Incidence and prevalence of multiple sclerosis in southeastern Iran

Background

Based on data available, Iran is located in a low risk area for multiple sclerosis (MS). The objective of the current study is to determine the age and sex adjusted prevalence and incidence of MS in southeastern Iran.

Methods

This cross-sectional case register study was conducted from January to August 2010. Considering that MS affects people aged between 16 and 50 years, we intended to find the incidence and prevalence of MS during this age range. Since all cases in this area are referred to our university hospital for confirmation of diagnosis, misdiagnosis is rare. Population data, based on the censuses carried out in 1996 and 2006, were obtained from the Iranian Bureau of Statistics to determine the number of people at risk.

Results

Totally 206 patients were identified according to the McDonald criteria. In 2009 the age-adjusted prevalence and incidence rates of MS for 16–50 year-old adults were 13.96 and 2.67 per 100,000 persons, respectively. Based on those values; the female to male ratio was 2.18. Between 2006 and 2009, the incidence rates increased 2.4 and 2.7 times in women and men, respectively. In 2009, the prevalence rates among the age ranges of <15, 16–35, 36–50 and ≥51 years were 1.44, 14.34, 12.24 and 1.45 per 100,000 persons, respectively, and the relapsing-remitting type of MS was the most prevalent form (65.8%).

Conclusion

According to the Kurtzke geographical distribution, the authors conclude that the prevalence of MS in southeastern Iran is in the intermediate range, and the incidence rate is showing a faster growth rate, compared to previous years.     

Multiple sclerosis prevalence and possible lead exposure

This study was conducted to estimate the current prevalence of multiple sclerosis (MS) in Jefferson County, Missouri, USA, and to address community concerns about a perceived excess of MS around an active lead smelter. The study population consisted of the residents of Jefferson County, Missouri between 1998 and 2002. An aggressive MS case finding with capture–recapture analysis was used. The spatial clustering was examined using a spatial scan statistic.

The capture–recapture analysis showed the case ascertainment to be 95%. The crude five-year period prevalence of MS in Jefferson County was 105 per 100,000 population (95% confidence interval [CI], 91–121), and 107 per 100,000 (95% CI, 95–119) when age-standardized to the 2000 U.S. population. No significant spatial clusters of MS cases were identified in the study area.

The estimates of MS prevalence in Mid-western community of USA appeared to be comparable to estimates from other areas of similar latitude in the United States and Western Europe. The MS cases did not appear to cluster around the lead smelter.     

Multiple sclerosis in New Zealand

New Zealand (NZ) is a high risk country for multiple sclerosis (MS) with an overall age and sex standardised prevalence of 73.1 per 100,000 population. The age and sex standardised prevalence within the Māori population is substantially lower at 24.2 per 100,000 population. A latitudinal gradient exists with MS prevalence increasing threefold from the North (37°S) to the South (48°S) of NZ. Over 1600 (56.8%) persons with MS experience moderate to severe disability. Despite the high prevalence of MS and the significant degree of disability experienced by people with MS, the availability and prescribing guidelines for MS disease modifying treatments are more restrictive in NZ than in other developed nations.     

Genetic susceptibility to multiple sclerosis in Sardinians: an immunological study

Objectives - We studied the in vitro production of variably MS-related cytokines from Sardinian MS and healthy donors bearing the two "Sardinian" MS-associated HLA-DR alleles: DR3 and DR4 , with the purpose to evidentiate possible differences in their immune response. Materials and methods - ELISA were used for detection of cellular products by mitogen-activated peripheral blood mononuclear cells. Results - PHA-activated HLA-DR4+/DR3- mononuclear cells produce significantly higher amounts of TNF-α compared with the DR3 +/DR4- , In addition, homozygous HLA-DR3+ mononuclear cells from MS patients produce significantly lower amounts of IL-10 than those from homozygous HLA-DR3+ healthy donors. Conclusion - The abnormal production of detrimental or regulatory cytokines may account for the genetic susceptibility to MS in different HLA-subgroups of Sardinian MS patients.     

Epidemiology of multiple sclerosis in Sicily

From epidemiological data obtained over more than 20 years by surveys conducted in different parts of Sicily, it is evident that Sicily is a high-risk area for multiple sclerosis (MS). This is in sharp contrast with the gradient hypothesis. High frequencies have been found in different parts of the island having different geoclimatic features, but at least two cities (Monreale and Enna) had had a prolonged Norman domination. This is in agreement with the hypothesis that MS originated in Northern Europe and spread around the world throughout the raids of the northern peoples. The increase in frequency estimated by follow-up and incidence studies is well established and is only in part linked to the improvement in diagnostic techniques. Finally, it is noteworthy that in the islands of Malta, a few sea miles away from Sicily, the MS prevalence rates are in the range of 4–8 cases per 100 000 persons. This occurrence represents a natural model to investigate MS etiology through analytic studies and genetic analyses.     

The prevalence of multiple sclerosis in the world: an update

The systematic study of multiple sclerosis (MS) in populations, started in 1929 by Sydney Allison, now consists of over 400 publications dealing with the prevalence of MS throughout the world. However, any attempt to redefine the pattern of geographical differences in MS frequency remains as difficult as ever. The comparison of prevalence studies carried out in different areas and times is made difficult by the variability in surveyed population sizes, age structures, ethnic origins and composition, and the difficult quantification of numerators, especially regarding the recognition of benign and very early cases. Additionally, complete case ascertainment depends on access to medical care, local medical expertise, number of neurologists, accessibility and availability of new diagnostic procedures, the degree of public awareness about MS, and the investigators' zeal and resources. Critical examination of the more recent data on MS prevalence leads to some revisions of previously held concepts, the most interesting of which is the appreciation of the greater influence of genetic factors on disease acquisition. The rarity of MS among Samis, Turkmen, Uzbeks, Kazakhs, Kyrgyzis, native Siberians, North and South Amerindians, Chinese, Japanese, African blacks and New Zealand Maoris, as well as the high risk among Sardinians, Parsis and Palestinians, clearly indicate that the different susceptibilities of distinct racial and ethnic groups are an important determinant of the uneven geographic distribution of the disease. The updated distribution of MS in Europe, showing many exceptions to the previously described north-south gradient, requires more explanation than simply a prevalence-latitude relationship. Prevalence data imply that racial and ethnic differences are important in influencing the worldwide distribution of MS and that its geography must be interpreted in terms of the probable discontinuous distribution of genetic susceptibility alleles, which can however be modified by environment. Because the environmental and genetic determinants of geographic gradients are by no means mutually exclusive, the race versus place controversy is, to some extent, a useless and sterile debate.     

Multiple sclerosis epidemiology in Sardinia: evidence for a true increasing risk

OBJECTIVES: To update prevalence and incidence rates of MS among Sardinians. MATERIALS AND METHODS: The present work is a "spider" kind of population based survey, conducted over the interval 1968-97, on patients with MS (Poser criteria) living in the province of Sassari, Northern Sardinia (454,904 population). RESULTS: A crude total prevalence rate of 144.4 per 100,000, an onset-adjusted prevalence rate of 149.7 per 100,000 and an average annual incidence rate of 8.2 for the period 1993-7 were found. CONCLUSION: Repeated epidemiological assessments of MS in Sardinia over decades have shown that the island is at high risk for MS. The present work highlights that MS incidence in Sardinia has been increasing over time. Although a substantial and widely spread improvement in MS case ascertainment can be postulated as the reason for such observations, a comparison between our data and those recently reported from a more industrialized province in Northern Italy seems to prove an at least partially real increase in MS risk among Sardinians and favours the hypothesis of a MS "Sardinian focus" as related to its latitude.     

A prospective study of the incidence, prevalence and mortality of multiple sclerosis in Leeds

Objective: To establish the prospective incidence of multiple sclerosis and mortality rates of people with multiple sclerosis in Leeds Health Authority and an updated prevalence of multiple sclerosis on 31 October 1999. Methods A population based prevalence register established on 30 April 1996 was maintained by prospectively registering all new cases of multiple sclerosis, flagging all cases with the National Health Service Central Register for notification of deaths and by registering all new clinical events. General practitioners notified patients with multiple sclerosis moving into or out of the area. Results 136 incident cases were prospectively registered from 30 April 1996 living in Leeds Health Authority (with an estimated resident population of 728 840). 57 deaths were notified. 792 people with multiple sclerosis were identified living in Leeds on 31 October 1999. The mean annual incidence rate for the three-year period 1996–1998 was 6.1/10⁵ (95 % CI: 5.1–7.2). The sex ratio of incident cases was 2.3 to 1 women to men. On 31 October 1999 the prevalence of multiple sclerosis in the Leeds Health Authority was 108.7/10⁵ (95 % CI: 101.2–116.5). This compares with a prevalence of 97.3/10⁵ (95 % CI: 90.3 –104.7) on 30 April 1996. The prevalence of definite and probable multiple sclerosis was 93.3/10⁵ (95 % CI: 86.4–100.6) and of suspected multiple sclerosis was 15.4/10⁵ (95 % CI 12.7 –18.5). Crude annual mortality rates of people with multiple sclerosis for 1997 and 1998 were 1.9/10⁵ (95 % CI: 1.1 to 3.2) and 3.2/10⁵ (95 % CI: 2.0 to 4.7). Multiple sclerosis was noted as the underlying cause of death in 8 (14 %) cases. Conclusion The incidence of multiple sclerosis in the Leeds Health Authority is similar to that in the south of the United Kingdom. The difference in successive prevalence figures is less than that published in other serial studies. Multiple sclerosis was notified as the underlying cause of death in a minority of deaths in people with multiple sclerosis. Received: 5 December 2000, Received in revised form: 23 March 2001, Accepted: 10 July 2001     

The prevalence of migraine in multiple sclerosis (MS): A systematic review and meta-analysis

ObjectivesWe designed this systematic review to estimate pooled prevalence of migraine in patients with multiple sclerosis (MS).MethodsWe searched PubMed, Scopus, EMBASE, CINAHL, Web of Science, google scholar and gray literature including references from identified studies, conference abstracts which were published up to December 2019.The search strategy included the MeSH and text words as ((Disorder, Migraine OR Disorders, Migraine Disorder OR Migraine OR Migraines, OR Migraine Headache OR Migraine Headaches) AND (Multiple Sclerosis OR Sclerosis, Multiple) OR Sclerosis, Disseminated) OR Disseminated Sclerosis) OR MS (Multiple Sclerosis)) OR Multiple Sclerosis, Acute Fulminating).ResultsThe literature search found 2100 articles. After eliminating duplicates, 1500 articles remained. Eleven articles and twelve abstract conference papers were included for final analysis.A total of 11,372 MS cases and 2627 MS patients with migraine included in the analysis. The prevalence of migraine ranged from 2% to 67%.The pooled prevalence of migraine in included studies was 31% (95%CI: 22%–40%) (I² = 99.3%, p < 0.001). The pooled prevalence of migraine in different continents were significantly different (p < 0.001).The pooled prevalence was 24% in Asian countries, 43% in American countries, 25% in European countries and 43% in African countries.ConclusionThe results of this systematic review shows that the prevalence of migraine in MS patients is 31% while the prevalence differs significantly among residents of different continents.     

The influence of ethnicity on the characteristics of multiple sclerosis: A local population study between Persians and Arabs

Background

Based on previous studies, Iran is located in a low risk area in terms of multiple sclerosis (MS). The objective of this study was to determine and compare the incidence, prevalence and demographic characteristics of MS in two ethnic groups of Persian and Arab over the period spanning 2009 in the Khuzestan province, in the Southwest of Iran.

Methods

A cross-sectional case register study was conducted between January and August 2009. All cases in the region whom were referred to the MS society in the city of Ahwaz were participants in the study. The population data from the Iranian Bureau of Statistics were used to calculate the population at risk based on the 1996 and 2006 census data.

Results

A total of 696 patients were identified according to the McDonald criteria during the last 12 years of which 569 patients were Persian. In 2009 the total prevalence and incidence rates of MS were 16.28 and 2.20 per 100,000 individuals. Based on these values, the female to male ratios were 3.11. The Persians manifested more sensory signs and symptoms (40.2%) but motor deficits (19.1%) and cerebellar findings (18.2%) were seen as being more manifest in Arab individuals. The main difference was observed in the progressive types of MS in which 24.7% of the Arab patients showed progressive type symptoms as compared to 15.9% of the cases in the Persian population.

Conclusion

According to this study the authors conclude that the prevalence and incidence of MS were higher in Persians; however progressive forms of MS with motor and cerebellar signs are more frequent in the Arab ethnic group.     

Prevalence and incidence of multiple sclerosis in the city of Monreale, Italy

The prevalence and incidence of multiple sclerosis (MS) in the city of Monreale, southern Italy were ascertained 10 years after a preliminary study in the same area. The study was undertaken in a population of 26,256 people. The patients were classified according to Poser’s criteria. The prevalence of MS on 31 December 1991 was 72.4 per 100,000 population. The incidence of MS for the period 1981–1991 was 3.3/100,000 per year. The mean period between onset and diagnosis of MS was 4.9 years for those patients found during this survey and 9.2 years for those in the first study. This study shows an increase of MS prevalence in Monreale city and a high incidence. The findings parallel the reduction of the lag time between onset and diagnosis. Received: 25 March 1997 Received in revised form: 30 June 1997 Accepted: 10 July 1997     

Systematic review and meta-analysis of observational studies to understand the prevalence of restless legs syndrome in multiple sclerosis: an update

ObjectiveMultiple sclerosis (MS) is related to the demyelination of intracranial nerves at multiple sites, while restless legs syndrome (RLS) appears to be caused by dysfunction of the dopaminergic system. Since RLS prevalence is higher among MS patients than in the general population, we carried out an updated meta-analysis to understand whether the two diseases might be associated.MethodWeb of Science, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed databases were searched for observational and case-controlled studies of RLS prevalence in MS. Eligible studies were meta-analyzed using Stata 12.0.ResultsPooled RLS prevalence among MS patients of various ethnicities was 26%, and prevalence was lower in Asia (20%) than outside Asia (27%). Prevalence was higher among cross-sectional studies (30%) than among case–control studies (23%). RLS prevalence was higher among female than male MS patients (26% vs. 17%), and it was higher among MS patients than among healthy controls (OR 3.96, 95%CI 3.29–4.77, p < 0.001).ConclusionOur meta-analysis updates the most recent meta-analysis in 2013 and provides perhaps the first reliable pooled estimate of RLS prevalence in MS. The available evidence strongly suggests that RLS risk is higher among MS patients than healthy controls.     

Multiple sclerosis in Europe

At a symposium held in conjunction with the 13th World Congress of Neurology, epidemiological data were presented from 23 European countries. In addition to the confirmation of the well-known north-south gradient, new details emerged on the high-prevalence areas of the British Isles and Scandinavia and on high-prevalence areas in some of the eastern and Mediterranean countries requiring more intensive exploration and confirmation. It became evident that higher prevalences existed in some places in Southern Europe previously thought to be regions of very low frequency. Limitations in the evaluation and comparison of data presented were obvious in view of differences in concepts, techniques and the intensity of surveys carried out. There was general agreement that this first collaborative attempt to map the frequency of multiple sclerosis in Europe should be followed up by standardized procedures and more cooperation in epidemiological surveys.     

Immunogenetic heterogeneity of multiple sclerosis in Sardinia

Multiple sclerosis (MS) predisposition is thought to be influenced by a complex, yet unclear interaction of genetic and environmental factors. Studying ethnically selected populations may reduce genetic and environmental heterogeneities and help clarify the underlying mechanisms of MS susceptibility. Sardinians kept a homogeneous genetic structure and have among the highest MS frequency rates worldwide. Interestingly, MS in Sardinia is linked to otherwise rare HLA alleles. In this light, recent findings from epidemiological and immunogenetic studies of Sardinian MS are presented. Results confirm that, likely due to significant genetic differences at a microgeographic level, even in this homogeneous population MS is immunogenetically heterogeneous and tends to preferentially cluster in some more archaic areas of the island.     

Alpha B-crystallin is not a dominant peripheral T-cell autoantigen in multiple sclerosis amongst Sardinians

The heat shock protein alpha B-crystallin appears to be the dominantly recognized autoantigen in the early demyelinative process of multiple sclerosis (MS) in brain of patients. In Sardinia, MS is linked to human leucocyte antigen (HLA)-DR alleles that might influence the production of cytokines from peripheral lymphocytes. We tested the nature of peripheral anti-alpha B-crystallin-specific T-cell response in the context of predisposing HLA haplotypes both in MS patients and healthy controls. The alpha B-crystallin specific T-cell lines were generated by using the 'split-well' technique. The results indicate that the presence of short-term T-cell lines towards alpha B-crystallin is numerically comparable between the two groups and not restricted to MS-predisposing HLA-DR alleles. As for the T-cell characterization, CD4+ anti-alpha B-crystallin T cells secreting high levels of interferon-gamma are similarly identified in MS and healthy donors. In conclusion, the peripheral response towards the myelin antigen alpha B-crystallin is neither quantitatively nor qualitatively peculiar to MS, in contrast to the theoretical paradigm suggesting peripheral activation of myelin-reactive T cells to be the prerequisite for MS induction.     

Multiple sclerosis: postlinkage genetics

Because of the relative failure of linkage analysis in multiple sclerosis, despite the investigation of more than 700 affected relative pairs, we have applied four alternative strategies to identify genes that confer susceptibility to the disease. First, we have reported two clusters of MS patients from isolated populations where 19 and 13 patients, respectively, could be shown to have common ancestry tracing back several centuries. Three and five haplotypes, respectively, were shown to be shared by affected individuals, however, these haplotypes were extended and the statistical evidence modest. Second, we have recently reported the results of a two-stage candidate gene analysis of 66 selected genes, mostly of immune function. The IL-7 receptor alpha gene and LAG-3 both had three SNP markers associated with MS. Third, we recently identified the MHC class II transactivator gene in an animal model with inflammatory properties and later confirmed it to be of importance for MS, rheumatoid arthritis and acute myocardial infarction. Finally, in collaboration with the Serono Genetics Institute, we have completed a genome-wide screen with over 100,000 markers in three sets of 300 MS patients and 300 matched controls. Eighty genes showed evidence of importance in all three populations. These strategies appear to hold some promise of success where linkage analysis has proven less successful than anticipated.     

Multiple sclerosis: Symptomatic treatment

Reports of new therapeutic agents designed to suppress inflammatory processes in multiple sclerosis have excited much interest but, thus far, have had little influence on symptoms, disability and handicap in patients. The clinical application of recent advances in physical, pharmacological and surgical approaches to management will, at least in the medium-term future, therefore offer significantly greater opportunities for improving the quality of life of patients with multiple sclerosis. Here, symptomatic treatment of the whole range of difficulties encountered by patients with multiple sclerosis is reviewed in the context of the multidisciplinary strategy crucial to an optimal outcome.     

Multiple system atrophy masking multiple sclerosis

Multiple system atrophy (MSA) and multiple sclerosis (MS) are progressive neurological disorders with overlapping clinical signs and symptoms. However, due to the course of the disease and the age of onset both disorders are rarely differential diagnosis for each other. We here report the remarkable association of the two diseases in one patient. As MSA dominated the clinical presentation, diagnosis and therapy of MS were delayed. We discuss the clinical symptoms in our patient and highlight the features that allow to differentiate both diseases.     

Prevalence of multiple sclerosis in the province of Teruel, Spain

There have been few reports about the frequency of multiple sclerosis (MS) in Spain. We undertook a prevalence study in the province of Teruel, which is served by two hospitals as referral centres for a population of 143,680. We found a total of 46 patients who fulfilled Poser’s criteria for clinically definite or probable MS with a prevalence rate of 32/100,000 [95% confidence interval (CI): 22.8–41.3]. The prevalence rates for males and females were 23.5 (95% CI: 12.3– 34.7) and 40.6 (95% CI: 25.8–55.4) respectively. We found an incidence rate of 2.2/year per 100,000 in the last 5 years. The sex ratio (females/ males) was 1.7. The mean age on prevalence day was 40.6 years (range: 15–76). The clinical course was relapsing-remitting in 82% of patients, progressive in 9% and secondary progressive in the other 9%. The mean EDSS score was 3.73 (range: 1–8.5). Our results confirm the hypothesis that Spain is an area at high risk for MS. Received: 7 May 1996 Received in revised form: 17 September 1996 Accepted: 23 September 1996