic neurodegenerative suffering, whose etiology is still unknown, is directly related to an increase in pro-inflammatory cytokines such as interleukin 17 and interleukin 1β who play an important role in this physiopathology. Nowadays, even though additional studies have linked MS's clinical signs with low VD concentration, there is scarce information of this association in people from regions with sufficient sun exposure. The aim of this study was to evaluate serum VD and cytokine concentrations, and bone density, in Mexican people with MS.

METHODS

Vitamin D (25OHD), interleukin 1β, interleukin 6 and interleukin 17 concentrations of twenty-five volunteers with MS were determined by enzyme-linked immunosorbent assay. Bone mineral density and body composition assessment was performed by dual energy X-Ray absorptiometry.

RESULTS

A mean concentration of 17.3 ± 4.6 ng/ml of 25OHD was obtained, in a range of 5.15 to 25.71 ng/ml; when international advisory bodies thresholds were applied 76% of the participants exhibited some degree of VD inadequacy. Pro-inflammatory markers were detectable among the participants: interleukin 1β in 100%, interleukin 6 in 64%, whereas interleukin 17 was found in 24% of the volunteers. Bone mineral density below the expected for the age was found in 8% of the participants, with lumbar spine as the most affected anatomic region. Non-significant correlations were found between VD and bone mineral density (Z-score) or pro-inflammatory markers.

CONCLUSION

Although non-significant correlations were found between VD and bone mineral density or cytokines, it is important to highlight that an important percentage of our participants exhibited some degree of VD inadequacy, an unknown fact for them, since these are not included in routine clinical evaluations. The low concentrations of VD among this sample regardless of annual UVB sun exposure may suggest the involvement of endogenous and not environmental factors. Further works are needed in order to deepen the physiological causes and effects of VD deficiency in people with MS.

The global prevalence of familial multiple sclerosis: an updated systematic review and meta-analysis

BACKGROUND

Considering that many recent studies have reported the prevalence of familial multiple sclerosis (FMS), we performed an updated meta-analysis of the worldwide prevalence of FMS by the addition of recent publications.

METHODS

A search in PubMed, Scopus, the ISI Web of Science, and Google Scholar was undertaken up to 20 December 2020. The inclusion criteria were based on the CoCoPop approach (condition, context, and population). Meta-analysis of the qualified studies was conducted by comprehensive meta-analysis ver. 2 software.

RESULTS

The pooled prevalence of MS in relatives of 16,179 FMS cases was estimated to be 11.8% (95% CI: 10.7-13) based on a random-effects model. The pooled mean age of disease onset in adult probands was calculated to be 28.7 years (95% CI: 27.2 ± 30.2). Regarding 13 studies that reported the data of FMS in pediatrics (n = 877) and adults (n = 6636), the FMS prevalence in pediatrics and adults was 15.5% (95% CI: 13.8-17.4) and 10.8% (95% CI: 8.1-14.2), respectively. The prevalence of FMS in affected males (n = 5243) and females (n = 11,503) was calculated to be 13.7% (95% CI: 10.1-18.2) and 15.4% (95% CI: 10.3-22.4), respectively. The odds ratio of male/female in FMS cases was not statistically significant (OR = 0.9; 95% CI: 0.6-1.2, P = 0.55). Subgroup analysis demonstrated a significant difference in the prevalence of FMS between the geographical areas (P = 0.007). The meta-regression model indicated that the prevalence of FMS is lower with higher latitude and higher MS prevalence (P < 0.001). In contrast, meta-regression based on prevalence day was not statistically significant (P = 0.29).

CONCLUSIONS

The prevalence of FMS is higher in the pediatric group than that of adults, distinct between geographical areas, and diminishes with the increment of MS prevalence and latitude. Also, the symptoms initiate relatively at younger ages in the FMS cases. Interestingly, our analysis unveiled that FMS is not more prevalent in men than women and the risk of MS development in relatives is not higher when the affected proband is male.

Multiple sclerosis in Iran: An epidemiological update with focus on air pollution debate

BACKGROUND

Multiple sclerosis (MS), as the most common neurologic disorder of the central nervous system, with growing incidence and prevalence worldwide and in the Middle East. This article aimed to find out the potential relationship between MS and air pollution in Iran.

METHODS

By assessing the published articles on MS and air pollution in Iran, the situation of MS as well as air/soil pollution in Iran was clarified. Then, studies on air pollution and its potential effect on Iranian MS patients were checked until 2020.

RESULTS

The MS prevalence is distributed across Iran Provinces with highest rates in Isfahan, located in the center of Iran. The higher rates of MS in Isfahan and Tehran (the Metropolitan) might be due to industrial pollution of these cities, but this hypothesis is not true for non-industrial provinces. Based on the published atlas of MS in Iran, it seems that there is a high-risk "belt" from northwest to southeast.

CONCLUSION

There are many risk factors of MS in Iran including age, gender, Vitamin D deficiency, smoking, and air pollution. The potential main risk factor of MS might be air pollution considering Isfahan and Tehran provinces. However, Chahar Mahal and Bakhtiary Province, with non-industrial nature, has the second highest MS rates which does not follow this hypothesis.

RELEVANCE FOR PATIENTS

By finding the air pollution as the main potential risk factor of MS in big provinces including Isfahan and Tehran, its effect of this factor can also be considered during diagnosis and treatment.

Clinical and demographic features in Iranian multiple sclerosis patients: a systematic review and meta-analysis

Aim: This study was conducted to determine the clinical and demographic features in Iranian multiple sclerosis (MS) patients including clinical courses, positive MS family history, disability and age of disease onset. Materials & methods: All stages of the study were reported according to the PRISMA guidelines. A systematic review of published literature in Persian and English journals with a comprehensive search was conducted on English international databases including Scopus, PubMed/Medline, Cochrane Library, Science Direct, Web of Science, Embase, PsycINFO, as well as the Google Scholar search engine and national databases. Results: The prevalence of clinical courses of relapsing remitting, primary progressive, secondary progressive and relapsing progressive in Iranian patients with MS was 77.1% (95% CI: 72.2–81.3), 6.2% (95% CI: 4.1–9.2), 9.5% (95% CI: 6.8–13.1) and 0.4% (95% CI: 0.2–0.8), respectively. Positive family history of MS in Iranian MS patients was 8.9% (95% CI: 6.9–11.4). The mean age of disease onset was 28.9 years (95% CI: 27.8–30.1). Conclusion: The results of this meta-analysis in an Iranian population can provide useful information for neurologists and healthcare.

Multiple Sclerosis: A Global Concern with Multiple Challenges in an Era of Advanced Therapeutic Complex Molecules and Biological Medicines

Multiple sclerosis (MS) has become a common neurological disorder involving populations previously considered to be infrequently affected. Genetic dissemination from high- to low-risk groups is a determining influence interacting with environmental and epigenetic factors, mostly unidentified. Disease modifying therapies (DMT) are effective in treating relapsing MS in variable degrees; one agent is approved for primary progressive disease, and several are in development. In the era of high-efficacy medications, complex molecules, and monoclonal antibodies (MAB), including anti-VLA4 (natalizumab), anti-CD52 (alemtuzumab), and anti-CD20 (ocrelizumab), obtaining NEDA (no evidence of disease activity) becomes an elusive accomplishment in areas of the world where access to MS therapies and care are generally limited. Countries' income and access to public MS care appear to be a shared socioeconomic challenge. This disparity is also notable in the utilization of diagnostic tools to adhere to the proposed elements of the McDonald Criteria. The impact of follow-on medications ("generics"); injectable non-biological complex drugs (NBCD), oral sphingosine-1-phosphate receptor modulators, and biosimilars (interferon 1-a and 1-b), utilized in many areas of the world, is disconcerting considering these products generally lack data documenting their efficacy and safety. Potential strategies addressing these concerns are discussed from an international point of view.

Increasing prevalence of familial recurrence of multiple sclerosis in Iran: a population based study of Tehran registry 1999-2015

BACKGROUND

Tehran is the capital of Iran with an increasing multiple sclerosis (MS) prevalence. A retrospective population-based study was conducted to evaluate the trends of MS prevalence in Tehran.

METHODS

A population-based survey was conducted for the period 1999 to 2015, based on Iranian MS Society (IMSS) registry system of Tehran, the capital city of Iran. Point regression analysis was applied on MS trend data to find annual percent change (APC). The logistic regression analysis was used to estimate the odds ratio (OR) for individual variables in order to assess factors associating with familial recurrence of MS. P values < 0.05 were considered significant.

RESULTS

MS prevalence has significantly increased during the study period from 1999 to 2015 (56.22 per 100,000). Total point prevalence of MS was 115.94 per 100,000 persons in 2015 compared to general population. Positive family history of MS was observed among 12.4% of patients. The strongest association amongst first-degree relatives was found in siblings, p value ≤ 0.001.

CONCLUSION

MS prevalence is rising in Tehran and this city is one of the regions with highest MS prevalence in Asia. In this sample, the largest proportion of relatives with MS were found among first-degree relatives, particularly siblings. Familial recurrence correlated with relative type.

Worldwide prevalence of familial multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Several studies have suggested that the existence of a history of multiple sclerosis (MS) in family, is one of the predisposing factors for MS. Based on our knowledge, the review and estimation of the prevalence of familial multiple sclerosis (FMS) in the world has not been reported up to now. This study is a systematic review and a meta-analysis of FMS prevalence in the world.

METHODS

Two researchers searched "epidemiology" or "prevalence" or "incidence" and "familial multiple sclerosis" as relevant keywords in international databases such as PubMed, web of science and Scopus up to 2016. MedCalc Version 15.8 was used to estimate the pooled prevalence of FMS. (PROSPERO ID = CRD42016033016) RESULTS: From the 184 total articles found from 1954 to 2016, we pooled and analyzed the data of 17 final eligible studies, according to the inclusion criteria. The prevalence of FMS was estimated as 12.6% within a total sample size of 14,619 MS patients in the world as of 95% confidence interval (CI: 9.6-15.9).

CONCLUSION

We detected significant heterogeneity from Hungary to Saskatchewan for FMS prevalence that was not latitude and ethnicity dependent. This highlighted the accumulation effects of genetic and environment on FMS prevalence. Pooled prevalence of FMS in MS population was calculated 12.6% by random effect in the world.

MS in self-identified Hispanic/Latino individuals living in the US

Self-identified Hispanic/Latino individuals living with multiple sclerosis (MS) in the continental United States (US) are a diverse group that represents different cultural and ancestral backgrounds. A marked variability in the way MS affects various subgroups of Hispanics in the US has been observed. We reviewed and synthesized available data about MS in Hispanics in the US. There are likely a host of multifactorial elements contributing to these observations that could be explained by genetic, environmental, and social underpinnings. Barriers to adequate MS care in Hispanics are likely to include delivery of culturally competent care and social and economic disadvantages. Considerable efforts, including the formation of a national consortium known as the Alliance for Research in Hispanic Multiple Sclerosis (ARHMS), are underway to help further explore these various factors.

Comparing epidemiology and baseline characteristic of multiple sclerosis and neuromyelitis optica: A case-control study

BACKGROUND

Autoimmune syndromes such as Multiple Sclerosis (MS) and Neuromyelitis Optica (NMO) are chronic, demyelinating diseases of the central nervous system which usually affect young adults. Both environmental risk factors and genetic susceptibility have been proposed to explain the etiology of these diseases. The aim of this study was to compare epidemiology and possible risk factors in MS and NMO in Tehran, Iran.

METHOD

A population-based incident case-control study was performed in Tehran based on a study conducted on1513 MS patients from Iranian MS Society registry center of Tehran, from 2014 to 2015, and 83 NMO patients diagnosed with NMO in 2015 at Sina hospital, a tertiary care referral center in Tehran. The random digit dialing (RDD) methods were established to select 400 population-based controls. A checklist was designed to cover the epidemiological variables to estimate the possible risk factors for MS and NMO based on a questionnaire designed for multinational case-control studies of environmental risk factors in multiple sclerosis. Structured face to face interviews with cases, and telephone interviews with controls were conducted by trained interviewers to collect data. The multiple logistic regression analysis was done via SPSS package.

RESULTS

The adjusted odds ratio (OR) estimate of MS for females compared to males was (OR =1.47; 95% CI: 1.12, 1.95), and it was (OR=1.54; 95% CI: 1.17, 2.02) for people aged 18-27 years compared to younger ones aged 28-37 years. The adjusted OR estimate of NMO for people aged over 48 years compared to those aged 28-37 years was (OR=3.49; 95% CI: 1.59, 7.64). The point estimates were greater than eight-fold increased risk associated with MS among patients with a positive familial history 8.80 (95% CI: 4.10, 18.90).

CONCLUSION

The results of this study reveal that the risk of MS is significantly higher in female and younger people in comparison to NMO. Having positive family history of MS can increase the risk of MS substantially. The findings of the study indicated that factors that predict susceptibility to MS, including a positive history of MS in relatives, do not appear to have any association with NMO.

The High Prevalence of the Varicella Zoster Virus in Patients With Relapsing-Remitting Multiple Sclerosis: A Case-Control Study in the North of Iran

BACKGROUND

Multiple sclerosis (MS) is the most common neurological autoimmune disease, characterized by multifocal areas of inflammatory demyelination within the central nervous system. It has been hypothesized that the stimulation of the immune system by viral infections is the leading cause of MS among susceptible individuals.

OBJECTIVES

The aim of this study was to investigate the prevalence of the varicella zoster virus (VZV) in patients with relapsing-remitting multiple sclerosis.

PATIENTS AND METHODS

Plasma and peripheral blood mononuclear cells (PBMCs) collected from MS patients (n = 82) and controls (n = 89) were screened for the presence of anti-VZV antibodies and VZV DNA by the ELISA and PCR methods. DNA was extracted from all samples, and VZV infection was examined by the PCR technique. Statistical analysis was used to investigate the frequency of the virus in MS patients and a healthy control group.

RESULTS

Of all the MS patients, 78 (95.1%) and 21 (25.6%) were positive for anti-VZV and VZV DNA, respectively. Statistical analysis of the PCR results showed a significant correlation between the abundance of VZV and MS disease (P < 0.001). However, there was no significant correlation between the abundance of anti-VZV antibodies and MS disease by the ELISA method.

CONCLUSIONS

These results support the hypothesis that VZV may contribute to MS in establishing a systemic infection process and inducing an immune response.

Mental Health and Health-Related Quality of Life in Multiple Sclerosis Caregivers in Mexico

BACKGROUND

Multiple sclerosis (MS) rates are increasing in Latin America, and caregiving for an individual with MS is associated with poorer mental and physical health outcomes. No existing research has examined the relation between mental health and health-related quality of life (HRQOL) in MS caregivers in Latin America.

METHODS

The present study examined the association between mental health (Patient Health Questionnaire-9, Satisfaction with Life Scale, Rosenberg Self-esteem Scale, State-Trait Anxiety Inventory) and HRQOL (36-item Short Form Health Status Survey) in 81 Mexican MS caregivers.

RESULTS

A canonical correlation analysis uncovered a large, significant overall association between mental health and HRQOL, with 52.7% of the variance shared between the two sets of constructs. When individual canonical loadings were examined in this analysis, the most substantial pattern that emerged was between depression and general health. Four regressions controlling for demographic variables found that HRQOL uniquely accounted for 19.0% of the variance in caregiver anxiety, 32.5% in depression, 13.5% in satisfaction with life, and 14.3% in self-esteem.

CONCLUSIONS

These findings demonstrated a strong association between HRQOL and mental health, which points to directions for future studies on interventions for MS caregivers, particularly in Mexican and other Latino populations.

Familial forms of multiple sclerosis and neuromyelitis optica at an MS center in Rio de Janeiro State, Brazil

OBJECTIVE

To describe familial forms of demyelinating diseases from an MS referral center in Río de Janeiro State, Brazil.

METHODS

A descriptive, cross-sectional study was done to identify familial IIDD cases in Hospital da Lagoa, a public hospital where 75% of patients with IIDD who live in Rio de Janeiro state, located in the Southeast region of Brazil, are referred. The diagnoses of all consecutive patients followed in 2011 were reviewed to apply new diagnostic criteria (Wingerchuk et al., 2008). The diagnosis of IIDD was confirmed based on clinical history, neurological examination, MRI of the skull and spinal cord, CSF analysis and investigation of IgG NMO antibodies. The cases that had at least one other relative with IIDD were selected for the study.

RESULTS

Familial forms were found only in the multiple sclerosis (MS) and neuromyelitis optica syndrome (NMOSD) categories. 23 MS families were identified, 60.86% with first degree kinship. It has a Caucasian preponderance, 90% of whom were white. The frequency of early onset was 15% and 20% of the MSf cases have progressive primary course.

CONCLUSION

The frequency of familial cases of IIDD was 6.12% among MS patients and 2.8% in NMO spectrum syndromes.

Genomewide admixture study in Mexican Mestizos with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a complex immune-mediated disease. It has been suggested that genetic factors could explain differences in the prevalence among ethnic groups. To know whether genetic ancestry is a potential risk factor for MS in Mexican patients and to identify candidate genes for the susceptibility to the disease we conducted an initial trial of genome-wide analysis.

METHODS

29 patients with diagnosis of definitive MS and 132 unrelated healthy controls were genotyped using the Affymetrix human 6.0 array. After QC procedures, ancestry determination and a preliminary case-control association study were performed.

RESULTS

We identified significant differences in the European ancestry proportion between MS cases and controls (33.1 vs. 25.56, respectively; p=0.0045). Imputation analysis in the MHC region on chromosome 6 showed a signal with a significant level (p<0.00005) on the HLA-DRB region. Additionally, a preliminary association analysis highlighted the ASF1B as novel candidate gene participating in MS.

CONCLUSION

Our data suggest that European ancestry is a risk factor to develop MS in Mexican Mestizo population. Conversely, indigenous ancestry of Asian origin seems to confer protection. Further studies with more MS cases are needed to confirm these findings.

The participation of varicella zoster virus in relapses of multiple sclerosis

OBJECTIVE

Recent studies have documented the apparent participation of varicella zoster virus (VZV) in the etiopathogenesis of multiple sclerosis (MS). The present study aimed to corroborate the possible presence of VZV during exacerbations of MS.

DESIGN

Fifty-three patients with definite MS were included; of them, 31 were studied during the first week of a clinical relapse, whereas 16 were studied during remission; 6 patients with progressive MS were also studied. Genes from 5 herpes viruses: varicella zoster, herpes simplex 1 and 2, Epstein-Barr and herpes 6 were studied by polymerase chain reaction in cerebrospinal fluid and in peripheral blood mononuclear cells (PBMC). As controls 21 patients with inflammatory or functional neurological disorders were included.

RESULTS

DNA from varicella zoster virus was found in the CSF from all MS patients studied during relapse (100%) and in the PBMC from 28 of them (90%). However, VZV DNA was found in the CSF only in 5 MS patients studied during remission (31%) and in the PBMC from 3 of them (19%). VZV DNA was also found, but in lower amounts, in the CSF (83%) and PBMC (33%) from patients with progressive MS. In contrast, VZV was not found either in CSF or in PBMC from controls. Results from the other herpes viruses tested were similar in MS patients and in controls.

CONCLUSIONS

Our results corroborate the conspicuous, but ephemeral presence of VZV during relapses of MS and support the idea of VZV involvement in the etiopathogenesis of MS. Recent epidemiological and molecular studies as well as reports of severe VZV infections triggered by specifically induced immunosuppression during therapy of MS give additional support to this potential association.

Socioeconomic factors in childhood and the risk of multiple sclerosis

In a national cohort comprising 1.5 million Danes born from 1966 to 1992, we studied the association between childhood socioeconomic status (SES) and the risk of multiple sclerosis (MS) from 1981 to 2007 using information about household income and parental educational levels at the person's 15th birthday. The association between childhood SES and MS was evaluated using MS incidence rate ratios with 95% confidence intervals obtained in log-linear Poisson regression analyses. We found no strong association between childhood SES and MS but did observe a tendency toward a reduced risk of MS among children from households with more highly educated parents, particularly mothers. Children whose mothers had a secondary (rate ratio = 0.95, 95% confidence interval: 0.86, 1.04) or higher (rate ratio = 0.86, 95% confidence interval: 0.76, 0.97) education had reduced risks of MS (5% and 14%, respectively) compared with children of mothers with a basic education (P for trend = 0.02). Results were practically unchanged in an analysis restricted to persons aged 15-29 years, among whom the possible effect of own SES on MS risk is considered limited. Overall, SES in childhood seems of no major importance for the subsequent risk of MS; however, offspring of well-educated mothers may be at a slightly reduced risk of MS.

Multiple sclerosis in Hispanics: a study of clinical disease expression

Background: Hispanics living with multiple sclerosis (MS) in the United States are not well defined.

Objective: To describe the clinical characteristics of MS among Hispanic Whites (HW) in Southern California with those of non-Hispanic Whites (NHW).

Methods: We performed a medical chart review to identify all cases of HW with MS ( n = 125) who were treated at our institution during a 1-year period. We also identified cases of NHW with MS (100 NHW) treated at those clinics. All HW patients were interviewed to ascertain ancestry including detailed migration history. Disease progression was assessed by ambulatory disability and defined as Expanded Disability Status Scale (EDSS) score ≥6.

Results: Compared with NHW, HW were more likely to have a relapsing–remitting form of MS and a younger age of onset (28.4 ± 0.97 years) with presenting symptoms of optic neuritis and transverse myelitis. However, overall ambulatory disability did not differ between HW and NHW. Migration to the US at age >15 years was associated with increased risk of disability in HW.

Conclusions: HW living in the USA may be at risk of developing MS at an earlier age compared with NHW. Migration history can play an important role in the management of HW with MS.

Varicella zoster virus and relapsing remitting multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disorder; however, little is known about the triggering factors of the abnormal immune response. Different viruses from the herpes family have been mentioned as potential participants. Here, we review the evidences that support the association of varicella zoster virus (VZV) with MS. Epidemiological studies from geographical areas, where incidence of MS has increased in recent decades, pointed out a high frequency of varicella and zoster in the clinical antecedents of MS patients, and also laboratory investigations have found large quantities of DNA from VZV in leucocytes and cerebrospinal fluid of MS patients restricted to the ephemeral period of MS relapse, followed by disappearance of the virus during remission. The above observations and the peculiar features of VZV, mainly characterized by its neurotropism and long periods of latency followed by viral reactivation, support the idea on the participation of VZV in the etiology of MS. However, as with reports from studies with other viruses, particularly Epstein Barr virus, conflicting results on confirmatory studies about the presence of viral gene products in brain tissue indicate the need for further research on the potential participation of VZV in the etiology of MS.

Association of a history of varicella virus infection with multiple sclerosis

OBJECTIVE

To analyze the association of a previous history of varicella virus infection with multiple sclerosis (MS) and its subtypes.

MATERIAL AND METHODS

We performed a case-control study including 126 cases and 157 controls. Subjects were divided into subgroups according to MS subtype and the history of varicella virus infection along with other variables was assessed.

RESULTS

History of varicella zoster virus (VZV) infection was positive in 42% of controls and 66% of MS cases (p<or=0.001). Patients with a history of VZV infection had a threefold risk increase of having MS. Regarding MS subtypes, relapsing-remitting (RR) MS had four times the risk and secondary progressive had a threefold increase in risk when compared with control patients.

CONCLUSIONS

An association between varicella infection history and MS was found, particularly in the RR subtype.

On the viral hypothesis of multiple sclerosis: Participation of varicella-zoster virus

Recent studies, including our own, have accumulated evidence suggesting the etiological participation of varicella-zoster virus in multiple sclerosis. If confirmed, complex issues of individual susceptibility and immunopathogenesis would have to be unveiled.

Comparative features of the epidemiology of multiple sclerosis and Parkinson's disease: Environmental factors of potential etiological importance

Multiple sclerosis (MS) and Parkinson's disease (PD) are diseases of unknown cause. The etiology of MS is usually considered to be due to a number of potential biological agents while the etiology of PD is usually associated with toxic agents. Despite these differences, both pathologies have strong epidemiological similarities. A comparative analysis is performed of the epidemiology of MS and PD. Potential causal factors for PD may include dopamine-like pharmacological agents. It is proposed that potential causal agents such as certain drugs plus certain vaccines could explain rationally the epidemiology of MS. Ecology and genetics could not be the appropriate lines of research in the etiology of MS/PD because they are supported only in part by the epidemiology.

Varicella-zoster virus at relapses of multiple sclerosis

The possible participation of different herpes viruses was studied during exacerbations of multiple sclerosis (MS). We searched for the presence of DNA from the following herpes viruses: varicella zoster virus (VZV), herpes-simplex viruses 1 and 2; Epstein-Barr virus (EBV) and human herpes-virus-6 (HHV6) in mononuclear cells from patients with MS during relapse (n = 40), MS during remission (n = 131) and controls (n = 125). Additionally, immune cells containing viral antigens were quantified by flow cytometry, and VZV load was determined by real time PCR in 2 MS patients at various times during relapse and remission. DNA from VZV was found in 95% of MS patients during relapse and in 17% during remission; all controls were negative; by contrast, DNA from HHV6 was found in 24% of MS patients during relapse and in 2% during remission; DNA from herpes simplex viruses was not found in any subject; and DNA from EBV was found in a similar percentage of subjects from all groups. Sequential quantification of VZV-load showed a curve that increased during relapse and disappeared at remission. Also, VZV antigens were found inside a large number of immune cells from MS patients during relapse as compared with MS patients on remission and controls. In the typical forms of VZV infection, varicella and herpes-zoster, DNA from VZV is found in mononuclear cells exclusively during brief periods at the beginning of the active infection, but not during latency; thus, the conspicuous presence of VZV during relapses of MS may indicate a period of active infection and suggests the participation of VZV in the pathogenesis of MS.

Western and Asian features of multiple sclerosis in Mexican Mestizos

OBJECTIVES

The objective of this study was to compare the clinical expression of MS in Mexican Mestizos with that of patients of European or Asian descent; as well as to compare the annual frequency of new cases with that observed in the previous decades.

PATIENTS AND METHODS

All patients with diagnosis of definite MS seen at the National Institute of Neurology and Neurosurgery of Mexico from January 1993 to December 2003 were studied (n=312). Sociodemographic and clinical characteristics were compared with reports of patients from either Western or Asian origin; the long-term disability score was analyzed according to gender, age of onset of MS and the initial symptom.

RESULTS

The clinical expression of MS in Mexican Mestizos shares some characteristics with both, Asian and Western forms of MS indicating that the genetic composition of Mexican Mestizos participates in the clinical expression of the disease. Also, at the prevalence date, the mean age of patients and the duration of the disease were lower in our patients than in MS patients from endemic countries suggesting a true increasing incidence in recent times, rather than only improved case ascertainment.

CONCLUSIONS

Clinical expression of MS in Mexican Mestizos shows the coexistence of some features common in European and in Asian cases.

Mediterranean and Amerindian MHC class II alleles are associated with multiple sclerosis in Mexicans

OBJECTIVES

Human leukocyte antigen (HLA)-DRB1, DQA1, DQB1 allele typing was performed in Mexicans Mestizos with multiple sclerosis (MS) to define the HLA class II alleles associated with the disease in this population.

METHODS

Patients (n = 51) diagnosed according to the Poser criteria and a group of 173 unrelated healthy subjects were studied. PCR-SSOP and PCR-SSP were used for genotyping.

RESULTS

Fifty five percent of the patients were females. The mean age at disease onset was 27 years. A relapsing-remitting disease was the most frequent type of MS (67%). A significant association of DRB1*0403 (OR = 5.68) with MS was shown. DRB1*0802 was also involved in susceptibility (OR = 2.41). An excess of DRB1*0802 homozygotes was observed in patients (P = 0.005), this genotype being in genetic equilibrium in controls.

CONCLUSIONS

Two novel class II associations are described in Mexicans with MS: DRB1*0403 and DRB1*0802. Both alleles share with DRB1*1501, valine-86 and negatively charged amino acids, in the DRB1-anchoring motif of pocket 4.

Epidemiology of multiple sclerosis in Kuwait: new trends in incidence and prevalence

The epidemiology of multiple sclerosis (MS) is undergoing dramatic changes; MS is occurring with increased frequency in many parts of the world. In this retrospective study, we examined the changes in incidence and prevalence of MS in Kuwait in the period between 1993 and 2000. We analyzed the records of patients with clinically defined and laboratory supported MS. The total incidence rate increased from 1.05/100,000 population in 1993 to 2.62/100,000 in 2000. The increased incidence of MS was most pronounced among Kuwaiti women (from 2.26/100,000 in 1993 to 7.79/100,000 in 2000. The total prevalence rate increased from 6.68/100,000 in 1993 to 14.77/100,000 in 2000. It was much higher for Kuwaitis (31.15/100,000), as compared to non-Kuwaitis (5.55/ 100,000), in a complete reversal of the pattern observed before 1990. The prevalence was also higher among Kuwaiti women (35.54/100,000), as compared with Kuwaiti men (26.65/100,000). In conclusion, the incidence and prevalence of MS in Kuwait has increased between the early and late 1990s with no signs of leveling off. In a geographic area that was previously associated with low prevalence, local environmental factors may be responsible for these dramatic changes.

Varicella, ephemeral breastfeeding and eczema as risk factors for multiple sclerosis in Mexicans

OBJECTIVE

It has been suggested that the incidence of multiple sclerosis (MS) in Mexico and other countries of Latin America has increased steadily for the last two decades. We made a thorough search of antecedents on MS patients that could be potential risk factors.

METHODS

A case-control study was conducted using a questionnaire that included demographic, nutritional, infectious and personal antecedents previously identified in other reports as possible risk factors for MS.

RESULTS

The frequency of varicella, ephemeral breastfeeding and eczema in the medical history of MS patients were significant when compared with controls; all appeared to be mutually additive. However, they were unrelated with clinical characteristics or disease severity.

CONCLUSION

During the last decades, breastfeeding has been abandoned in large segments of society and the incidence of varicella and childhood eczema keeps a north-south gradient similar to that described for MS. These factors may participate in the sharp increase of MS in countries like Mexico traditionally considered as an area of very low incidence.

Brain tumors in Mexico: characteristics and prognosis of glioblastoma

BACKGROUND

Frequency and clinical characteristics of brain tumors have been studied in several populations from different genetic backgrounds; their peculiarities in the Mexican mestizo population shed light on the descriptive and comparative epidemiologic analysis of the genetic participation in brain tumors.

METHODS

To analyze the frequency of intracranial neoplasms at the National Institute of Neurology and Neurosurgery of Mexico between 1987 and 1994, demographic, clinical, surgical, and neuropathological records were reviewed and compared with other reports. Glioblastoma cases were followed to investigate survival and prognostic factors.

RESULTS

In a seven-year period 1,776 patients with brain tumors were treated; 419 (24%) had pituitary adenoma; 586 (33%) had glioma. Of the latter, 165 had glioblastoma multiforme, representing 28% of all gliomas and 9% of all neoplasms. Mean survival for glioblastoma was 16 months and the longest mean survival was obtained in patients with radical neurosurgical resection plus radiotherapy and chemotherapy. Cumulative analysis showed that 41% of patients survived less than one year, 39% from 1 to 2 years, 12% from 2 to 3 years and 8% more than three years. Factors that showed prognostic significance were age, therapeutic approach, tumor size, and pre- and postoperative clinical status (p < 0.05).

CONCLUSIONS

This study comprises the largest series on the frequency of brain tumors in a Latin American population. When compared with other studies, the proportion of glioma and glioblastoma among brain neoplasms was low whereas pituitary adenoma was high. Mean survival for glioblastoma was similar to other reports; in these patients, the overall therapeutic response is still far from satisfactory.

The prevalence of multiple sclerosis in the Hungarian city of Szeged

OBJECTIVES

The aim of this study was to determine the prevalence of multiple sclerosis in a population in South Hungary.

METHODS

The diagnosis was established with the aid of the Poser diagnostic criteria and the degree of physical disability was determined on the Kurtzke expanded disability status scale (EDSS). The present medical state (EDSS score) was determined from outpatient clinical control tests. The prevalence, the average age at onset of the disease and the proportions of the various clinical forms were calculated, and the patients' disability status was estimated.

RESULTS

In 1996, the prevalence was 65/100,000, and the incidence from January 1, 1995 through December 31, 1996 was 7/100,000/year.

DISCUSSION

During a period of 2 years, the number of diagnosed patients has almost doubled. The disease can be recognized in an early stage with a minimal neurological deficit. The development of the diagnostics necessitates re-examinations with modern diagnostic procedures. During the last 3 years, the general practitioner system has been reorganized, and the working relationships between the clinic and family doctors have developed considerably. A comparison of the present findings with those in other countries with a similar climate revealed very similar prevalence data.

Optic neuritis progressing to multiple sclerosis

We report a partially retrospective and longitudinal study of patients with optic neuritis (ON) that developed multiple sclerosis (MS). We assessed clinical features or factors that might differentiate these patients from those with ON that did not develop MS. Of the cases followed, 110 (67%) were found to have an idiopathic origin of the disease; whereas 55 (33%) were found to develop it secondary to another disease. Of the 110 idiopathic cases, 13 (12%), developed MS over an average of 2 years. The results of these patients in the laboratory analyses of blood and CSF as well as the results of the MRI and evoked potential studies, were significantly different from the ON patients without MS. We conclude that the percentage of patients with ON in our sample that developed MS is similar to that found in Japan and is relatively low in comparison to other reports.