Multiple sclerosis in the Republic of San Marino: a prevalence and incidence study

Systematic literature review and meta-analysis of the prevalence of secondary progressive multiple sclerosis in the USA, Europe, Canada, Australia, and Brazil

Background

Secondary progressive multiple sclerosis (SPMS) is a subtype of multiple sclerosis (MS), which is a chronic neurological disease, characterised by inflammation of the central nervous system. Most of MS patients eventually progress to SPMS. This study estimates the prevalence of SPMS in the United States of America, Europe, Canada, Australia, and Brazil.

Methods

A systematic literature search of the Medline and Embase databases was performed using the OVID™ SP platform to identify MS epidemiological studies published in English from database inception to September 22, 2020. Studies reporting the prevalence of MS and proportion of SPMS patients in the included population were selected. The pooled prevalence of SPMS was calculated based on the proportion of SPMS patients. The Loney quality assessment checklist was used for quality grading. A meta-analysis of the proportions was conducted in RStudio.

Results

A total of 4754 articles were retrieved, and prevalence was calculated from 97 relevant studies. Overall, 86 medium- and high-quality studies were included in the meta-analysis. Most studies were conducted in European countries (84 studies). The estimated pooled prevalence of SPMS was 22.42 (99% confidence interval: 18.30, 26.95)/100,000. The prevalence of SPMS was more in the North European countries, highest in Sweden and lowest in Brazil. A decline in SPMS prevalence was observed since the availability of oral disease-modifying therapies. We also observed a regional variation of higher SPMS prevalence in urban areas compared with rural areas.

Conclusion

High variability was observed in the estimated SPMS prevalence, and the quality of the studies conducted. The influence of latitude and other factors known to affect overall MS prevalence did not fully explain the wide range of inter-country and intra-country variability identified in the results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02820-0.

The epidemiology of multiple sclerosis in the entre Douro e Vouga region of northern Portugal: a multisource population-based study

BACKGROUND

The prevalence of Multiple Sclerosis (MS) has been increasing worldwide and the north-south gradient of prevalence may be disappearing in the Northern hemisphere. The few previous prevalence studies performed in Portugal have reported a lower prevalence than the average for Western Europe. The aim of this study is to estimate the prevalence of MS in the Entre Douro e Vouga region, in Northern Portugal.

METHODS

Multiple overlapping sources were used to ascertain all cases from the reference population: records from hospitals in the region and neighbouring regions; diagnostic databases of primary care physicians; and applications for disability benefits. The prevalence date was set at 1 January 2014. The reference population was 274,859 inhabitants. Patients' neurologists were contacted to retrieve clinical information and confirm the diagnosis based.

RESULTS

A total of 177 patients were identified after eliminating duplicates from different sources. The female to male ratio was 1.9 and the mean age at disease onset was 33.5 (standard deviation: 10.3). Clinically isolated syndrome accounted for 9.0% of patients, relapsing remitting for 58.8%, secondary progressive for 20.3% and primary progressive for 11.8%. The prevalence was estimated in 64.4 patients per 100,000 (95% confidence interval: 54.9;73.9).

CONCLUSIONS

In this study we report a higher point prevalence of MS than had been previously described in Portugal, but still far from the higher values recently reported in other Southern European countries.

Incidence of multiple sclerosis in Iran: a nationwide, population-based study

OBJECTIVES

The incidence of multiple sclerosis (MS) is not well known in Iran. This study was conducted to estimate the trends in annual MS incidence in Iran from March 21, 2010, to March 20, 2016.

STUDY DESIGN

Longitudinal study.

METHODS

In this longitudinal study, data for all MS patients fulfilling McDonald criteria were obtained from a national registry, coordinated by the Ministry of Health (MOH). In Iran, all MS patients are eligible to receive public care and treatment services based on their records in this registry, and thus nearly all MS patients are registered in this database. The annual incidence rates were calculated based on year of diagnosis and were standardized using the World Health Organization (2000-2025) population as a standard.

RESULTS

In this registry, 36,287 (8202 [22.6%] males and 28,085 [77.4%] females) confirmed MS cases were registered by the MOH between 2010 and 2016. The female-to-male ratio was 3.11. The mean age of patients was 31.6 ± 0.9 years at the time of diagnosis. It was 31.3 ± 0.8 and 32.3 ± 0.9 for females and males, respectively. Overall incidence rate was 6.7/100,000 population (95% confidence interval [CI]: 6.2-7.2); 10.5 and 3.0 in females and males, respectively. The age-adjusted incidence rates increased significantly from 4.4 (95% CI: 4.3-4.6) in 2010 to 5.8 (95% CI: 5.7-6.0) in 2016, with its peak at 6.5 (95% CI: 6.3-6.6) in 2014.

CONCLUSIONS

This study revealed that Iran is a high-risk area for MS disease and that MS incidence and female-to-male ratio are more or less comparable with the dominant patterns in developed countries. Also, this study showed that the incidence trend of MS in Iran is similar to regional and global observed patterns.

Epidemiology of inflammatory bowel disease in the Republic of San Marino: The "EPIMICI - San Marino" study

BACKGROUND

The burden of Crohn's disease (CD) and ulcerative colitis (UC) has never been estimated in the Republic of San Marino, the third smallest nation of the world.

AIMS

To assess the occurrence and clinical features of CD and UC in San Marino during the last 35 years.

METHODS

We retrospectively evaluated the prevalence, incidence, and main clinical aspects of CD and UC from 1980 to 2014, crossing data from various sources.

RESULTS

Prevalence rates (per 100,000) on December 31, were 241 for CD (263 in males and 220 in females) and 311 for UC (370 in males and 255 in females). The specific incidence of UC steadily increased from 4.6 (95% CI: 1.5-10.6) in 1980-1984 to 12.4 (95% CI: 7.6-19.1) in 2010-2014; CD incidence showed a higher proportional increase, from 1.8 (95% CI: 0.2-6.6) in 1980-1984 to 17.9 (95% CI: 12.0-25.7) in 2010-2014. The main clinical features of CD and UC (activity and location at diagnosis, extra-intestinal manifestations, disease progression overtime, therapies, and hospitalizations) were analyzed.

CONCLUSIONS

This study provides the first epidemiological report on CD and UC in San Marino, showing specific traits and overall higher prevalence and incidence rates than previously reported in neighbor Areas.

Geographic variations of multiple sclerosis in Iran: A population based study

BACKGROUND

The epidemiology of Multiple sclerosis (MS) has changed in recent decades. Considering that the incidence and geographical variations of MS is not well known in Iran. The present study was conducted to investigate the incidence of MS and its geographic variations in Iran.

METHODS

Data from a national registry, coordinated by the Ministry of Health (MOH), were collected for this study. In Iran, all MS patients are eligible to receive care and treatment services based on their records in this registry. Therefore, it seems that the related data are comprehensive with very high coverage, particularly in recent years. In this study, the annual incidence rates were calculated based on year of diagnosis of MS.

RESULTS

In this registry, 32,633 new cases were recorded between 2011 and 2016. After standardized for age, the mean annual incidence rate was 6.5 per 100,000 populations. It was 10.2 and 2.9 in women and men respectively. This incidence ranged from 1.7 to 12.8 in provincial level, with a higher intensity in the central part of the country.

CONCLUSION

It seems that the incidence rate of MS and its ratio in females and males are more or less comparable with the dominant patterns in developed countries, although its variation within the country is very considerable.

Estimated prevalence of multiple sclerosis in Italy in 2015

Italy is a high risk area for multiple sclerosis (MS) as confirmed by the numerous prevalence and incidence studies conducted in several regions/districts of the country. Nevertheless, there are no recent published epidemiological data, nor studies about the total prevalence of MS in Italy. Our aim was to update as of 2015 the prevalence rates of MS in different geographical areas using already published epidemiological studies, and to estimate the overall prevalence of the disease in Italy. We made a search in MEDLINE database of all published studies on epidemiology of MS in Italy. Then, we applied, to the already published prevalence data, the last published incidence and mortality rates to recalculate, as of 2015, the prevalence of MS. So, we calculated the mean prevalence rate from our extrapolations, and we applied it to the population in 2015 to estimate the number of MS patients in Italy. Our prevalence extrapolations ranged from 122 to 232 cases/100,000 in the mainland and Sicily, with an average of 176/100,000, and from 280 to 317 cases/100,000 in Sardinia with an average of 299/100,000. Applying these media to the Italian population in 2015, we obtained an estimate of more than 109,000 MS patients in Italy. Our estimates were higher than the latest published rates but consistent with the annual increase of prevalence due to incidence that exceeds mortality, with the increase of survival and, maybe, with the probable increase of incidence.

Onset-adjusted incidence of multiple sclerosis in the Girona province (Spain): Evidence of increasing risk in the south of Europe

BACKGROUND

Recent studies show an increasing incidence of multiple sclerosis (MS) in southern Europe. Although by its geographical location and genetic characteristics Spain is expected to be similar to other southern European regions, data on incidence are scarce. The aim of this study was to determine the onset-adjusted incidence of MS in the Girona province in Catalonia (Spain).

METHODS

A prospective incidence study pooling data from the population-based Catalonia MS Registry was performed. Incident cases were defined as patients who had the onset of symptoms compatible with a clinically isolated syndrome (CIS) suggestive of MS in 2009 and fulfilled McDonald-2005 criteria during follow-up. Age- and sex-specific incidence rates were obtained.

RESULTS

The Registry included 182 patients residing in Girona that presented a CIS from January 2009 to December 2013. Fifty one patients had the onset of symptoms in 2009, of whom 27 patients fulfilled the diagnostic criteria, giving an incidence of 3.6 per 100,000 (CI 95% 2.4-5.3) inhabitants; 4.3 (CI 95% 2.5-7.1) for women and 2.9 (CI 95% 1.4-5.2) for men. The age-adjusted incidence rate for the European population was 3.29 (CI 95% 3.2-3.3).

CONCLUSION

The incidence estimation derived in this study is consistent with recent epidemiological data of MS in southern Europe suggesting an increase in incidence in this region.

Prevalence of Multiple Sclerosis in Tuscany (Central Italy): A Study Based on Validated Administrative Data

BACKGROUND

Multiple Sclerosis (MS) epidemiology in Italy is mainly based on population-based prevalence studies. Administrative data are an additional source of information, when available, in prevalence studies of chronic diseases such as MS. The aim of our study is to update the prevalence rate of MS in Tuscany (central Italy) as at 2011 using a validated case-finding algorithm based on administrative data.

METHODS

The prevalence was calculated using an algorithm based on the following administrative data: hospital discharge records, drug-dispensing records, disease-specific exemptions from copayment to health care, home and residential long-term care and inhabitant registry. To test algorithm sensitivity, we used a true-positive reference cohort of MS patients from the Tuscan MS register. To test algorithm specificity, we used another cohort of individuals who were presumably not affected by MS.

RESULTS

As at December 31, 2011, we identified 6,890 cases (4,738 females and 2,152 males) with a prevalence of 187.9 per 100,000. The sensitivity of algorithm was 98% and the specificity was 99.99%.

CONCLUSIONS

We found a prevalence higher than the rates present in literature. Our algorithm, based on administrative data, can accurately identify MS patients; moreover, the resulting cohort is suitable to monitor disease care pathways.

Incidence of multiple sclerosis in Northern Lisbon, Portugal: 1998-2007

Background

There are few, recent, well assessed, multiple sclerosis (MS) incidence surveys on European populations. This study sought to measure MS incidence in a Northern Lisbon population and assess it using capture-recapture methods (CRMs).

Methods

Among the population residing in the Northern Lisbon Health Area, registered MS diagnoses were obtained from general practitioners in three primary-care districts covering a population of 196,300, and a neurology unit at the main referral hospital. Cases with onset during the periods 1978–1997 and 2008–2012 were excluded due to perceived poor access to image-supported neurological diagnosis and administrative changes in patient referral respectively. Age- and sex-specific incidences for the period 1998–2007 were calculated using McDonald diagnostic criteria, and CRMs were used to correct age-specific incidence rates. The corrected figures were also adjusted for age using the European Standard Population as reference.

Results

When applied to 62 MS patients with onset in the period 1998–2007, the rates per 100,000 population were as follows for both sexes: crude, 3.16; age-adjusted, 3.09 (95% CI 2.32 to 3.87); CRM-adjusted, 4.53 (95% CI 3.13 to 5.94); and age- and CRM-adjusted, 4.48 (3.54-5.41). In general, the rates were 3-fold higher among women than among men. Negative source dependency and CRM impact were highest at ages 35–44 years, where a 60% rise led to a peak incidence.

Conclusions

MS incidence in Northern Lisbon, Portugal, is moderately lower than that yielded by surveys on European populations. CRMs, which in this instance suggest undercounts, are a potentially useful tool for case-finding assessment but their application may introduce bias.

Sun exposure and multiple sclerosis risk in Norway and Italy: The EnvIMS study

Objectives:

The objective of this paper is to estimate the association between multiple sclerosis (MS) and measures of sun exposure in specific age periods in Norway and Italy.

Methods:

A total of 1660 MS patients and 3050 controls from Italy and Norway who participated in a multinational case-control study (EnvIMS) reported sun habits during childhood and adolescence.

Results:

A significant association between infrequent summer outdoor activity and increased MS risk was found in Norway and in Italy. The association was strongest between the ages of 16 and 18 years in Norway (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.30–2.59), and between birth and age 5 years in Italy (OR 1.56, 95% CI 1.16–2.10). In Italy a significant association was also found during winter (OR 1.42, 95% CI 1.03–1.97). Frequent sunscreen use between birth and the age of 6 years was associated with MS in Norway (OR 1.44, 95% CI 1.08–1.93) after adjusting for outdoor activity during the same period. Red hair (OR 1.67, 95% CI 1.06–2.63) and blonde hair (OR 1.36, 95% CI 1.09–1.70) were associated with MS after adjusting for outdoor activity and sunscreen use.

Conclusion:

Converging evidence from different measures underlines the beneficial effect of sun exposure on MS risk.

Increased incidence of multiple sclerosis in the Veneto region, Italy

BACKGROUND

To what extent the progressive increase in the incidence of multiple sclerosis (MS) observed in the province of Padova over the period 1970-1999 was an expression of a real increased risk of developing MS remained unclear.

OBJECTIVE

The objective of this paper is to update the epidemiological figures of MS and probe whether the risk of having MS has increased in the province of Padova during the decade 2000-2009.

METHODS

All patients born in Italy and having a diagnosis of MS or possible MS identified through analysis of all available sources of information were included in the study. The incidence and prevalence rates between 2000 and 2009 were obtained and compared with our previously published data.

RESULTS

On 31 December 2009, the overall prevalence was 139.5/100,000, 192.0 ± 9.5 for females and 83.9 ± 6.3 for males. During the decade 2000-2009, the overall incidence rate of MS was 5.5 ± 0.5, 7.4 ± 0.8 for females and 3.5 ± 0.6 for males. The onset-diagnosis delay, the female/male ratio and the mean age at onset did not significantly change compared to the prior period of observation.

CONCLUSION

Our findings support the hypothesis of a real increased risk of developing MS in the province of Padova. Moreover, the actual prevalence of 1.4/1000 makes our region a high-risk geographical area for MS. The role played by exogenous factors in determining susceptibility to MS needs to be thoroughly investigated.

Incidence and prevalence of multiple sclerosis in Europe: a systematic review

BACKGROUND

Multiple sclerosis (MS) is the most common cause of neurological disability in young adults worldwide and approximately half of those affected are in Europe. The assessment of differential incidence and prevalence across populations can reveal spatial, temporal and demographic patterns which are important for identifying genetic and environmental factors contributing to MS. However, study methodologies vary and the quality of the methods can influence the estimates. This study aimed to systematically review European studies of incidence and prevalence of MS and to provide a quantitative assessment of their methodological quality.

METHODS

A comprehensive literature search was performed to obtain all original population-based studies of MS incidence and prevalence in European populations conducted and published between January 1985 and January 2011. Only peer-reviewed full-text articles published in English or French were included. All abstracts were screened for eligibility and two trained reviewers abstracted the data and graded the quality of each study using a tool specifically designed for this study.

RESULTS

There were 123 studies that met the inclusion criteria. The study estimates were highly heterogeneous, even within regions or countries. Quality was generally higher in the more recent studies, which also tended to use current diagnostic criteria. Prevalence and incidence estimates tended to be higher in the more recent studies and were higher in the Nordic countries and in northern regions of the British Isles. With rare exceptions, prevalence and incidence estimates were higher in women with ratios as high as 3:1. Few studies examined ethnicity. Epidemiological data at the national level was uncommon and there were marked geographical disparities in available data, with large areas of Europe unrepresented and other regions well-represented in the literature. Only 37% of the studies provided standardized estimates.

CONCLUSIONS

Despite the breadth of the literature on the epidemiology of MS in Europe, inter-study comparisons are hampered by the lack of standardization. Further research should focus on regions not yet studied and the evaluation of ethnic differences in MS prevalence and incidence. National-level studies using current diagnostic criteria, validated case definitions and similar age- and sex-standardization would allow better geographical comparisons.

Infodemiology and infoveillance of multiple sclerosis in Italy

Multiple Sclerosis (MS) is a chronic debilitating disease of probable autoimmune inflammatory nature, whose aetiology is not fully understood, despite the many efforts and investigations. In this manuscript, we review the concept of “Multiple Sclerosis 2.0”, that is to say the Internet usage by MS patients, for seeking health and disease-related material for self-care and self-management purposes, and we introduce a Google Trends-based approach for monitoring MS-related Google queries and searches, called MS infodemiology and infoveillance. Google Trends has already proven to be reliable for infectious diseases monitoring, and here we extend its application and potentiality in the field of neurological disorders.

Incidence of multiple sclerosis among European Economic Area populations, 1985-2009: the framework for monitoring

Background

A debate surrounding multiple sclerosis epidemiology has centred on time-related incidence increases and the need of monitoring. The purpose of this study is to reassess multiple sclerosis incidence in the European Economic Area.

Methods

We conducted a systematic review of literature from 1965 onwards and integrated elements of original research, including requested or completed data by surveys authors and specific analyses.

Results

The review of 5323 documents yielded ten studies for age- and sex-specific analyses, and 21 studies for time-trend analysis of single data sets. After 1985, the incidence of multiple sclerosis ranged from 1.12 to 6.96 per 100,000 population, was higher in females, tripled with latitude, and doubled with study midpoint year. The north registered increasing trends from the 1960s and 1970s, with a historic drop in the Faroe Islands, and fairly stable data in the period 1980-2000; incidence rose in Italian and French populations in the period 1970-2000, in Evros (Greece) in the 1980s, and in the French West Indies in around 2000.

Conclusions

We conclude that the increase in multiple sclerosis incidence is only apparent, and that it is not specific to women. Monitoring of multiple sclerosis incidence might be appropriate for the European Economic Area.

Geomagnetic disturbances may be environmental risk factor for multiple sclerosis: an ecological study of 111 locations in 24 countries

BACKGROUND

We noticed that a hypothesis based on the effect of geomagnetic disturbances (GMD) has the ability to explain special features of multiple sclerosis (MS). Areas around geomagnetic 60 degree latitude (GM60L) experience the greatest amount of GMD. The easiest way to evaluate our hypothesis was to test the association of MS prevalence (MSP) with angular distance to geomagnetic 60 degree latitude (AMAG60) and compare it with the known association of MS with geographical latitude (GL). We did the same with angular distance to geographic 60 degree latitude (AGRAPH60) as a control.

METHODS

English written papers with MSP keywords, done in Europe (EUR), North America (NA) or Australasia (AUS) were retrieved from the PubMed. Geomagnetic coordinates were determined for each location and AMAG60 was calculated as absolute value of numerical difference between its geomagnetic latitude from GM60L. By an ecological study with using meta-regression analyses, the relationship of MSP with GL, AMAG60 and AGRAPH60 were evaluated separately. MSP data were weighted by square root of number of prevalent cases. Models were compared by their adjusted R square (AR2) and standard error of estimate (SEE).

RESULTS

111 MSP data were entered in the study. In each continent, AMAG60 had the best correlation with MSP, the largest AR2 (0.47, 0.42 and 0.84 for EUR, NA and AUS, respectively) and the least SEE. Merging both hemispheres data, AMAG60 explained 56% of MSP variations with the least SEE (R = 0.75, AR2 = 0.56, SEE = 57), while GL explained 17% (R = 0.41, AR2 = 0.17, SEE = 78.5) and AGRAPH60 explained 12% of that variations with the highest SEE (R = 0.35, AR2 = 0.12, SEE = 80.5).

CONCLUSIONS

Our results confirmed that AMAG60 is the best describer of MSP variations and has the strongest association with MSP distribution. They clarified that the well-known latitudinal gradient of MSP may be actually a gradient related to GM60L. Moreover, the location of GM60L can elucidate why MSP has parabolic and linear gradient in the north and south hemisphere, respectively. This preliminary evaluation supported that GMD can be the mysterious environmental risk factor for MS. We believe that this hypothesis deserves to be considered for further validation studies.

National estimate of multiple sclerosis incidence in France (2001–2007)

Background:

In France, the incidence of multiple sclerosis (MS) is not well known, and MS is one of the 30 long-term illnesses for which patients are covered for 100% of their health care costs.

Objective:

To estimate the incidence of MS in France and its geographic variations.

Methods:

We estimated the national rate for notification of MS to the main French health insurance system, and its confidence interval (CI), between November 2000 and October 2007, which covers 87% of the population. We analysed geographic variations using a Bayesian approach.

Results:

Between November 2000 and October 2007, among a covered population of 52,449,871, some 28,682 individuals were registered as having MS. After age standardization according to the European population, the notification rate for MS was 6.8 per 100,000 (6.7–6.9), 9.8 (9.7–10.0) in women and 3.7 (3.6–3.8) in men. When the under-notification rate (11.5% and 29%) was taken into account, the notification rate per 100,000 inhabitants was estimated between 7.6 and 8.8. The notification rate was higher in north-eastern France, and lower on the Atlantic coast and in the Alps as well as on both sides of the Rhône River.

Conclusions:

This study, conducted on a representative French population, provides for the first time national estimates of MS incidence between November 2000 and October 2007.

A 10-year serological follow-up of celiac disease in an Estonian population

BACKGROUND

Celiac disease (CD) is induced by wheat gluten and related prolamines. Its prevalence may be underestimated in many geographic regions and populations, and has recently increased in several countries. In 1998 and 1999, a random sample of Estonian schoolchildren was screened with IgA-type tissue transglutaminase antibodies (IgA-tTG) for CD. The results revealed a CD prevalence of 0.34%, which is lower compared with many other European countries.

OBJECTIVE

We rescreened the same population for CD using IgA-tTG after a 10-year interval.

MATERIALS AND METHODS

A total of 891 patients from the initial sample were rescreened using the IgA-tTG assay for a participation rate of 76.8% (median age, 24.3 years). As in the initial study, the IgA-tTG results were evaluated by ImmunoCAP EliA Celikey using an IgG-tTG and deamidated gliadin antibody assay for IgA-deficient cases.

RESULTS

No new cases of CD were found in this follow-up study. Of note, 75% of patients with initial IgA-tTG-positive results and biopsy-proven CD remained seropositive. One patient with a negative seroconversion at the time of rescreening followed a strict gluten-free diet during the follow-up years.

CONCLUSION

In a 10-year follow-up period, no new cases of CD were found in this Estonian population of school-children and young adults. Therefore, we presume no increase in CD during the last decade among this age group in Estonia. Additional studies are needed to determine whether similar results would be obtained in other age groups, because of differences in the CD prevalence between Estonian and other European populations.

A quantitative analysis of suspected environmental causes of MS

BACKGROUND

Multiple sclerosis (MS) is a disease with purported environmental causes. Consistent correlations have been found in various settings for latitude, smoking exposure, sunlight, and vitamin D deficiency. We analysed the contribution of various environmental factors to the risk of developing MS from a population perspective.

METHODS

We collated global data of MS prevalence from 54 studies over the previous ten years and calculated the degree of risk contributed by latitude, longitude, ultraviolet radiation (from NASA satellite data and formulae for available sunlight hours), population smoking rates (from WHO data), gender, study date, study demographics, and several socioeconomic factors. We report a very significant negative correlation between MS prevalence and available ultraviolet (UV) radiation.

RESULTS

The lack of available UV radiation outweighs other factors by at least 20 fold (p < 10⁻⁸) from single variate regression analysis. Multiple regression analysis revealed that latitude and longitude are also significant factors; smoking may also provide a very minimal role. The eight prevalence studies from Scandinavia produced prevalences that were lower than expected, given their global geospatial positioning.

CONCLUSIONS

The available ultraviolet radiation is a significant environmental factor, more so than all the other factors examined.

Increasing frequency of multiple sclerosis in Catania, Sicily: a 30-year survey

Background and Objective: The objective of this study was to determine the prevalence and incidence of multiple sclerosis (MS) and its temporal profiles from 1975 to 2005 in the city of Catania.

Methods: The incidence of MS from 1975 to 31 December 1999 had been previously investigated by the same group. The frequency of MS in the community of Catania from 1 January 2000 to 31 December 2004 was studied in a population of 313,110 inhabitants (2001 census). All patients who satisfied Poser’s criteria were considered as prevalent and incident cases.

Results: Three hundred and ninety-eight patients with MS who had experienced the clinical onset of the disease before 31 December 2004 were found in a population of 313,110 inhabitants. The prevalence rate was 127.1/100,000 [95% confidence interval (CI) 115.1–140.4]. From 2000 to 2004, 108 patients with MS had clinical onset of the disease . The mean annual incidence was 7.0/100,000 (95% CI 5.7–13.7) and was higher in women (8.4/100,000; 95% CI 6.4–10.5) than in men (5.3/100,000; 95% CI 3.7–7.2). The mean length of time between the date of clinical onset and the date of the diagnosis was 1.4 ± 1.7 years. During the last 30 years the incidence of MS in this population increased from 1.3/100,000 during the first quinquennium (1975–9) to 7.0/100,000 during 2000–4.

Conclusions: Incidence rates have further increased in this population, suggesting that the risk of MS is still increasing.

Epidemiology of multiple sclerosis in Europe: a review

Multiple sclerosis (MS) is a progressive demyelinating and degenerative disease of the CNS with symptoms dependent on the type of the disease and the site of lesions. During the progression of the disease, symptoms become more permanent and progressive disability ensues. MS is a disease characterized by wide variations between patients, thus making categorization difficult. The aim of the current study was to review the existing epidemiological data of MS in Europe published during the last decade (2000-2009), using PubMed. Findings revealed an increasing incidence of MS during the last decade. Recent data indicate that latitude does not play a key role in determining the onset of the disease. MS has a significant impact on the quality of life for most patients over many years. The disease is twice as common in women than in men, and is at its peak in the most economically productive years of life. Pregnancy, postpartum status and vaccines may influence the onset and the course of the disease. Only one of the reviewed papers provides a view of progression from onset to death.

The changing demographic pattern of multiple sclerosis epidemiology

The uneven distribution of multiple sclerosis (MS) across populations can be attributed to differences in genes and the environment and their interaction. Prevalence and incidence surveys could be affected by inaccuracy of diagnosis and ascertainment, and prevalence also depends on survival. These sources of error might play a part in the geographical and temporal variations. Our literature search and meta-regression analyses indicated an almost universal increase in prevalence and incidence of MS over time; they challenge the well accepted theory of a latitudinal gradient of incidence of MS in Europe and North America, while this gradient is still apparent for Australia and New Zealand; and suggest a general, although not ubiquitous, increase in incidence of MS in females. The latter observation should prompt epidemiological studies to focus on changes in lifestyle in females. New insights into gene-environment and gene-gene interactions complicate interpretations of demographic epidemiology and have made obsolete the idea of simple causative associations between genes or the environment and MS.

Recent insights in the epidemiology of autoimmune diseases: improved prevalence estimates and understanding of clustering of diseases

Previous studies have estimated a prevalence of a broad grouping of autoimmune diseases of 3.2%, based on literature review of studies published between 1965 and 1995, and 5.3%, based on national hospitalization registry data in Denmark. We examine more recent studies pertaining to the prevalence of 29 autoimmune diseases, and use these data to correct for the underascertainment of some diseases in the hospitalization registry data. This analysis results in an estimated prevalence of 7.6-9.4%, depending on the size of the correction factor used. The rates for most diseases for which data are available from many geographic regions span overlapping ranges. We also review studies of the co-occurrence of diseases within individuals and within families, focusing on specific pairs of diseases to better distinguish patterns that may result in insights pertaining to shared etiological pathways. Overall, data support a tendency for autoimmune diseases to co-occur at greater than expected rates within proband patients and their families, but this does not appear to be a uniform phenomenon across all diseases. Multiple sclerosis and rheumatoid arthritis is one disease pair that appears to have a decreased chance of coexistence.

High prevalence of multiple sclerosis in the Swedish county of Värmland

Previous epidemiological studies have indicated that the county of Värmland in western Sweden may be a high-risk zone for multiple sclerosis (MS). The objective of this study was to determine the prevalence in the area. Hospital and general practice medical files were scrutinized. The diagnostic criteria of Poser were used, with 31 December 2002 as prevalence day. The prevalence was 170.07 per 100,000 inhabitants. The average annual incidence was 6.39 to 6.46 per 100,000 (1991—1995, 1996—2000). Multiple sclerosis was 2.3 times more common among women than men. There was a variation in prevalence among the 16 municipalities, however it was not statistically significant. The rates seemed highest in the southwestern part of the county, roughly similar in location to findings some 70 years earlier. When the prevalence ratios by geographical units for the county in 1933 were applied to the current prevalence, the distribution from these estimated cases differed from homogeneity with very high significance (p < 0.00001 ). In conclusion, this study supports previous reports indicating that Värmland continues to be a high-risk zone for MS and shares in the diffusion of the disease at the county level which we had presented for the country as a whole.