Epidemiology of multiple sclerosis in Italy and in southern Europe

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.

Incidence and Prevalence of Multiple Sclerosis in Newfoundland and Labrador

Background:

The incidence and prevalence of multiple sclerosis (MS) in Newfoundland and Labrador (NL) had been reported in 1984 and was considered to be relatively low at that time. This study revisits the incidence and prevalence of MS in NL for the year 2001.

Methods:

Case searches through patient files of neurologists in NL were conducted. A complete list of patients billed for MS in NL between 1996 and 2003 was obtained and all cases were confirmed via chart review.

Results:

There were 493 living MS patients yielding a prevalence of 94.4/100,000 which is significantly higher than previously reported. Of the living patients, 330 had relapsing remitting (RRMS), 94 had secondary progressive, 66 had primary progressive (PPMS) and three had unspecified MS. The total female to male ratio was 2.7:1. There was no difference between the female to male ratios for RRMS vs PPMS. Patients with PPMS had a later onset compared to RRMS (p<0.00001). Yearly incidences were relatively constant from 1994 to 2001 (5.6/100,000). Significant delays between first symptoms and final diagnosis were common and the delay time has not changed over the past 15 years. A prevalence of 88.9/100,000 was estimated from survival and incidence trends and was not significantly different than the measured prevalence (p=0.38).

Conclusion:

The increase in incidence and prevalence are accounted for through both better access to diagnostic facilities and more practicing neurologists. The revised prevalence and incidence are more in keeping with recently reported values throughout Canada.

Conclusion:

L’augmentation de l’incidence et de la prÉvalence se justifient par une plus grande accessibilitÉ aux moyens diagnostiques et par la prÉsence d’un plus grand nombre de neurologues. La prÉvalence et l’incidence que nous rapportons sont plus conformes à celles rapportÉes rÉcemment à travers le Canada.

The prevalence of multiple sclerosis in central Italy

Background: The prevalence of multiple sclerosis varies considerably throughout the world.

Objective: To better define the prevalence of MS in central Italy.

Methods: This is a population-based study conducted in the province of Frosinone, which is situated in the Lazio region, central Italy. The selected prevalence day was 1 January 2007. A total of 467 patients, with a definite diagnosis of multiple sclerosis, were considered for crude, age- and sex-specific prevalence estimation.

Results: The overall crude prevalence rate was 95.0 cases per 100,000 (95% confidence interval (CI) 86.6—104.0). A significantly higher prevalence rate was recorded in females (134.9, 95% CI 121.0—150.1) than in males (53.3, 95% CI 44.4—63.3) ( p = 0.001). Age-specific prevalence peaked in the 25—34 year, 35—44 year and 45—54 year age groups; moreover, it was found to increase up to the 35—44 year age group in males and the 45—54 year age group in females, decreasing thereafter. The female to male ratio was 2.6.

Conclusions: The results confirm that MS occurs more frequently in central Italy than might be expected on the basis of the geographic-related distribution model, thus supporting the view that this is a high-risk area for the disease.

Validity of six balance disorders scales in persons with multiple sclerosis

PURPOSE

The aim of this study was to test concurrent and discriminant validity of several tests of static and dynamic balance in a sample of subjects suffering from MS.

METHOD

A group of 51 patients were enrolled in the study. The following tests were administered: Berg Balance Scale (BBS), Timed Up and Go Test (TUG), Dynamic Gait Index (DGI), Hauser Deambulation Index (DI), Dizziness Handicap Inventory (DHI), and Activities-specific Balance Confidence (ABC). The scales used in this study were initially translated into Italian.

RESULTS

The sample of subjects reported a mean of 0.98 (1.8 SD) falls in the month prior to evaluation. The tests demonstrated good concurrent validity: Higher correlation coefficients among tests tapping the same aspect and lower correlation coefficients among tests tapping slightly different aspects. ABC and DHI tests discriminated better than the others between fallers and non-fallers and appeared the best predictors of fall status. BBS and DGI were not as efficient in discriminating between groups. Conversely all tests showed good difference validity in the prediction of patients who used an assistive device.

CONCLUSION

BBS, TUG, DI, DGI, ABC, DHI have acceptable concurrent validity. The scales have poor performance in discriminating between faller and non-faller.

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

Studies on the distribution of multiple sclerosis (MS) carried out in Southern Europe in the last years have shown a significant increase in the frequency of the disease. A previous descriptive survey in the Republic of San Marino, northern Italian peninsula, published in 1984 established that this area is at high risk for MS. We updated the frequency estimates of the disease by adopting a complete enumeration approach. On 31 December 2005, 50 MS patients (36 women and 14 men) yielded a crude prevalence rate of 166.7 per 100, 000 (95% CI 123.7-220), 235.3 (95% CI 165-327.4) for women and 95.2 (95% CI 52-160) for men. The average incidence from 1990 to 2005 was 7.9 (95% CI 5.3-11.1) per 100,000, 11.7 (95% CI 7.6-17.3) for women and 3.9 (95% CI 1.7-7.7) for men. We did not detect any significant temporal trend over the study period. These results confirm that in San Marino the disease occurs more frequently than that suggested in the past and support the data on MS frequency in continental Italy. The marked increase in MS prevalence ratio is partly due to the increasing survival of patients and the accumulation of new incidence cases owing to the reduction in diagnostic latency for better quality of neurological diagnostic procedures. However, an increased incidence of the disease could be considered.

Multiple sclerosis in the province of Ferrara : evidence for an increasing trend

BACKGROUND

Epidemiological studies on the distribution of multiple sclerosis (MS) conducted in the Mediterranean area in the last two decades have disclosed a significant increase in frequency of the disease, indicating caution when a latitude-related model of MS is accepted. Previous descriptive surveys in the province of Ferrara, northern Italy, carried out by our own epidemiological research group, have established that this area is at high risk for MS.

OBJECTIVE

To confirm the above assumption and to update MS frequency estimates in this area.

DESIGN AND SETTING

We conducted a community-based intensive prevalence and incidence study, by adopting a complete enumeration approach.

RESULTS

On December 31, 2004, 423 patients (300 women and 123 men) suffering from definite or probable MS (Poser's criteria) living in the province of Ferrara, yielded a crude prevalence rate of 120.93 (95 % CI, 110.05-134.23) per 100,000, 164.26 for women and 73.59 for men. The average incidence from 1990 to 2003 was 4.35 per 100,000 (95 % CI, 3.77-4.99), 5.91 for women and 2.63 for men. The incidence rate,which was relatively stable during the previous 25 years (1965-1989) with a mean rate of 2.3 per 100,000, increased to a value of 3.39 per 100,000 in the period 1990-1994, 4.09 per 100,000 in the period 1995-1999 and 3.84 per 100,000 in the period 2000-2003.

CONCLUSIONS

These results confirm that in Ferrara MS occurs more frequently than suggested by the geographic- related distribution model and, based on other recent national surveys, support the view that northern Italy is a high-risk area for the disease. The marked increase in MS prevalence rate, in comparison with previous investigations, is in part due to the increasing survival of patients as a result of improved supportive care and the accumulation of new incidence cases owing to the reduction in diagnostic latency for better quality of neurological diagnostic procedures. The incidence in the province of Ferrara was found to slowly change with an incremental trend,which cannot only be attributed to improvements in diagnostic ability. Environmental risk factors in genetically predisposed people over time could be considered.

A possible spatial and temporal cluster of multiple sclerosis in the town of Linguaglossa, Sicily

We carried out an epidemiological survey to determine prevalence and incidence of multiple sclerosis in the little town of Linguaglossa in the Province of Catania. We calculated prevalence rate as point prevalence at 1 January 2001 and incidence during 1991-2000. We studied the frequency of multiple sclerosis in the community of Linguaglossa in a population of 5,422 inhabitants in the 2001 census. The primary sources for the case ascertainment were the general practitioners of Linguaglossa, the local Italian Multiple Sclerosis Association and the neurological departments, Multiple Sclerosis Centers and private neurologists of the province of Catania. We considered as prevalent and incident cases all patients who satisfied the Poser's diagnostic criteria. We detected 11 patients with multiple sclerosis who had had the onset of disease on prevalent day (P.D.). The onset-adjusted prevalence rate was 203/100,000 (95% CI 107-352). Prevalence was higher in women (247/100,000) than in men (154/100,000). From 1991 to 2000, 10 subjects with MS had clinical onset of disease. The mean annual incidence risk was 18.2/100,000 (C. I. 95 % 5.9-42.5). Conversely in the same population prevalence on 1 January 1991 was 37/100,000 while the onset adjusted annual incidence risk during the previous decade (1981-1991) was 3.6/100,000. Prevalence and incidence rates of MS during the last decade in the little town of Linguaglossa are higher than those found in the same area during the previous ten years and also than those reported in other Sicilian and Italian surveys suggesting a possible cluster of MS.

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.

Increasing frequency of multiple sclerosis in Padova, Italy: a 30 year epidemiological survey

OBJECTIVE

To determine the incidence and prevalence rates of multiple sclerosis (MS) and their temporal profiles over the last 30 years in the province of Padova (northeast Italy).

BACKGROUND

In the early 1970s an epidemiological survey in the province of Padova showed a MS prevalence and incidence of 16/100 000 and 0.9/100 000 population, respectively; these figures are much lower than current estimates in other regions of Italy and Central Europe.

METHODS

The population of the study area was approximately 820 000 (422 028 women, 398 290 men) in the 1991 census. All possible sources of case collection were used, but only clinically definite/probable and laboratory-supported definite/probable MS were considered in the analysis of incidence and prevalence trends from 1971 to 1999.

RESULTS

On 31 December 1999, the crude prevalence rate was 80.5/100 000 (95% CI 70.3-90.7); prevalence was higher in women (111.1/100 000; 95% CI 99.0-123.1) than in men (49.7/100 000; 95% CI 41.3-58.1). This difference was significant (F/M = 2.43; z = 10.1, P < 0,00001); a rate adjusted for the European population was 81.4/100 000. On 31 December 1980 and on 31 December 1990 the estimated prevalence rates were 18/100 000 and 45.7/100 000, respectively. Thus, a fivefold increase in prevalence was observed from the 1970s. The mean annual incidence was 2.2/100 000 in the period 1980-89, 3.9 in the period 1990-94 and 4.2 in the period 1995 99. Thus, incidence increased more than fourfold from the 1970s through 1994 and remained quite stable in the last several years. Mean age at onset was 31.3 +/- 9.88 years. Mean diagnostic latency decreased significantly from 49.2 +/- 44.5 months in 1985 to 23.0 +/- 30.3 months in 1990, 12.9 +/- 15.61 in 1995 and 5.3 +/- 4.7 in 1999.

CONCLUSIONS

The actual prevalence (80.5/100 000) and incidence (4.2/100 000) of MS in the province of Padova agree with the most recent epidemiological estimates/trends observed in other Italian and European areas, except for Sardinia and Scotland. The increase in both incidence and prevalence rates observed in much of this region over the last 30 years parallels the introduction of more sensitive diagnostic techniques and a highly significant decrease in diagnostic latency. These findings probably do not support a real increase in the frequency of MS in northeast Italy because recent estimates of incidence have increased only slightly (3.9 to 4.2, which is < 10% in five years) and increase in the prevalence rate was almost completely due to the accumulation of new incidence cases.

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.

Prevalence of multiple sclerosis in Belgrade, Yugoslavia

OBJECTIVES

To estimate the distribution of multiple sclerosis in the Belgrade population.

METHODS

All persons who were affected and/or died from multiple sclerosis (Poser's criteria), with residence in the Belgrade region had been collected from January 1, 1985 to December 31, 1996. Prevalence was adjusted by direct method, using world population.

RESULTS

From 1985 to 1996, 823 patients were suffering from multiple sclerosis. Sex ratio was 1:1.9. The mean age at onset was 32.2 +/- 9.8 years. A relapsing-remitting course of multiple sclerosis was reported in 50.7% patients, secondary progressive in 36.4%, patients, and primary progressive in 12.9% patients. On December 31, 1996, age-adjusted prevalence of multiple sclerosis in Belgrade was 41.5/100,000, 28.2/100,000 for males, and 54.1/100,000 for females. During the period studied, statistically highly significant increasing trend of multiple sclerosis prevalence was observed (P = 0.0001).

CONCLUSIONS

According to findings presented in this study, Belgrade is an area with high prevalence of multiple sclerosis.

The prevalence of multiple sclerosis in the city of São Paulo, Brazil, 1997

July 1, 1997 was stipulated as the day for estimating the prevalence of multiple sclerosis within the city of São Paulo. The patients were identified via various sources, including associated universities and magnetic resonance services of the city of São Paulo. The area covered by the study has a population of 9,380,000, mainly white and of European origin, with a large number of immigrants from Spain and Portugal. The patients were classified in accordance with the criteria of Poser et al. (1983), and only those with defined multiple sclerosis were registered. The study gave a prevalence of 15.0/10(5) inhabitants, or three times the value obtained in a similar study in 1990. This increase reveals the larger number of cases encompassed by the study, and is attributed to the use of more detailed recording methods, improvements in diagnosis, and better conditions for treatment.

Association between the ancestral haplotype HLA A30B18DR3 and multiple sclerosis in central Sardinia

Association and linkage studies have established the importance of the major histocompatibility complex (MHC) in the susceptibility for multiple sclerosis (MS). We carried out a case-control study to investigate the ancestral haplotype A30B18DR3 and MS in the Nuoro population of Sardinia, which is isolated and genetically distinct from other populations in the Mediterranean basin and characterized by genetic homogeneity, high level of inbreeding, low migration, high prevalence of MS, high frequency of the relevant haplotype, and high past malaria prevalence. Cases and controls were serologically typed for the currently recognized HLA-A, B, and DR antigens. We used a log-linear approach to fit a wide class of models. We tested our hypothesis comparing different models via a likelihood ratio test. We overcame the complication due to unknown gametic phase using expectation-maximization (EM) algorithm as the estimation method. We estimated confidence intervals for odds ratio by using a profile likelihood approach. We found that: (1) the ancestral haplotype A30B18DR3 was associated to MS after allowing for a possible stratification in cases and controls; (2) DR3 allele was conditional independent on disease status, given A30B18 haplotype; (3) there was a tendency for ORs for the high-risk haplotypes to be higher in the high malaria strata; however, this indication did not achieve statistical significance (P = 0.11).

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.

The increasing incidence and prevalence of MS in a Sardinian province

OBJECTIVE

To verify incidence rates and their temporal trend in a homogeneous, ethnically, and genetically distinct population of central Sardinia (the Nuoro province).

BACKGROUND

Intensive epidemiologic studies carried out in Sardinia since the 1970s have suggested that the prevalence and incidence of MS are much higher in this Mediterranean island compared with those found on mainland Italy.

METHODS

The study area had a population of approximately 274, 000 people in the 1991 census. The authors adopted a complete enumerative approach by reviewing all possible sources of case collection available in the investigative area.

RESULTS

Based on 469 MS patients, the mean annual incidence for 1955 to 1995 was 4.18 per 100,000 (or 4.3 per 100,000 if age- and sex-adjusted to the European population). The incidence, averaging 1.95 per 100,000 during 1955 to 1959, rose progressively over time, reaching rates of 6.6 in the quinquiennium 1985 to 1989 and 6.4 per 100,000 in 1990 to 1995. On December 31, 1994, the crude prevalence, based on 415 MS patients alive in the study area, was 151.9 per 100,000 (156.6 if adjusted to the European population).

CONCLUSION

These incidence and prevalence rates are the highest to date that have been estimated for a large community in southern Europe, and they constitute some of the highest rates in the world. Based on other surveys, these results reinforce the position of Sardinia as a higher and rising prevalence area for MS compared with other Mediterranean populations. Genetic and social-historic data strengthen the hypothesis of the environmental role and genetic factors among Sardinians in determining the notable difference in MS frequency between Sardinians and other Mediterraneans.

Prevalence of multiple sclerosis in the L'Aquila district, central Italy

OBJECTIVE

To estimate the prevalence of multiple sclerosis in the L'Aquila district, central Italy.

METHODS

All available case sources were screened. Definite and probable cases of multiple sclerosis, classified according to the Poser criteria, were considered as prevalent cases.

RESULTS

On the prevalence day, 31 December 1996, 158 patients (105 women and 53 men; ratio 2:1) affected by definite (n=131) or probable (n=27) multiple sclerosis were alive and resident in the L'Aquila district. Mean (SD) age was 38.4 (11.9) years (38.9 (11.7) years for women and 38.5 (12.3) years for men, p=0.9). The overall crude prevalence was 53.0/100 000 (95% confidence interval (95% CI)=45.4-62.0); 68.4/100 000 (95% CI=56. 5-82.8) in women, and 36.7/100 000 (95% CI=28.1-48.0) in men. The prevalence was similar (55.9/100 000) when standardised to the 1996 European population. Mean (SD) age at onset of multiple sclerosis was 29.4 (9.6) years and mean (SD) duration of the disease was 9.4 (7.4) years, without any significant difference between sexes. Mean age at onset was significantly higher in patients with the primary progressive than in those with the relapsing-remitting course (p=0. 0002, Scheffé's test).

CONCLUSIONS

The prevalence found in the L'Aquila district gives support to the consideration of Italy as an area in which multiple sclerosis has been shown to have high prevalence at least in the populations that were surveyed recently.

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.

The prevalence of multiple sclerosis in the Hungarian city of Szeged

OBJECTIVES

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

METHODS

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

RESULTS

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

DISCUSSION

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

Multiple sclerosis in Gijon health district, Asturias, northern Spain

The objective of this study was to ascertain the prevalence and incidence of Multiple Sclerosis (MS) in a population of 33,775 in two primary health care centres in the sanitary district of Gijon, Asturias, northern Spain. Many information sources were used but the unique advantage of Gijon was that the city has a centralized computerized register of all diagnoses made for all consultations in the clinics and hospitals in the area. The HLA distribution in the population was already known and the Poser classification of MS was used. The crude MS prevalence was 65/100,000, a similar prevalence to that found in southern and eastern Spain, Sicily and Greek-speaking Cyprus. The mean incidence was 3.7/100,000 per year. The study demonstrated the advantage of a centralized and computerized medical recording system and demonstrates that northern Spain is a moderately high or medium MS risk zone.