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In 1996, the prevalence of multiple sclerosis (MS) for the metropolitan area of Buenos Aires using the capture-recapture method was estimated to be between 14 and 19.8 cases per 100,000 inhabitants. The aim of this study was to update the prevalence to 2014 following the same methodology. Methods Gran Buenos Aires is the denomination that refers to the megalopolis comprised by the autonomous city of Buenos Aires and the surrounding conurbation of the province of Buenos Aires. The study was carried out taking December 2014 as the prevalence month. We used the capture-recapture method to estimate the prevalence of MS cross-matching registries from 6 MS Centers from the metropolitan area of Buenos Aires. Log-linear model Poisson regression was used to estimate the number of affected MS patients not detected by any of the 6 sources considered. Results 1035 registries were obtained from the 6 lists from 910 different patients detected. The population of the area based on 2010 census was 12,806,866, the number of MS cases estimated amongst source interactions were 4901. The estimated prevalence was 38.2 per 100,000 inhabitants (95% CI 36.1–41.2). Conclusion The study is an update almost 20 years after the first one in the area showing a significant increase in the previous reported prevalence. Our findings are in line with previous studies performed in other regions of the world. [ABSTRACT FROM AUTHOR]

Several studies in multiple sclerosis (MS) suggest a trend of increasing disease frequency in women during the last decades. A direct comparison of gender ratio trends among MS populations from Argentina remains to be carried out. The objective of the study was to compare gender ratio trends, over a 50-year span in MS populations from Argentina. Methods: multicenter study that included patients from 14 MS Centers of Argentina. Patients with definite MS with birth years ranging from 1940 to 1989 were included. Gender ratios were calculated by five decades based on year of birth and were adjusted for the F/M born-alive ratio derived from the Argentinean national registry of births. The F/M ratios were calculated using a multivariate logistic regression per five decades by the year of birth approach. Analyses were performed using Stata 10.1. Results: 1069 patients were included. Gender ratios showed a significant increase from the first to the last decade in the whole MS sample (from 1.8 to 2.7; p value for trend = 0.023). The Gender ratio did not show differences considering MS subtype. Conclusion: our study showed a modest increase of the F/M ratio (from 1.8 to 2.7) over time among patients affected by MS in Argentina. [ABSTRACT FROM AUTHOR]

Objective: The present study was undertaken to determine the incidence of MS in a health maintenance organization from Buenos Aires, the largest populated area in Argentina. Methods: Population was all members of a hospital-based health maintenance organization who were affiliated since January 1992 up to December 2007. Each person was followed contributing time at risk since January 1992 or enrollment date to the final date. Patients with definite diagnosis according to Poser’s criteria were included. Incidence density was calculated with 95% confidence intervals. Results: A total of 145 000 patients were followed for a total of 1 021 515 person-years, of whom 18 developed the disease. Incidence density (ID): 1.76 /100 000 person-years (95% CI: 1.1–2.8/100 000 person-years). Conclusion: The incidence density of 1.76 per 100 000 suggests a low-median risk area for MS. This study constitutes the first of its kind to cover data of MS incidence in Argentina. [ABSTRACT FROM AUTHOR]

Background: Scarce data exist about multiple sclerosis (MS) prevalence in South America. The objective of the study is to determine the prevalence of MS in a high populated area from Argentina (Greater Buenos Aires Metropolitan area) using the capture-recapture methodology. Methods: Greater Buenos Aires is the generic denomination that refers to the megalopolis comprised by the autonomous city of Buenos Aires and the surrounding conurbation of the province of Buenos Aires. The study was carried out taking July 1996 as the prevalence month. We used capture-recapture method to estimate the prevalence of MS cross matching registries from four MS Centers. Results: A total of 803 registries were obtained from the four lists. Log-linear model for capture-recapture method was used to analyze the data. The population of the area based on the 1990 census was 12 594 974; the number of MS cases estimated amongst sources interactions were between 1833 and 2359; the prevalence estimated ranged from 14 to 19.8 cases per 100 000 inhabitants. Conclusions: This is the first study to provide epidemiological data on the prevalence of MS in a large population in Argentina (Greater Buenos Aires Metropolitan area). Further epidemiological studies will clarify the true prevalence of MS in South America. [ABSTRACT FROM AUTHOR]

Hundreds of publications dealing with the prevalence of multiple sclerosis (MS) throughout the world exist, but little data have been published from South America. Epidemiological studies of MS vary according to environmental, racial and genetic factors; a better understanding of MS in South America would help us to elucidate the disease pattern in this population. The aim of this study is to review the evidence relevant to MS epidemiology in South America. We performed a systematic review of articles of MS epidemiology in South America, with special emphasis on those providing information on the incidence and prevalence of MS (population-based studies). Six papers provided information on MS epidemiology. One paper used the capture-recapture methodology, while the remainder employed traditional methods to collect the data. Population-based studies showed an MS prevalence rate ranging from 1.48 to 17 per 100 000 inhabitants. Available data suggest that the prevalence of MS is lower in South America than in developed countries. The reason for this observation is unknown. Some investigators suggest that certain environmental factors like sun exposure and vitamin D supplementation or the called ‘hygiene hypothesis’ may protect this population. Future studies will contribute to elucidate the etiology of that difference. [ABSTRACT FROM AUTHOR]

Old age groups have different risk profile and stroke features compared to younger groups. Our aim was to examine the risk factor profile and stroke subtype in patients older than 80 years with ischemic stroke. Data of 535 patients with ischemic stroke or transient ischemic attack (TIA) were prospectively recorded. Cardiovascular risk factors and stroke subtype in individuals aged 80 years or older were compared with patients under 80. Of 535 patients a total of 179 were over 80 years (33.5%). The mean age was 84.4 ± 4.4 years (61.8%; 111 women). The most common risk factors included hypertension (82.7%) and hyperlipidemia (40.2%). Lacunar stroke was the most frequent subtype of stroke (41.7%). When the groups were compared, we observed the following risk factors more frequently in the group older than 80: female patients ( P = <0.001), hypertension (OR = 1.62), atrial fibrillation (OR = 2.64); whereas diabetes (OR = 0.54), hyperlipidemia (OR = 0.57), smoking (OR = 0.17) and obesity (OR = 0.58) were more frequent in the group younger than 80. In the old group we found a high incidence of ischemic stroke in women. We also found a higher frequency of hypertension and atrial fibrillation. The available and future epidemiological data will provide a better knowledge about the effect of typical risk factors in old people. [ABSTRACT FROM AUTHOR]

Background: The association of multiple sclerosis (MS) with HLA DR subtypes, and particularly human leukocyte antigen (HLA)-DRB1*15 has been a consistent finding across nearly all Caucasian MS populations. In South America, scarce data exist about this issue. As the complete characterization of the HLA association range around the world is important to understand the role of this locus in MS susceptibility, we analyzed the frequency of HLA-DRB1* allelic groups in an MS population in Argentina. Methods: HLA-DRB1 locus was genotyped using PCR and sequence-specific primer amplification in 61 MS patients born in Buenos Aires, Argentina and 1216 healthy controls. Allele frequencies were compared between groups. Results: The HLA-DRB1*15 allele frequency significantly differed between controls and patients (13.5% and 33.9% respectively, P < 0.001, OR 2.51, 95% CI: 1.7–3.0). The other allele frequencies did not show significant differences between patients and controls. Conclusions: The present HLA class II population study is in accordance with other Caucasian MS surveys which have found that HLA-DRB1*15 allele is strongly associated with MS disease. In Argentina, this is the first study performed to analyze the association of HLA-DRB1*15 and MS susceptibility in a Caucasian population and therefore contributes with new data to the immunogenomic global MS map. [ABSTRACT FROM AUTHOR]