Multiple sclerosis in Gijon health district, Asturias, northern Spain

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

INTRODUCTION

Greater understanding of the prevalence and incidence of multiple sclerosis in Spain and their temporal trends is necessary to improve the allocation of healthcare resources and to study aetiological factors.

METHODS

We performed a systematic search of the MedLine database and reviewed the reference lists of the articles gathered. We collected studies reporting prevalence or incidence rates of multiple sclerosis in any geographical location in Spain, with no time limits. In 70% of cases, data were extracted by 2 researchers (FGL and EAC); any discrepancies were resolved by consensus.

RESULTS

We identified 51 prevalence and 33 incidence studies published between 1968 and 2018. In the adjusted analysis, the number of prevalent cases per 100 000 population increased by 26.6 (95% confidence interval [CI], 21.5-31.8) every 10 years. After adjusting for year and latitude, the number of incident cases per 100 000 population increased by 1.34 (95% CI, 0.98-1.69) every 10 years. We observed a trend toward higher prevalence and incidence rates at higher latitudes.

CONCLUSIONS

The prevalence of multiple sclerosis in Spain has increased in recent decades, although case ascertainment appears to be incomplete in many studies. Incidence rates have also increased, but this may be due to recent improvements in the detection of new cases.

Immunosenescence: the role of age in multiple sclerosis

INTRODUCTION

The number of elderly people with multiple sclerosis (MS) has increased in line with population ageing. As the immune system presents profound changes over an individual's lifetime, it is important to understand the differences between these patients and younger patients.

DEVELOPMENT

Immunosenescence, defined as age-related alterations naturally occurring in the immune system, particularly influences tolerance, response, and adverse effects of disease-modifying treatments for MS. Thymic involution is the most noteworthy characteristic of this phenomenon. This process leads to a reduction in the number of virgin T cells. Other effects include an inverted CD4+/CD8+ cell ratio, severe alterations in NK cell functioning, and reduced tissue repair capacity in the brain.

CONCLUSIONS

The number of older people with MS is increasing due to population ageing, advances in disease-modifying treatments, and improved health and social care of these patients. Ageing of the immune system increases the risk of infections, tumours, and autoimmune diseases in elderly individuals. Furthermore, neurodegeneration is accelerated in patients with MS due to the nervous system's loss of remyelination capacity. Understanding of the changes affecting the immune system in the elderly population is essential to improving the care provided to this ever-growing patient group.

Temporal trends in the incidence and prevalence of Multiple Sclerosis in the Northwest of Spain

BACKGROUND

During the last decades, the frequency of multiple sclerosis (MS) is increasing worldwide. Nevertheless, the higher sensibility of the new diagnostic criteria obscures the comparison between studies performed in different decades.

METHODS

The evolution of the frequency of MS in Santiago de Compostela (North-West of Spain) between 2003 and 2015 was analyzed using Poisson regression. The diagnosis was confirmed according to Poser criteria. Several sources were consulted for case ascertainment: databases from the MS Unit, the Infusion Center, and the Departments of Neurology, Pharmacy, Pediatric Neurology and Codification of the public Hospital of Santiago, private hospitals, neurologists with private activity, general practitioners, and associations of patients.

RESULTS

In 12 years, the prevalence increased from 68 to 143 cases/100,000 inhabitants, from 83 to 176 in females; and from 49 to 106 in males (p <0.0001, 0.0001, and 0.0002 respectively). The incidence rise was not significant (from 5 to 8 cases/ 100,000 inhabitants/ year (p=0.4243). The mean age of the population growth 5.7 years (p=0.008). The changes in female: male ratio (12.9%), in the age at the first symptom (2.2 years), and the diagnosis delay (0.12 years) did not achieve significance (p=0.7750, 0.1606, 0.8581).

CONCLUSION

The prevalence of MS doubled in 12 years whilst the difference in incidence was lower and not significant. The disproportion in the growth of both parameters, as well as the higher mean age in the last study, suggest a longer survival of patients with MS.

Immunosenescence: the role of age in multiple sclerosis

INTRODUCTION

The number of elderly people with multiple sclerosis (MS) has increased in line with population ageing. As the immune system presents profound changes over an individual's lifetime, it is important to understand the differences between these patients and younger patients.

DEVELOPMENT

Immunosenescence, defined as age-related alterations naturally occurring in the immune system, particularly influences tolerance, response, and adverse effects of disease-modifying treatments for MS. Thymic involution is the most noteworthy characteristic of this phenomenon. This process leads to a reduction in the number of virgin T cells. Other effects include an inverted CD4 + /CD8 + cell ratio, severe alterations in NK cell functioning, and reduced tissue repair capacity in the brain.

CONCLUSIONS

The number of older people with MS is increasing due to population ageing, advances in disease-modifying treatments, and improved health and social care of these patients. Ageing of the immune system increases the risk of infections, tumours, and autoimmune diseases in elderly individuals. Furthermore, neurodegeneration is accelerated in patients with MS due to the nervous system's loss of remyelination capacity. Understanding of the changes affecting the immune system in the elderly population is essential to improving the care provided to this ever-growing patient group.

Prevalence of multiple sclerosis in Santiago de Compostela (Galicia, Spain)

Introduction

Multiple sclerosis (MS) is the most common central nervous system disease in young adults, and one of the leading causes of disability in this age group.

Objectives

To establish the prevalence and incidence of MS in Santiago de Compostela (Spain).

Material and methods

We performed a prospective, case-finding study on >90188 inhabitants, from 1 January 1998 to 15 September 2003, selected as day of prevalence. Sources of information were the University Clinical Hospital of Santiago, the hospitals and private clinics of the city, rehabilitators, pediatricians, ophthalmologists, psychiatrists, neurosurgeons, specialists in internal medicine, primary care physicians, association of patients of MS, social services and nongovernmental and religious associations. Informative days were programmed for the susceptible population, and campaigns were carried out in the media. All patients with Poser diagnostic criteria for MS, on the census of Santiago de Compostela as of 15 September 2003, were included in the study.

Results

On the day of prevalence, 71 patients with MS were registered on the census of Santiago de Compostela, therefore, the prevalence was 79 cases per 100000 inhabitants. The incidence of the disease in the study period was 5.3 cases per 100000 inhabitants and year.

Conclusions

The prevalence and incidence rates of MS found in Santiago de Compostela are the highest reported, to date, in Spain. Multiple Sclerosis 2007; 13: 262–264. http://msj.sagepub.com

A systematic approach to analyse health-related quality of life in multiple sclerosis: the GEDMA study

Objective: To describe a holistic and comprehensive approach to the assessment of sufferer’s perceptio ns of health-related quality of life (HRQ oL) in a cohort of multiple sclerosis (MS) patients. Methods: The G EDMA (Grupo de Enfermedades Desmielinizantes de Madrid, in Spanish) study is an ongoing longitudinal survey using quantitative and qualitative methodologies. The baseline cohort consisted of a large sample of MS patients recruited from 13 hospitals in Madrid, Spain. Using a standardized protocol we collected data concerning the sociodemographic and health status characteristics of patients, as well as implementing a modified Spanish version of the Functio nal A ssessment of Multiple Sclerosis quality of life instrument. Primary caregivers were interviewed using a specific protocol combined with the Zarit Burden Interview. Results: The index cohort comprised 371 MS patients (68.7% female) of mean age 38.9 ± 0.9 years. A ge, sex and clinical form distribution were similar to other MS population-based surveys. There were 258 (69.5%) relapsing-remitting (RR) MS patients and 113 (30.5%) progressive MS patients. More than one-third of the married patients with progressive MS and almost a quarter of the RRMS patients separated or divorced following a diagnosis of MS; 71.3% of the progressive MS patients as well as 65.8% of the RRMS patients were unemployed as a consequence of the disease. Q ualitative analysis showed that friendship and family relationships and occupational status were the most significant dimensions influenced by MS. O n the other hand, the speech analysis of primary caregivers showed that emotional burden was related to patients’ physical disability. Furthermore, primary caregivers described the influence of MS on their own occupatio nal status, their nonacceptance of the disease, a perceptio n of a lack of support by other members of the family as well as a ‘selfish and intransigent’ attitude of the patients themselves. Conclusions: The analysis of the G EDMA cohort provides valuable information that helps clarify the impact of MS on patients’ HRQ oL.

Long-term epidemiology of multiple sclerosis in the Northern Seville District

OBJECTIVES

Comprehensive epidemiologic data for multiple sclerosis (MS) in Spain are limited. The aim of this study was to collect epidemiologic data on MS in the Northern Seville District of Spain.

MATERIALS AND METHODS

This longitudinal study identified possible MS cases every year from nine centres between 1 January 1991 and 31 December 2011. Patients with a confirmed diagnosis of MS were included. MS data prior to enrolment were collected retrospectively from clinical records and prospectively during quarterly follow-up clinic visits. Variables included age at onset, age at diagnosis, treatment, follow-up duration, number of visits, number of relapses, change in the number of relapses over time and Expanded Disability Status Scale score. The incidence and prevalence of MS rate were calculated.

RESULTS

Overall, 156 patients with MS were identified (111 females; mean follow-up 7.5 years). Most patients had relapsing-remitting MS (73.7%); primary progressive disease was less frequent than secondary disease (10.9% vs 15.4%). The yearly incidence of MS was 4.6 per 100,000, and the prevalence at 31 December 2011 was 90.2 per 100,000.

CONCLUSIONS

The annual MS incidence rate in this southern region of Spain was higher than previously reported rates in Spanish studies.

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.

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.

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.

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.

The epidemiology of multiple sclerosis in Europe

Multiple sclerosis (MS) is a chronic and potentially highly disabling disorder with considerable social impact and economic consequences. It is the major cause of non-traumatic disability in young adults. The social costs associated with MS are high because of its long duration, the early loss of productivity, the need for assistance in activities of daily living and the use of immunomodulatory treatments and multidisciplinary health care. Available MS epidemiological estimates are aimed at providing a measure of the disease burden in Europe. The total estimated prevalence rate of MS for the past three decades is 83 per 100,000 with higher rates in northern countries and a female:male ratio around 2.0. Prevalence rates are higher for women for all countries considered. The highest prevalence rates have been estimated for the age group 35-64 years for both sexes and for all countries. The estimated European mean annual MS incidence rate is 4.3 cases per 100,000. The mean distribution by disease course and by disability is also reported. Despite the wealth of epidemiological data on MS, comparing epidemiological indices among European countries is a hard task and often leads only to approximate estimates. This represents a major methodological concern when evaluating the MS burden in Europe and when implementing specific cost-of-illness studies.

The prevalence of multiple sclerosis in the District of Santarém, Portugal

The prevalence of multiple sclerosis (MS) in Portugal is still unknown. Recent studies conducted in southern European countries showed higher than expected rates of MS prevalence. In an attempt to evaluate the MS prevalence in Santarém--a district with 62621 inhabitants (1991 census) located in the centre of Portugal--we have conducted a population survey in this district for five years. The crude prevalence rate found was 46.3/100,000. This figure is not different from findings recently reported in studies conducted at similar latitudes in neighbour southern European countries. This was the first population survey conducted in Portugal, and it is the first accurate contribution to the knowledge of the MS prevalence in this country.

[Prevalence of neuropathic pain in Spain: clinical, working and health care implications]

A narrative systematic medical literature review on prevalence of neuropathic pain (NP) in Spain from 1990 to 2004 was conducted. The average number of publications was 3 per year. Prevalence data varied depending on studied population, definition of pain/pathology and time of pain evolution. The most commonly studied pathologies included: mononeuropathies and polyneuropathies: 42%, multiple sclerosis: 35% and entrapment neuropathies: 16%. Some episodes of NP were left untreated. One third of patients with back pain receiving analgesic treatment still had high intensity pain. Future studies on the prevalence of NP should use work definitions and criteria reached by consensus. An awareness of the clinical presentation of NP and an appropriate and early treatment could minimize its clinical, working and health care implications. NP is a diverse and highly prevalent condition in Spain. Efforts should be conducted towards the achievement of diagnostic criteria consensus and higher rates of analgesic success.

Mortality of Multiple Sclerosis in Spain: Demonstration of a North-South Gradient

OBJECTIVE

To analyse the geographical distribution of multiple sclerosis in Spain from 1975 to 1998.

METHODS

Age-adjusted mortality rates by province were obtained by the indirect method using the whole Spanish population as the reference. Then, standardised mortality ratios (SMRs) and their 95% confidence intervals were estimated.

RESULTS

For both men and women, provinces with SMRs higher than the mean tended to be in the northern third of Spain, whilst those with SMRs lower than the mean were mostly located in the southern half. A linear regression analysis showed a significant positive association between mortality and latitude.

CONCLUSION

A north-south gradient in age-adjusted multiple sclerosis mortality exists in Spain.

Prevalence and incidence of multiple sclerosis in Las Palmas, Canary Islands, Spain

OBJECTIVES

To determine the prevalence and incidence of multiple sclerosis (MS) in the city of Las Palmas (Canary Islands, Spain), geographically belonging to north-western Africa, but with European ancestry.

METHODS

This population-based survey was conducted for a period of 5 years (1998-2002) in a Sanitary District of Las Palmas city (28 degrees 20' N), with a population of 82,623 inhabitants. Multiple sources were periodically investigated for case ascertainment. Patients with definite and probable MS were included.

RESULTS

Sixty-four patients with MS were identified on prevalence day, December 31, 2002. According to Poser's criteria the crude prevalence rate was 77.5 per 100,000 (95% CI: 59.7-98.9). This rate decreased to 73.8 (95% CI: 56.5-94.8) according to McDonald's criteria. Age-adjusted rates for the world and European standard populations were 61.6 (95% CI: 47.1-78.9) and 70.6 (95% CI: 55-89), respectively. Prevalence was higher for women aged 25-44 years. In 17 patients onset of MS occurred within the study period. Average annual incidence was 4.1 per 100,000 (95% CI: 2.4-6.6).

CONCLUSIONS

The prevalence and incidence rates in Las Palmas city are close to those reported from Continental Spain and other countries of southern Europe with similar social and ethnic background. These results highlight the role of racial-ethnic factors in the genesis of MS.

Informal caregiving in multiple sclerosis patients: data from the Madrid Demyelinating Disease Group study

PURPOSE

To describe the profile of Multiple Sclerosis (MS) patient caregivers and assess their caregiving burden.

METHODS

A total of 91 MS patients, recruited from a Spanish longitudinal survey, and their corresponding caregivers were studied. Caregivers were administered a questionnaire that collected social and demographic data, and a generic caregiver burden interview (the Zarit scale). Furthermore, MS patients were administered a specific health-related quality of life (HRQoL) instrument (the modified Spanish version of the Functional Assessment of Multiple Sclerosis).

RESULTS

24.5% of the sample required caregivers to perform activities of daily life. Caregiver profile was as follows: 67% female; mean age, 51.5 +/- 14.1 years; and mean daily time devoted to care, 11.5 +/- 8.2 h. Most caregivers had some type of support, 67% informal and 31.9% formal. The amount of time spent in caring for relatives was the main item determining the burden of MS-patient caregivers. Moreover, MS patient's HRQoL showed a moderate inverse correlation with caregiver burden.

CONCLUSIONS

In contrast to previous studies, most Spanish MS-patient caregivers are female, and there is a considerable percentage of parent caregivers. A greater degree of formal support and an improvement in MS patients' HRQoL may serve to reduce caregiver burden.

The HLA locus and multiple sclerosis in Spain. Role in disease susceptibility, clinical course and response to interferon-beta

The HLA-DR2 haplotype (DRB1*1501, DQB1*0602) on chromosome 6p21 has consistently demonstrated both association and linkage with multiple sclerosis (MS) in case-control and family studies, particularly in Caucasians of Northern European descent. However, the role of a gene within this region in determining clinical features or response to immunotherapy remains largely unknown. A new familial MS data set from the Mediterranean Spanish Basin was collected according to rigorous ascertainment criteria. We confirm, primarily in the cohort originating from Continental Spain, that similar to other high-risk groups, there was a significant association with HLA-DR2. No other DR or DQ alleles were found to be associated with disease susceptibility nor were alleles at the class I A and B loci. Overall, the effect of HLA appears to be less substantial than that observed in a reference US population with a higher disease incidence. No effect of the HLA-DR2 haplotype on age of onset, initial clinical symptoms and disease course was observed. Similarly, no difference in the distribution of responders and nonresponders to interferon-beta (IFNB) therapy, as defined by primary and secondary end points, was observed when individuals were stratified according to HLA-DR2 status.

Multiple sclerosis in Malta in 1999: an update

OBJECTIVES

To ascertain the prevalence of multiple sclerosis (MS) in the islands of Malta and compare it with a previous study undertaken 21 years earlier, when a remarkably low prevalence was found.

METHOD

Deaths with MS on the death certificate since the last study were reviewed. Sources of information about new patients were the Hospital Activity Analysis scheme, the MS Society of Malta, the records of the state hospitals, long stay private hospitals and nursing homes, lists provided by the state pharmacies, and magnetic resonance imaging, cerebrospinal fluid, and evoked response studies. Prevalence day was 1 January 1999. The Poser classification was used.

RESULTS

Since 1978, 17 patients had died with a verified diagnosis of MS on the death certificate. They included all 10 deaths with MS from the original study and two immigrants. Fifty patients had clinically definite MS (CDMS) and 13 clinically probable MS (CPMS). The prevalence of CDMS was 13.2/100 000 (male 11.2, female 15.2). The prevalence of CDMS and CPMS combined was 16.7/100,000 (male 13.3, female 19.9). The annual incidence was 0.7/100,000. Twelve patients were found with CDMS among the 7213 immigrants resident in Malta (166/100,000). The expected rate was 1/100,000, determined at Maltese born rates. There were major changes in the population distribution during the 21 years between the two studies, with a big increase in the age groups with a high risk of MS. There is a longer expectation of life and the diagnosis in now made earlier.

CONCLUSION

Malta still has a low MS prevalence. In comparison with Sicily and other Mediterranean countries of Europe it offers an opportunity to ascertain the genetic and environmental factors responsible for the disease.

First hospital-admission rate as an epidemiological indicator for patients with multiple sclerosis in Stockholm, 1984-1993

OBJECTIVES

To evaluate the first hospital-admission patients with multiple sclerosis (MS) in the population.

MATERIAL AND METHODS

By using the data from hospital discharge registry of MS diagnosis in Stockholm during 1984-1993, we calculated rates of first hospital-admission patients with MS in the population and evaluated the temporal trend of the rates during the study period.

RESULTS

There were 719 first hospital-admission patients with MS corresponding to 1556 admissions. The mean age at the first admission was nearly the same for male patients (44.3 years, SD: 12.9) and for female patients (44.6 years, SD: 13.7). The mean annual rate of first hospital-admission patients with MS was 4.46 per 100,000 person-years. The sex rate ratio of first hospital-admission patients with MS between females and males was 2.19:1.

CONCLUSION

The first hospital-admission rate of MS could be used as an epidemiological indicator which is useful in planning of hospital service for MS patients.

Multiple sclerosis in Móstoles, central Spain

OBJECTIVES

Until relatively recently southern Europe was regarded as having a medium to low multiple sclerosis prevalence, of about 20 or less per 100,000. However, recent studies in Sardinia, Sicily, continental Italy, Cyprus and Spain have yielded higher MS prevalence rates, between 32 and 102.6 per 100,000. We present the results of a prevalence study of MS in the municipality of M6stoles, central Spain.

MATERIAL AND METHODS

To ascertain the prevalence of multiple sclerosis in M6stoles (195,979 inhabitants), an intensive study was undertaken using several sources of information. We used the Poser criteria in diagnosis.

RESULTS

There were 85 patients (53 women and 32 men) classified as definite or probable, prevalence 43.4/100,000 (95% CI, 34.7 to 53.7). The incidence rate was 3.8/100,000/year (95% CI, 2.7 to 5.3) in the last 5 years. Mean age on prevalence day was 38.8+/-10.9 years. Mean age at onset was 31.7+/-9.3 years. Mean interval between initial symptoms and diagnosis was 1.7 years. Mean duration of disease was 7.6+/-6.1 years. Overall, 70.6% had a relapsing-remitting course, 18.8% had a primary progressive and 10.5% had a secondary progressive. Mean EDSS score was 2.7+/-1.9.

CONCLUSION

The M6stoles study confirms the conclusions of previous smaller population studies that Spain is a moderately high or medium MS risk zone.

HLA associations with multiple sclerosis in the Canary Islands

The study of small island populations has proved informative with respect to the epidemiology and genetics of many complex traits including multiple sclerosis. The class II major histocompatibility antigen DR15 is associated with multiple sclerosis in all groups except Sardinians, where the primary association is with DR4. We compared HLA-DR and -DQ allele frequencies in a representative sample of patients with multiple sclerosis from the Canary Islands with appropriate controls. There was a significant association with DR15 (patients 21/53: 40%: controls 11/55; 20%: chi2=4.09; pc=0.04; relative risk [RR]=1.98). DRB1*1501-DRB5*0101 was present in 17/53 (32%) patients in whom sub-types could be identified compared with 6/55 (11%) controls (chi2=7.21; pc=< 0.01; RR=2.94). All DR15 positive controls carried the DQA1*0102, DQB1*0602 haplotype whereas this was only present in 26/30 patients, suggesting that the primary association is with HLA-DR and not -DQ. We also found a significant increase in HLA-DR4 (16/53 [30%] in patients compared with 7/55 [13%] in controls; pc=0.05). This study contributes a new point on the immunogenetic map of multiple sclerosis in Europe, confirming the primary DR15 association with multiple sclerosis in a previously unstudied population but again highlighting the importance of DR4 in Mediterranean peoples.