Prevalence of MS in South Estonia. Evidence of a new border of the Fennoscandian focus

A population-based study of MS was carried out in South Estonia in 1988–1989. Cases were identified from the Tartu University Hospital archives where all MS cases in South Estonia are diagnosed, from all neurologists and nursing homes of the region, and from the local Multiple Sclerosis Society. The prevalence in South Estonia is 51 per 100,000, for native Estonians 55, for Russians 29, for other nationalities 42 per 100,000. The prevalence rate in different counties was demonstrated as low as 31 per 100,000 in the County of Tartu, to 72 per 100,000 in Plva County; 55% of patients have retired because of their handicap and only 2 patients (1%) were living in nursing homes.     

Epidemiological study of motor neuron disease in Hokkaido island--its incidence, prevalence and regional distributions--ALS Study Group]

The incidence, prevalence and regional distributions of sporadic motor neuron disease (MND) from 1980 through 1989 were evaluated in collaboration with multiple neurological institutes in Hokkaido island. Patients with sporadic MND were collected from three sources: 1) neurologist practicing in Hokkaido island, 2) sending inquiries to 620 major hospitals, 3) notification file of MND provided by Japanese Ministry of Welfare and Health. Three hundred and eighty-nine patients with sporadic MND were ascertained for this study. Of 389 patients, 238 patients were men and 151 patients were women, and the ratio of men to women was 1.6:1. The mean age of onset was 58.2 +/- 10.3 years old, 57.7 +/- 10.4 for men and 58.9 +/- 10.0 for women. Their clinical presentations were 303 patients with ALS, 52 patients were PBP and 34 patients were SPMA. The crude incidence rate for both sexes combined for 1980 through 1989 was estimated as 0.69 per 100,000 person-year. The age- and sex-adjusted incidence for men was 0.86 per 100,000 person-year (95% CI, 0.75 to 0.97) and that is higher than 0.53 per 100,000 person-year (95% CI, 0.45 to 0.61) for women. The average, crude prevalence rate from 1985 through 1989 was estimated as 2.25 per 100,000 person-year. There are no overall trends of changing the pattern in incidence and prevalence of MND in Hokkaido island, however the geographic distributions of the incidence of MND according to towns and cities disclosed the presence of some relative clustering areas.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence and incidence of multiple sclerosis in Oppland County: a cross-sectional population-based study in a landlocked county of Eastern Norway

Risberg G, Aarseth JH, Nyland H, Lauer K, Myhr K‐M, MidgardR. Prevalence and incidence of multiple sclerosis in Oppland County – a cross‐sectional population‐based study in a landlocked county of Eastern Norway.
Acta Neurol Scand: 2011: 124: 250–257.
© 2010 John Wiley & Sons A/S. Objectives – We report the prevalence and incidence rates of multiple sclerosis (MS) in Oppland County, Norway. Methods – Records from all patients diagnosed with MS at the two Oppland County hospitals, Gjøvik and Lillehammer during 1989–2001 were evaluated. In addition, all general practitioners in Oppland County reported their patients into the study. Results – The age‐adjusted prevalence rate of definite MS was 174.4/ 100 000 on the prevalence day 1 January 2002. When the probable cases were included, the prevalence rate rose to 185.6/100 000. The highest prevalence rates were detected in the northern mountain areas, thus corroborating the results from previous local surveys 30–50 years ago. The prevalence of MS was statistically significantly associated with climatic, socioeconomic and geographic variables in the county. The age‐adjusted incidence of definite and probable MS in Oppland County was 6.6/100 000 during 1989–1993 increasing to 7.6/100 000 during 1994–1998. Discussion – We found the highest prevalence rates of MS ever reported in Norway. Our findings indicate a possible influence of environmental factors.     

Multiple sclerosis: genetic versus environmental aetiology: epidemiology in Israel updated

The incidence and prevalence of multiple sclerosis (MS) were compared, controlling for age, in native-born Israelis of different origins and in immigrants to Israel. This comparison was carried out in two populations, countrywide and in Jerusalem. In the countrywide population, ascertainment was based mainly on hospitalizations; it included 252 patients who were native-born and 150 who had immigrated from Africa-Asia (AA immigrants). The 89 MS patients of Jerusalem also included patients diagnosed in outpatient clinics. In native-born Israelis whose father was born in Europe-America (I-EA), the incidence and prevalence of MS were found to be as high as or even higher than that found previously in immigrants from Europe-America. Among native-born Israelis whose father was born in Africa or Asia (I-AA), the yearly age-adjusted incidence and prevalence rates were found to be 1.4- to 1.8-fold higher than among AA immigrants, pointing to environmental factors. The incidence and prevalence rates in the I-EA were 1.2- to 1.6-fold higher than in the I-AA, pointing to genetic factors. These results seem to point to both environmental and genetic factors in the aetiology of MS. Further research is needed, however, to disentangle the genetic factors from possible environmental differences in the two ethnic groups.     

Prevalence and pattern of multiple sclerosis in Benghazi, north-eastern Libya

A search for Libyan patients with multiple sclerosis (MS) was made in Benghazi, located on the southern Mediterranean coast at a latitude of 32 degrees N. Twenty-one clinically definite and probable cases were detected during the period July 1982-June 1984. On the basis of 2 probable incidental cases, the incidence for 1983 was 0.8 per 100 000 of the population at risk (10-50 years). On July 1st, 1984, the rough prevalence rate for the total population was 4 per 100 000 and the age-adjusted prevalence rate was 5.9 per 100 000. This study suggests that Benghazi falls within the medium frequency band for MS. High prevalence of brainstem involvement and cerebellar dysfunction and infrequent occurrence of the severe optic-spinal form and sphincter disturbance indicates that the present group of patients resembles Western pattern of MS as opposed to Asian MS.     

Incidence of multiple sclerosis in Bagheria City, Sicily, Italy

We investigated the incidence of multiple sclerosis (MS) in a Sicilian community located a sea level. The study was a retrospective search for MS patients. Incidence was studied in the period from 1 January 1985 to 31 December 1994. We searched for definite MS patients, according to Poser's criteria, among the population resident in Bagheria (Palermo province). There were 25 subjects affected by MS, of which 20 were incident MS patients. The average annual incidence was 4.4 per 100 000 persons (n = 453 385 person-years). The incidence increased over time (1985–1989 = 3.5, 1990–1994 = 5.3). A parallel decrease of the interval between onset and diagnosis of MS was observed (1985–1989, 3.7 years, 95% CI = 1.6–7.3; 1990–1994, 1.9 years, 95% CI = 1.0–3.3). These results confirm that MS is frequent in Sicily. Received: 19 October 2000 / Accepted in revised form: 18 December 2000     

Epidemiology of multiple sclerosis in Arabs in Kuwait: A comparative study between Kuwaitis and Palestinians

On December 31, 1988 there were 201 registered multiple sclerosis patients in Kuwait, an overall prevalence rate (PR) of 10.2 per 100000; among them were 186 Arabs, of whom 72 were Palestinians and 51 Kuwaitis. Comparison of these two subgroups, who had a similar age distribution revealed that the disease was2 1/2 times more frequent among Palestinians (PR 23.8/100 000) than among Kuwaitis (PR 9.5/100 000). Palestinians also showed significant differences from Kuwaitis in eye color, blood group distribution and HLA-DR and HLA-DQW epitopes frequency. This suggests that genetic rather than environmental factors might be the underlying cause for the high susceptibility to develop MS among Arabs originating from the Eastern Mediterranean basin.     

An all-Ireland epidemiological study of MND, 2004–2005

Background and methods:  We conducted an all-Ireland population-based prospective epidemiological survey of motor neurone disease (MND) using the Northern Ireland and Republic of Ireland MND registers to examine the incidence and prevalence of the disease over the period 2004–2005.
Results and conclusions:  Incidence of MND was 1.9 per 100 000 person-years and rates were comparable in both the north and south of Ireland. Prevalence of MND was 5.0 per 100 000 population. When compared with previous published surveys of MND performed in the Republic of Ireland over the last 10 years, rates of disease have remained relatively constant. When standardized to the 1990 US population, the incidence of MND in Ireland was found to be consistent with other European prospective surveys of MND.     

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.     

Motor neuron disease in the Province of Turin, Italy, 1971-1980

The incidence and prevalence of motor neuron disease (MND) in the Province of Turin, North-West Italy, were investigated for the period 1971-1980. The crude incidence rate of MND was 0.67/100,000/year. The annual incidence rate, age and sex adjusted to the Italian population in 1971 was 0.69 cases per 100,000 inhabitants, 0.94 for men and 0.45 for women, with a male to female incidence ratio of 2.09:1. The prevalence of MND was 2.62/100,000, 3.57 for males and 1.71 for females. The mean age at the time of diagnosis was 55.6 years. Annual incidence rates increased with advancing age. Amyotrophic lateral sclerosis was found to be 4 times more frequent than progressive muscular atrophy (0.53/100,000/year v. 0.14/100,000/year). The distribution of MND was uneven in the Province suggesting a proportional relationship to the distribution of population density. Possible explanations of this finding are discussed.     

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.     

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.     

A systematic review of the epidemiology of multiple sclerosis in South America

Hundreds of publications dealing with the prevalence of multiple sclerosis (MS) throughout the world exist, but little data have been published from South America. Epidemiological studies of MS vary according to environmental, racial and genetic factors; a better understanding of MS in South America would help us to elucidate the disease pattern in this population. The aim of this study is to review the evidence relevant to MS epidemiology in South America. We performed a systematic review of articles of MS epidemiology in South America, with special emphasis on those providing information on the incidence and prevalence of MS (population‐based studies). Six papers provided information on MS epidemiology. One paper used the capture‐recapture methodology, while the remainder employed traditional methods to collect the data. Population‐based studies showed an MS prevalence rate ranging from 1.48 to 17 per 100 000 inhabitants. Available data suggest that the prevalence of MS is lower in South America than in developed countries. The reason for this observation is unknown. Some investigators suggest that certain environmental factors like sun exposure and vitamin D supplementation or the called ‘hygiene hypothesis’ may protect this population. Future studies will contribute to elucidate the etiology of that difference.     

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.     

Incidence and lifetime risk of motor neuron disease in the United Kingdom: a population-based study

Background and purpose:  To estimate the incidence and lifetime risk of motor neuron disease (MND) in a population-based sample in the United Kingdom.
Methods:  We identified new cases of MND during the period 1990–2005 in the General Practice Research Database, which includes clinical information from more than 3 million Britons enrolled with selected general practitioners. Individuals with a first medical diagnosis of MND recorded in the database were considered incident cases of the disease. The positive predictive value of the computer-based diagnosis was estimated through review of a sample of medical records from potential MND cases.
Results:  In the period 1990–2005, 830 new cases of MND were identified. Age-standardized incidence of MND was 2.6 per 100 000 persons per year in women (95% CI: 2.3, 2.8) and 3.9 in men (95% CI: 3.6, 4.3). Incidence for both sexes peaked between 75 and 79 years. The rate of MND in men was 54% higher than in women (95% CI: 33%, 77%). The lifetime risk of MND, adjusting for competing causes of death, was 1 in 472 (2.1 per 1000) in women and 1 in 350 (2.9 per 1000) in men. No increase in MND incidence over time was apparent.
Conclusion:  In this population-based database, we found that MND incidence is higher in men than women, peaking in both sexes between 75 and 79 years.     

Epidemiology of multiple sclerosis in northern Greece

A total of 638 new cases of multiple sclerosis (MS) (365 females, 273 males) were found from 1970-1984 in northern Greece (Macedonia and Thrace); the average annual incidence rate was 1.79 per 100,000 inhabitants with increasing incidence from 1980-1984. A total of 729 people living in northern Greece suffered from MS on December 31, 1984 (prevalence rate 29.5 per 100,000 inhabitants). No difference was found between urban and rural areas. No difference from the international standards was found for sex incidence. The study confirms the quite high prevalence of MS despite the fact that northern Greece is in the intermediate risk zone.     

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.