Epidemiological data of multiple sclerosis in the province of Evros,Greece

The frequency of multiple sclerosis (MS) in Greece is still debated. Our previous epidemiological field survey with a cross-check study of MS on March 31, 1984, in the province of Evros in north-eastern Greece showed a prevalence rate of 10.1/100,000. In 1990, Milonas et al. recorded a prevalence rate of 29.5/100,000 in northern Greece. So Greece is classified in the medium-frequency zone according to Kurtzke. This study was performed to estimate the prevalence of MS in the province of Evros and the annual incidence rates from 1974 to 1999. Patients were identified from several sources. A clinical follow-up was performed in 95% of the cases, and, if clinically indicated, new paraclinical examinations were performed and cases classified by Poser's criteria. The prevalence rate of the definite MS cases on December 31, 1999, was 38.9/100,000 and places the area in the high-risk zone. The mean annual incidence measured in 5-year intervals increased from 0.66/100,000 in 1974-1978 to 2.36/100,000 in 1994-1999 (p < 0.01). The increase in prevalence can be attributed to other causes than etiological changes, but the increase in the annual incidence rate indicates the possibility of a variation in risk factors of the disease.     

Frequency of multiple sclerosis in Valle d'Aosta, 1971-1985

According to studies done before 1980, the multiple sclerosis (MS) prevalence rate in Italy ranged from 7.2 to 27.1 cases per 100,000 inhabitants. More recent work has consistently put the MS prevalence rate to over 30 cases per 100,000 inhabitants. If these recent data are confirmed in the future, Italy can no longer be regarded as a country at low risk for MS, but must be included among the medium-high risk countries of continental Europe. We report the results of a prevalence and incidence survey conducted in Valle d'Aosta, a region whose special features make it an excellent epidemiological model. The mean annual incidence was 2.1 and on December 31, 1985, the prevalence was 39 cases per 100,000 inhabitants. These results confirm that the incidence and prevalence rate of MS in Valle d'Aosta is close to that of areas at high-risk for MS.     

Prevalence rate of cerebrovascular disease in the rural population of northwest Peloponnese, Greece. A direct epidemiological study

In a direct (door-to-door) epidemiological study, the prevalence rate of cerebrovascular disease in the rural population of northwest Peloponnese, Greece, was found to be 995 strokes per 100,000 inhabitants over 20 years of age. This number is considerably lower than the prevalence rate (1,417 strokes per 100,000 inhabitants over 20 years of age) found in the urban population of the same county (Patras, Greece).     

A reappraisal of the epidemiology of multiple sclerosis in Olmsted County, Minnesota

A review of multiple sclerosis (MS) case reports, using the unified record system at the Mayo Clinic for the Olmsted County population, revealed age- and sex-adjusted prevalence rates per 100,000 persons of 160 for Olmsted County and 173 for Rochester, Minnesota, on January 1, 1985. The annual age- and sex-adjusted incidence rate per 100,000 person-years from 1975 to 1984 for Olmsted County was 6.2 and for Rochester, 6.3. This incidence rate is significantly higher than what had been reported previously in Rochester (3.6/100,000) or in other communities. The estimated 25-year survival of the MS population was 76.2% +/- 4.5% compared with 87.7% for the general US white population of a similar age and sex. Survival for men was less than for women. There was no increase in survival for patients diagnosed with MS in more recent decades. No significant increase was found in cancer or autoimmune disease rates in the MS patients.     

Estimating the prevalence and incidence of multiple sclerosis in the Lorraine region, France, by the capture-recapture method

OBJECTIVE: The objective of this study was to assess the prevalence and incidence of multiple sclerosis (MS) in the Lorraine region, in France. METHODS: Data from three sources - Regional Health Insurance System, medical records departments and the Lorraine registry of MS - and a capture-recapture method with log-linear models were used to estimate the prevalence and incidence of MS. RESULTS: We identified 7193 records of reported MS corresponding to 4299 unique suspected cases of MS existing on 31 December 2008, in Lorraine. On the basis of the 4001 validated cases, the observed crude prevalence of MS was 170.9 cases per 100,000 inhabitants (95% confidence interval [CI]: 165.7; 176.3), and the observed annual crude incidence of MS was 4.4 cases per 100,000 inhabitants (95% CI: 3.6; 5.4). With the capture-recapture method, the estimated prevalence of MS was 4405.7 (95% CI: 4261.5; 4629.7), so an estimated 405 cases were not identified by the three sources. The estimated prevalence was 188.2 cases per 100,000 inhabitants (95% CI: 182.7; 193.8), and the estimated annual incidence was 8.5 cases per 100,000 inhabitants (95% CI: 7.3; 9.7). CONCLUSIONS: The capture-recapture method allowed us to estimate an additional 10.1% of unobserved prevalent cases and to anticipate 47.5% of unobserved incident cases.     

Incidence and prevalence of motor neuron disease in Coastal and Mountainous Regions,Croatia, 1984–1993. A preliminary survey

In the period 1984–1993, we carried out an incidence and prevalence study of motor neuron disease in Coastal and Mountainous Regions, Croatia. This was the first epidemiological study on motor neuron disease in Croatia. A total of 22 incident cases were identified. The crude annual incidence rate was 0.68 (95% confidence interval 0.43-1.03) per 100,000 person-years; 0.95 (95% confidence interval 0.60-1.43) per 100,000 person-years for men and 0.42 (95% confidence interval 0.26-0.63) per 100,000 person-years for women. The rate adjusted to the European population was 0.63 (95% confidence interval 0.39-0.95) per 100,000 person-years. The age-adjusted incidence in our population is similar to the rates, standardized to the European population, observed in Italy, but lower than recent rates in the US and northern European studies. On 31st December 1993, there were 18 prevalent cases. The prevalence adjusted to the European population was 5.24 (95% confidence interval 3.10-8.28) per 100,000 population.     

The prevalence rate of cerebrovascular disease in Patras, Greece. A direct epidemiological study

In a direct (door-to-door) epidemiological study, the prevalence rate of cerebrovascular disease in Patras, Greece, was found to be 1,417 strokes per 100,000 inhabitants over 20 years of age. This number is approximately two times higher than the prevalence rate found in other countries by other authors. The possible responsible factors for this difference are discussed.     

Multiple sclerosis in Nord-Trøndelag County, Norway: a prevalence and incidence study

Objective – To calculate the prevalence and incidence of multiple sclerosis (MS) in Nord‐Trøndelag County, Norway. Material and methods – The study comprised everyone diagnosed with MS according to the Poser criteria. On 1 January 2000 a total of 208 were identified: 130 women (62.5%) and 78 men (37.5%). We calculated the crude and age‐adjusted annual incidence rates from 1974 to 1999. Results – The prevalence on 1 January 2000 was 163.6 of 100,000, 204.8 of 100,000 for women and 122.6 of 100,000 for men. The age‐adjusted annual incidence increased from 3.9 to 5.6 per 100,000 from 1974 to 1999; women from 4.6 to 6.3 and men from 2.2 to 4.4. After 1984, the incidence among women increased most, peaking at 10.2 per 100,000 in 1984–88. Conclusions – MS incidence is increasing in Nord‐Trøndelag County. The prevalence is among the highest ever in Norway.     

Trends in prevalence and incidence of multiple sclerosis in Bajo Aragón, Spain

OBJECTIVE: Recent reports provide consistent evidence that Spain is an area of high risk for multiple sclerosis (MS) according to prevalence surveys. However, the studies of incidence are scarce. The objective of the current work is to analyse whether the increased prevalence of MS is accompanied by increasing incidence in the area of Bajo Aragón, northeastern Spain. METHODS: The data of both prevalence and incidence were retrieved from a prospective register created in 1994 and which included patients with probable or definite MS. Crude and age-standardised rates were calculated from 1994 to 2002 and compared with those found retrospectively in the previous period of 1984-1993. RESULTS: In January 2003, we found a prevalence rate of 75/100,000 (95% CI: 52-97) whereas it was 35/100,000 (95% CI: 20-50) in 1994. In a period of 9 years, 25 new cases were diagnosed in the area with a mean annual incidence rate of 4.6/100,000 (95% CI: 2.8-6.5; range: 1.6-13.6) in comparison to 17 new cases from 1984 to 1993 with a mean incidence rate of 3/100,000 (95% CI: 1.6-4.5). The standardised ratio of incidences was 1.44 (95% CI: 0.95-2.17) and, therefore, the difference of rates was not significant. CONCLUSION: We conclude that the increase in prevalence of MS is more likely to be due to improvement on case ascertainment than to increasing incidence. Nonetheless, further prospective incidence studies in larger populations are warranted in Spain to elucidate whether the frequency of this disease is truly increasing.     

The organisation of health care and epidemiology of multiple sclerosis in France

STATE OF THE ART: According to the available previous studies, France is considered a zone of medium to high risk of multiple sclerosis (MS) with an estimated overall prevalence of at least 50/100,000 inhabitants, incidence rates were stable in some areas but increased over time in others and a strong ethnic effect on the incidence, clinical presentation, and course of MS is reported. RESULTS: Based on two health insurance survey the prevalence has been deduced. At January 1, 2003 from the data of agricultural health insurance the prevalence is evaluated at 65.5/100,000 inhabitants (95p.cent CI=62.5-67.5) with a gradient of North East towards South-West. The data from the national health insurance were very near. During the period 2000-2004, recent studies in Auvergne and Brittany demonstrated an annual incidence comprising between 4.2 and 5.1 per 100,000 inhabitants. In Lorraine, in a large population-based study, in December 31, 2004 the prevalence rate was 120/100,000 (95p.cent CI: 119 to 121). During the period 1990-2002, the average age- and sex-adjusted annual incidence rate was 5.5/100,000 (95p.cent CI: 4.4-6.6). In Lorraine, we found that the age-adjusted incidence rate increased during the period 1990-2002. The incidence of MS in women increased, whereas that in men did not change significantly during this period. Similarly, in Norway, North Ireland and Denmark, the incidence among women increased the most. The clinical features of MS were compared in 211 North Africans patients and 2 945 Europeans patients in two French MS centres (Lorraine and Nice) with definite MS according to McDonald's criteria. The course of MS appears more aggressive in North Africans than in Europeans patients. For example, we demonstrated a shorter time to reach the Expanded Disability Status Scale score of 4.0 (p=0.001) or 6.0 (p<0.0001) in North Africans patients. PERSPECTIVES AND CONCLUSIONS: The incidence rates found in these studies were comparable to those reported in several European populations. This undoubtedly places France in the category of regions with a high risk zone of MS. The incidence of MS in women increased; thus, exogenous (or epigenetic) factors vary over time and may affect men and women differently. The course of MS appears more aggressive in North Africans than in Europeans patients.     

Epidemiologic survey of multiple sclerosis in the Bucharest city and suburban area

Epidemiologic survey over a restricted area of Romanian territory, i.e. the city of Bucharest with a population of 1,934,052 and a surface of 605 km², established the following values for the MS parameters studied.
On January 5, 1977 the prevalence rate for "probable" and "possible" cases was 46.4 per 100,000 inhabitants and for "probable" cases alone (with certain clinical diagnosis) 41.3 per 100,000.
The specific 20- to 60-year age adjusted prevalence rate was 79.4 per 100,000. The incidence rate over the 1969–1976 period was 1.78 per 100,000.
The prevalence and incidence rates in this survey are similar to those reported for two other large urban centers of Romania (population over 100,000 each), Romania being therefore situated in a geographical area of "high risk" for MS.
The 0.61 per 100,000 nationwide and the 0.65 per 100,000 Bucharest mortality rates are lower than those reported in other geographical areas of "high risk" for MS.     

Prevalence and incidence of multiple sclerosis in Catania, Sicily

OBJECTIVE: An epidemiologic survey was conducted to determine the prevalence and incidence of MS in the city of Catania, Sicily, Italy. Prevalence rate was calculated as point prevalence at January 1,1995, and incidence during 1974 to 1995. METHODS: The authors studied the frequency of MS in the community of Catania in a population of 333,075 inhabitants according to the 1991 census. The primary sources for the case ascertainment were the neurologic and motor rehabilitation departments, the MS Center, the Italian MS Association, private neurologists, and family doctors. All patients who satisfied the Poser criteria for clinically definite MS, laboratory-supported definite MS, clinically probable MS, and laboratory-supported probable MS were considered prevalent and incident cases. RESULTS: One hundred ninety-five patients with MS who had had the onset of disease on prevalence day in a population of 333,075 inhabitants were detected. The prevalence rate was 58.5 per 100,000 (95% CI 50.7 to 67.5). Prevalence was higher in women (62.0/100,000) than in men (54.8/100,000). The age-specific prevalence showed a peak in the group aged 35 to 44 (145.1/100,000). From 1975 to 1994, 170 subjects with MS had the clinical onset of the disease. The mean annual incidence was 2.3 per 100,000 (95% CI 2.0 to 2.6). Age-specific incidence showed a peak in the group aged 25 to 34 (6.32/100,000). Incidence for 5-year intervals increased from 1.3 during 1975 to 1979 to 3.9 during 1990 to 1994. CONCLUSIONS: These prevalence and incidence rates are close to those reported in other similar surveys carried out in Italy and southern Europe.     

Multiple sclerosis in North Norway, and first appearance in an indigenous population

This study was performed to determine the prevalence of multiple sclerosis (MS) in 1993 and annual incidence rates 1983-1992, and to examine whether the disease occurs among the Sami people. According to earlier reports the two northernmost counties of Norway, Troms and Finnmark with 225,000 inhabitants, have a relatively low prevalence of MS: 20.6 per 100,000 in 1973 and 31.5 in 1983. Also no person who is of pure Sami heritage (i.e., with both parents speaking Sami natively) has been found with the disease. Except for the introduction of magnetic resonance imaging as a diagnostic tool, there has been no significant change in the neurological service in the area during the past 20 years. Files of patients with the diagnosis of MS were reviewed, and questionnaires were sent to all patients alive on the prevalence day of 1 January 1993. The prevalence in 1993 was 73.0 per 100,000. The mean crude annual incidence rate was 3.5 per 100,000 during the period 1983-1992 compared with 3.0 during 1974-1982. In 1983 there were no pure Sami among the MS patients, but one had a Sami father. On 1 January 1993 there were three patients with both Sami parents and three with only one Sami parent, which is a rate that is still lower than would be expected if the prevalence of MS among the Sami were similar to that in the rest of the Norwegian population. The study shows that the incidence of MS in Troms and Finnmark has been increasing over the past 10 years, but is still lower than on the western coast and in the eastern part of Norway. The lowest incidence is found in Finnmark, where the Sami population is highest. During the past 10 years MS has also been diagnosed among the Sami population.     

The frequency of multiple sclerosis in Mediterranean Europe

Recent investigations on multiple sclerosis (MS) distribution in Italy, based on relatively small population groups, contradict the current thesis, derived from studies undertaken in populations exceeding 300,000, of a lower spreading of the disease in Mediterranean Europe. Intensive surveys on small populations strengthen the suggestion that Italy is a high-risk area, although MS studies based on prevalence rather than incidence could also be biased by geographic variables making prevalence unsuitable for comparing MS prevalence rates found in different years and/or zones. We report a further epidemiologic study in Barbagia, Sardinia, insular Italy, undertaken both to establish the MS incidence in the last 20 years, and to estimate a new prevalence rate. Based on 31 probable incident cases, the mean incidence per year for the years 1961-1980 was 2.9 per 100,000 (3.2 if age- and sex-standardized to the Italian population). On October 24, 1981, the prevalence per 100,000 was 65.3 (77.9 if standardized to the Italian population). These results confirm that in Barbagia, MS occurs more frequently than expected in a Mediterranean area, and give further support to the idea that MS frequency in Italy is similar to that established for most central and northern European countries.     

Prevalence and mortality of patients with multiple sclerosis in France in 2012: a study based on French health insurance data

Data on the prevalence of multiple sclerosis (MS) in France are scarce. National and regional updated estimates are needed to better plan health policies. In this nationwide study, we provided estimates of the prevalence of MS in France in 2012 and mortality rate in 2013. MS cases were identified in the French national health insurance database (SNIIRAM-PMSI) using reimbursement data for disease-modifying treatment, long-term disease status for MS, disability pension for MS, and hospitalisation for MS (MS ICD-10 code: G35). We identified 99,123 MS cases, corresponding to an overall crude prevalence rate of 151.2 per 100,000 inhabitants [95% confidence interval (CI) 150.3–152.2]: 210.0 per 100,000 in women (95% CI 208.4–211.5) and 88.7 per 100,000 in men (95% CI 87.6–89.7). The overall prevalence rate was 155.6 per 100,000 inhabitants (95% CI 154.7–156.6) after standardization on the 2013-European population. We observed a prevalence gradient with a higher prevalence (190–200 per 100,000) in North-Eastern France and a lower prevalence in Southern and Western France (126–140). The crude mortality rate in 2013 was 13.7 per 1,000 MS cases (11.4 in women and 20.3 in men). The standardized mortality ratio was 2.56 (95% CI 2.41–2.72). Our results revise upwards the estimation of MS prevalence in France and confirm the excess mortality of MS patients compared to the general population.     

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.     

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 > 90,188 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 100,000 inhabitants. The incidence of the disease in the study period was 5.3 cases per 100,000 inhabitants and year. CONCLUSIONS: The prevalence and incidence rates of MS found in Santiago de Compostela are the highest reported, to date, 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.