The prevalence of multiple sclerosis in the Southampton and South West Hampshire Health Authority

Evidence for a central mechanism in the process of fatigue in people with multiple sclerosis

The study aimed to establish quantitative and qualitative aspects of fatigue among a group of people with multiple sclerosis (MS) who had identified fatigue as a troublesome symptom and a control group of healthy adults. An interview, a fatigue diary and a fatigue-inducing experiment were designed and the Nottingham Health Profile was employed. People with MS experienced significantly more fatigue than healthy adults, on a daily basis. Factors noted to cause and to relieve fatigue were similar in people with MS and healthy adults. The only differences were that a hot bath improved fatigue in healthy adults and accentuated it in people with MS and that more of the healthy adults mentioned lack of sleep as a cause of fatigue. Physiological muscular fatigue during a quadriceps test was of similar magnitude in the two studied groups but the perceived fatigue levels were disproportionally high in the patient group. The results support the view that central mechanisms are responsible both for muscle weakness and for the sense of fatigue experienced so frequently in multiple sclerosis. This central mechanism is likely to reside in motor pathways within the nervous system. Further studies, measuring corticomotor conduction times, motor unit firing frequencies and metabolic factors, are recommended.

Multiple Sclerosis in Newfoundland and Labrador - A Model for Disease Prevalence

Background:

Newfoundland and Labrador, Canada, have been almost exclusively populated by immigrants from southwest England and southeast Ireland. The province’s population grew largely by natural increase from 20,000 people in 1835 to half a million at present. Very little interregional migration occurred within the province. This uniquely-populated region and its subsequent founder effect provide the basis to develop models of disease prevalence.

Objectives:

To develop a model for the regional prevalence of multiple sclerosis (MS), accounting for settlement patterns and geographic location (latitude).

Methods:

All living MS patients with confirmed addresses (438 patients) in the province were mailed a survey requesting their place of birth. Regional prevalences were calculated from a 75% rate of return of the survey. Theoretical regional prevalences were proportionally calculated from the source prevalences of southwest England, southeast Ireland, Scotland and the Channel Islands based on settlement patterns. These theoretical regional prevalences were corrected for geographical variations of latitude based on observations in the United Kingdom. Theoretical and actual regional prevalences were compared.

Results:

When actual regional prevalences were compared with theoretical prevalences, very little variation was noted, especially after correcting for variation in latitude.

Conclusion:

A regional variation in MS prevalence is noted in the island portion of Newfoundland and Labrador. This regional variation can be modeled by using both migration patterns and latitudinal position. This model demonstrates that the prevalence of MS is influenced by both genetic and environmental contributions.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

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.

MRI and visual-evoked potentials in partners of multiple sclerosis patients

OBJECTIVE

Some epidemiological evidence, particularly concerning the role of Epstein Barr Virus implies that multiple sclerosis (MS) may be transmissible and if correct, this might be revealed by increased prevalence of MS in cohabiting partners.

METHODS

We addressed this problem by neurological assessment, visual-evoked potentials (VEP) and magnetic resonance imaging (MRI) in 112 partners of patients with MS in comparison to a control group of 93 individuals with clinically non-significant head or neck pain and in comparison to UK prevalence.

RESULTS

We found one instance of conjugal definite MS. Including this case, VEP were abnormal in five instances with either significant delay (n = 3) or increased interocular latency difference (IOLD) (n = 2) in partners of MS patients thus raising the possibility of subclinical optic nerve demyelination. The mean absolute value of IOLD in partners was greater than the value in controls (P = 0.033). There were no significant differences in MRI findings between the two groups.

CONCLUSION

The finding of one conjugal pair and abnormal VEP in a further four MS partners could have several explanations. It is compatible with the concept of a transmissible agent, although our observations could be due to several biases as well as the play of chance alone.

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.

Shifting the paradigm toward earlier treatment of multiple sclerosis with interferon beta

BACKGROUND

Axonal damage occurs early in the course of multiple sclerosis (MS). Among untreated patients, 85% to 94% with a first clinically isolated syndrome (CIS) suggestive of MS and positive findings on magnetic resonance imaging (MRI) are at risk for developing MS.

OBJECTIVES

This article reviews the current literature concerning early diagnosis of MS, the rationale for early immunomodulatory treatment of patients with a CIS and MRI evidence of central nervous system lesions, and the efficacy of early treatment with interferon beta (IFN-beta).

METHODS

MEDLINE was searched from 1990 through the end of 2008 for papers published in English concerning the treatment of MS. Search terms included IFN-beta, early treatment, CIS, and multiple sclerosis, and limits were set to return results related to human clinical trials in adults.

RESULTS

Three pivotal randomized controlled trials were identified, 2 involving IFN-beta-1a (30 microg IM once weekly and 22 microg SC once weekly) and 1 involving IFN-beta-1b (250 microg SC qod). In these trials, treatment with IFN-beta effectively reduced the risk of developing MS by up to 50% in patients with a CIS. Furthermore, compared with delayed treatment, early treatment was associated with a reduced risk of disease progression: a 40% reduction in risk for confirmed disability progression at 3 years and a 41% reduction in risk of MS at 3 years.

CONCLUSIONS

The evidence that axonal damage begins in the early stages of MS, before symptoms are evident, provides a rationale for early intervention with immunomodulatory agents. In 3 pivotal clinical trials, IFN-beta effectively reduced the risk of developing clinically definite MS in CIS patients with a first demyelinating event and positive brain MRI.

Factors in the rising prevalence of multiple sclerosis in the north-east of Ireland

BACKGROUND

Northern Ireland is recognized as an area of high risk for multiple sclerosis. The original study of Allison and Millar in 1951 found a prevalence of 51/100,000 and mean annual incidence of 2.74/100,000/year. Subsequent studies in 1961, 1986, and 1996 suggested rising prevalence--80, 138, and 168.2/100,000, respectively.

METHODS

In 2004, we surveyed the North-East of Northern Ireland (population 160,446, area 2030 km(2)) using multiple sources of case ascertainment, all satisfying the Poser criteria for definite or probable multiple sclerosis (MS) or the McDonald criteria.

RESULTS

From a provisional list of 469 cases, 370 (123 males, 247 females) were identified. The prevalence was 230.6 per 100,000 (95% CI 207.0-255.4) with significantly higher prevalence in females (300.8/100,000) than males (157.0/100,000). Direct standardization to the 1961 Northern Ireland population reduced the overall prevalence rate to 200.5/100,000 (95% CI 193.2-208.0), in females to 270.2/100,000 (95% CI 258.8-282.4) and in males to 131.1/100,000 (95% CI 122.8-139.9). In 1996, incidence had risen to 9.3/100,000/year (14 cases in population of 151,000) with a higher incidence in females (10.3/100,000/year) than males (8.3/100,000/year).

CONCLUSIONS

Northern Ireland continues to have a rising prevalence of MS. The increase in incidence suggests a true increase in the disease.

Multiple Sclerosis in Isfahan, Iran

BACKGROUND

This survey was planned to study the prevalence and incidence of multiple sclerosis (MS) in Isfahan, Iran and to describe the clinical features of MS in general and in specific subgroups of patients (early-onset, late-onset, familial, and conjugal cases) and to compare our results with other reports.

METHODS

A cross-sectional study was conducted from April 5, 2003 to July 31, 2006. All patients known to have definite MS according to McDonald's criteria, alive, resident within Isfahan (a large province of Iran) and members of Isfahan MS Society (IMSS) were included in the study. Demographic and case-related information were recorded. A total number of 1718 definite MS patients (388 men and 1330 women) were identified from IMSS database.

RESULTS

The overall period prevalence of MS was 43.8/100,000. Among men the prevalence was 19.2 (95% CI: 17.4-21.2)/100,000 and among women 69.6 (95% CI: 66-73.4)/100,000. A female preponderance of 3.4 existed among these patients. In the year 2005, 143 new cases were diagnosed, resulting in an incidence rate of 3.64/100,000. The mean age of onset was 25.36 +/- 8.6 years (range 5-63 year), and mean duration of disease was 7.1 (+/-5.2) years for men and 6.7 (+/-5) years for women. Sensory and visual disturbances were the most common initial presentations with a prevalence of 51.7% and 47.5%, respectively. Cases identified include: early-onset MS (less than 15 years old at onset) with 87 cases (5%), late-onset MS (over 50 years old at onset) with 20 cases (1.1%), familial MS with 209 cases (12.2%), and conjugal MS with 6 cases (0.5%).

CONCLUSION

Isfahan is a medium- to high-risk area for MS, with prevalence higher than what has previously been reported, possibly because of an increase in the incidence rate. Clinical and demographic characteristics were similar to other reports; however, some differences existed.

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 cost of multiple sclerosis and the cost effectiveness of disease-modifying agents in its treatment

Multiple sclerosis (MS) is one of the most common causes of neurological disability in young and middle-aged adults. The full economic cost of MS is substantial given that MS patients experience a major perturbation in their daily activities and the disease affects mainly young people who are obliged to restrict their levels of economic activity, either temporarily or permanently. A positive relationship exists between the direct and indirect costs of MS and its severity. Cost variations between countries exist because of differences in the costs of inpatient care, the number of ambulatory visits, drug usage and the extent and type of informal care. The development and availability of new agents has been accompanied by an increased optimism that treatment regimens for MS would be more effective. However, doubts have been expressed about the effectiveness of these treatments, which have compounded the problems associated with estimating the relative cost effectiveness of such interventions. In addition, variations in the utility scores associated with disease categories, the impact of relapses and the resulting utility losses, plus the speed of disease progression have all contributed to the difficulty of estimating the quality-adjusted life year (QALY) losses for a patient experiencing MS. Differences between studies with respect to the costs associated with each disability level, the timescale of the disease and the period over which costs and QALYs are to be measured, and the perspective employed in relation to costing have also resulted in a wide range of estimates being produced for the cost effectiveness of interferons and glatiramer acetate in the management of MS. These range from situations of cost savings, to over $US1.6 million (euro1.85 million) per QALY gained. Recent cost-effectiveness studies have benefited from more relevant and up-to-date data relating to disease progression and have generally produced more favourable cost-effectiveness ratios. However, the lack of homogeneity in the design of the studies partly accounts for the extent of variation in the estimates of cost effectiveness, and the difficulty of arriving at a consensus. The UK Department of Health has introduced a scheme that provides disease-modifying agents in the National Health Service for those patients with clinically active relapsing disease. Patients are monitored annually and payments to manufacturers are dependent on outcomes achieved. This initiative, although not without its detractors, will hopefully enhance the quantity and quality of evidence on the impact of drugs on disease progression and address some of the current difficulties with estimating the relative cost effectiveness of disease-modifying drugs in the treatment of patients with MS.

Latitudinal variation in the prevalence of multiple sclerosis in Ireland, an effect of genetic diversity

BACKGROUND

Northern Ireland has a high and rising prevalence rate of multiple sclerosis (MS). The most recent survey in 1996 found a rate of 168.7/100 000. Recorded prevalence rates for the south of Ireland, including County Wexford, have been markedly lower and seemed to suggest the existence of a prevalence gradient within the island.

OBJECTIVES

To compare the prevalence of multiple sclerosis in Co. Wexford in the south east of Ireland and Co. Donegal in the north west, and to establish whether a variation in prevalence of MS exists within Ireland.

METHODS

Patients were referred from multiple sources. Review of clinical case records and/or patient examination confirmed the diagnosis.

RESULTS

In Co. Wexford, 126 patients were found to have clinically definite or probable multiple sclerosis with a prevalence rate of 120.7/100 000 (95% confidence intervals (CI) 100.6 to 143.8), which is similar to other areas of similar latitude within the British Isles. In Co. Donegal, 240 people had clinically definite or probable MS with a prevalence rate of 184.6/100 000 (95% CI 162.0 to 209.5). The difference in prevalence rates is statistically significant (Z = 3.94, p = <0.001).

CONCLUSION

There is a latitudinal variation in the prevalence rate of MS between the north and the south of Ireland. The increased prevalence of MS seen in Co. Wexford is likely to represent better case ascertainment and improved diagnostic accuracy rather than an actual increase in prevalence. The north/south variation in prevalence may represent a variation in the genetic predisposition to MS between the background populations of the two counties.

A questionnaire assessment of unmet needs for rehabilitation services and resources for people with multiple sclerosis: results of a pilot survey in five European countries. Needs Task group of MARCH (Multiple Sclerosis and Rehabilitation, Care and Health Services Research in Europe)

OBJECTIVE

To develop an international services and needs assessment instrument (SUN) for people with multiple sclerosis and their carers and to pilot this in different countries of the European Community.

DESIGN

Interview study of people with multiple sclerosis, their carers and nominated key professionals examining the unmet needs of patients and carers.

SETTING

Belgium, Estonia, Greece, Italy and the United Kingdom.

MAIN OUTCOME MEASURES

Needs assessment questionnaire.

RESULTS

The study comprised 137 people with multiple sclerosis, 125 carers and 111 professionals. Patients reported on average 2.9 unmet needs for themselves; their carers and professionals reported on average 2.4. Needs were categorized into seven broad categories. Due to difficulties experienced by the local researchers in distinguishing between needs and objectives a large proportion of needs had to be assigned to the 'other' category.

CONCLUSIONS

The SUN is a valuable and practicable tool for the identification of unmet needs for people with multiple sclerosis and their carers. Formal validation and reliability testing of the different language versions is recommended.

High incidence and prevalence of multiple sclerosis in south east Scotland: evidence of a genetic predisposition

OBJECTIVE

To determine the incidence and prevalence of multiple sclerosis in the Lothian and Border Health Board Regions of south east Scotland.

METHODS

Incidence study: all patients were identified in whom a diagnosis of Poser category probable or definite multiple sclerosis was made by a neurologist between 1992 and 1995. Prevalence study: all patients known to have multiple sclerosis who were alive and resident in the study area on 15 March 1995 were recorded.

RESULTS

The crude annual incidence rates of probable or definite multiple sclerosis per 100000 population were the highest ever reported: 12.2 (95% confidence interval (95% CI) 10.8-13.7) in the Lothian Region and 10.1 (95% CI 6.6-13.6) in the Border Region. A total of 1613 patients with multiple sclerosis were resident in the study area, giving standardised prevalence rates per 100000 population of 203 (95% CI 192-214) in the Lothian Region and 219 (95% CI 191-251) in the Border Region. Prevalent cases were more likely than expected to have a Scottish surname (risk ratio 1.24, 95% CI 1.14-1.34).

CONCLUSION

Orkney and Shetland were previously thought to have by far the highest prevalence of multiple sclerosis in the world: about double that found in England and Wales. However, the prevalence in south east Scotland is equally high, suggesting that the Scottish population as a whole has a genetic susceptibility to the disease, and undermining the hypothesis that patterns of infection specific to small sparsely populated island communities are important in the causation of multiple sclerosis.

Economic evaluation of multiple sclerosis in the UK, Germany and France

A cross-sectional cost-of-care study was performed to assess the economic burden of multiple sclerosis (MS) in France, Germany and the UK. Patients were stratified into 3 groups according to the Expanded Disability Severity Scale (EDSS): stages I, II and III, corresponding to mild (EDSS 1.0 to 3.5), moderate (EDSS 4.0 to 6.0) and severe (EDSS 6.5 to 8.0) MS, respectively. 90 patients with MS and 30 non-MS control patients were recruited in each country. Control patients were matched to the patients with MS on the basis of age and gender. Demographic, clinical and economic data during the 3-month period prior to entry were collected in patient interviews. Total costs included actual expenditures, such as direct medical and non-medical costs, as well as indirect costs. From the societal perspective, the total cost of MS for 3 months was estimated at 1,928 US dollars, 3,941 US dollars and 5,678 US dollars in France, 2,772 US dollars, 2,056 dollars and 5701dollars in Germany, and 5,125 US dollars, 6,751 US dollars and 14, 622 US dollars in the UK, for stage I, II and III patients, respectively. The major medical cost driver in the UK was outpatient consultations, whereas hospitalisations were the major component in Germany and France. The major cost in the UK arose from the dependence of patients with MS on caregivers, which caused high non-medical, societal costs compared with France and Germany. From both the societal and health insurance perspectives in each country, costs for control patients were lower than those for stage I MS patients. MS represents a major financial burden on the individual, the family, health services and society, and these costs increase with MS progression.

The prevalence of multiple sclerosis in the Leeds Health Authority

OBJECTIVES

To determine the prevalence of multiple sclerosis in the Leeds Health District.

METHODS

Multiple sources of case ascertainment were used-namely, neurology departments, hospital episode statistics, general practitioners, the Leeds branch of the Multiple Sclerosis Society, the West Yorkshire Multiple Sclerosis Therapy Centre, community physiotherapists and occupational therapists, the Leeds Wheelchair Centre, and the Young Disabled Unit. Data collection was from retrospective analysis of hospital and primary care case records. A population based incidence register was established by prospectively registering all new patients with diagnoses of multiple sclerosis.

RESULTS

On prevalence day, 30 April 1996, 712 people with multiple sclerosis were identified living in Leeds (population 732,061), giving a prevalence of 97/10(5). The prevalence for definite and probable multiple sclerosis was 84/10(5), and for suspected multiple sclerosis it was 13/10(5). The sex ratio of prevalent people with multiple sclerosis was 2.79 to 1 women to men. The mean age of prevalent cases was 51 years, the mean age at symptom onset was 34 years, and the mean duration of disease was 16 years. Forty cases were prospectively reported as incident cases from 1 November 1995 to 1 February 1996.

CONCLUSIONS

The prevalence of multiple sclerosis in Leeds was found to be similar to that in the south of the United Kingdom but lower than that in Scotland. There is no evidence of a latitudinal gradient of increasing prevalence of multiple sclerosis from the south to the north of England.

Multiple sclerosis in Fife

Patients in Fife with multiple sclerosis were identified from three sources: a postal questionnaire to all general practices in Fife, hospital discharge data, rehabilitation service database. A total of 508 patients were identified in a population of 354,273 giving a crude prevalence rate of 143/100,000. The Standardised Prevalence Rate was 178/100,000. The sex ratio was 2.43 females to males. The prevalence was higher than identified in southern parts of the United Kingdom and similar to northern Scotland. A total of 200 (40%) cases were identified as having relapsing-remitting disease and of these 151 were ambulant, making them eligible for treatment with interferon beta-lb under current licensing criteria. Only 90 (60%) of the 151 currently eligible for the drug were under the care of a specialist and almost half the practices felt that they would change their referring habits. These factors may have implications for the workload of specialist clinics.

Role of myelin basic protein and proteolipid protein genes in multiple sclerosis: single strand conformation polymorphism analysis of the human sequences

Susceptibility to multiple sclerosis (MS) is widely held to have a strong genetic component. While the identities of genes conferring susceptibility are currently unknown, possible candidates include those genes coding for proteins which function in central nervous system (CNS) myelin. Two such genes are the human myelin basic protein (MBP) and proteolipid protein (PLP) genes, whose products make up approximately 80% of the total protein in CNS myelin. The association of a variable number tandem repeat (VNTR) 5' to the human MBP gene with MS has been the subject of conflicting reports. Here we test the hypothesis that mutations in the human MBP and PLP genes might be associated with MS by examining the entire expressed sequence of both genes by single strand conformation polymorphism (SSCP) analysis, using a panel of 71 MS patients and 71 controls. We have also re-examined the VNTR region in patients and controls. Three base changes were found in the human PLP gene and nine base changes in the human MBP gene; these were essentially equally distributed between patients and controls. No preferential distribution of various alleles of the VNTR between patients and controls was found. Although intronic and regulatory regions have not been examined, it would appear unlikely that mutations in these genes coding for the two major CNS myelin proteins contribute significantly to genetic susceptibility to MS.

Epidemiology and estimated population burden of selected autoimmune diseases in the United States

Autoimmune diseases cause significant and chronic morbidity and disability. The actual number of persons in the United States that are affected by autoimmune diseases and the resultant magnitude of their impact on the public's health are limited to a few specific diseases. In order to understand the clinical, public health and economic importance of these diseases it is necessary to have estimates of incidence and prevalence rates in the population. In this analysis, we estimate the number of persons affected by 24 autoimmune diseases in the United States by applying mean weighted prevalence and incidence rates obtained from published articles to U. S. Census data. The study was restricted to 24 autoimmune predefined diseases for which there was direct or indirect evidence for autoimmune pathogenesis. Subsequently, we used computerized search software and ancestry searching (bibliographies) to conduct a comprehensive search of articles published from 1965 to the present. Eligible studies included those which adhered to standard disease definitions and which included population-based estimates of incidence or prevalence rates. Mean weighted incidence and prevalence rates were calculated from eligible published studies with greater weight proportionately given to larger studies. The mean rates were then applied to the U.S. Census population figures to estimate the number of persons currently afflicted with each disease and the number of new cases occurring each year in the United States. Only U.S. and European studies were used to estimate prevalence and incidence rates when there were at least six eligible studies available for a disease. When there were fewer than six studies, all available studies were included, regardless of country of origin. The number of eligible incidence and prevalence studies found in the literature varied considerably between the 24 autoimmune diseases selected. The largest number of eligible prevalence studies were conducted on multiple sclerosis (MS), rheumatoid arthritis, and systemic lupus erythematosus (SLE) (>/=23), followed by insulin-dependent diabetes (IDDM), myasthenia gravis, primary biliary cirrhosis, and scleroderma (>/=7). There were only one to four eligible studies done on 11 other diseases, and no prevalence studies on 6 diseases. Incidence studies were less frequent but the largest number of studies were conducted on IDDM (n = 37) and MS (n = 28), followed by Graves' disease/hyperthyroidism, glomerulonephritis, primary biliary cirrhosis, rheumatic fever, rheumatoid arthritis, scleroderma, and SLE (>/=9). On the other 11 diseases, there were one to six eligible studies, and no studies on 5 diseases. There were no eligible incidence or prevalence studies on Goodpasture's syndrome, idiopathic thrombocytopenia purpura, or relapsing polychondritis. Overall we estimate that 8,511,845 persons in the United States or approximately 1 in 31 Americans are currently afflicted with one of these autoimmune diseases. The diseases with the highest prevalence rates were Graves'/hyperthyroidism, IDDM, pernicious anemia, rheumatoid arthritis, thyroiditis, and vitiligo, comprising an estimated 7,939, 280 people or 93% of the total number estimated. Glomerulonephritis, MS, and SLE added an estimated 323,232 people. The prevalence of the other diseases reviewed were rare, less than 5.14/100,000. Most diseases were more common in women. From the incidence data we estimate that 237,203 Americans will develop an autoimmune disease in 1996 and that approximately 1,186,015 new cases of these autoimmune diseases occur in the United States every 5 years. Women were at 2.7 times greater risk than men to acquire an autoimmune disease. After reviewing the medical literature for incidence and prevalence rates of 24 autoimmune diseases, we conclude that many autoimmune diseases are infrequently studied by epidemiologists. As a result the total burden of disease may be an underestimate. (ABSTRACT TRUNCATED)

Economic consequences of multiple sclerosis for Canadians

OBJECTIVES

To estimate the total costs of multiple sclerosis (MS) for all Canadians in 1994.

METHODS

Prevalence-based study estimating disease-related societal costs for Canadians with MS in 1994. The human capital approach was used to estimate the value of lost productivity due to illness. Two components were revealed: first, direct costs, in terms of expenditures on hospital care, other institutions, physician services, other health professionals, drugs, and other expenditures; and second, indirect costs, in terms of lost productivity due to premature mortality and disability.

RESULTS

The total costs of MS for Canadians were $502.3 million in 1994, with direct and indirect cost components at $188.6 million and $313.7 million, respectively.

CONCLUSIONS

This study highlights the scope and magnitude of the economic consequences of MS for Canadians. The costs calculated may be used to provide guidance in the setting of national priorities for research and prevention activities.

Multiple sclerosis in the Turkish- and Greek-speaking communities of Cyprus. A United Nations (UNHCR) Bicommunal Project

A United Nations (UNHCR)-sponsored study has been undertaken, involving neurologists from the Turkish-speaking northern and Greek-speaking southern communities of Cyprus, to ascertain the prevalence of multiple sclerosis (MS) and to bring the medical personnel of the two communities to work together. The Turkish community includes both Turkish Cypriots and, since 1974, a big influx of immigrants from Turkey. The prevalence of MS among Turkish Cypriot men was significantly higher than in Turkish Cypriot women and was as high as has been found in men in recent studies in Northern Europe. It was also significantly higher than among Greek Cypriot men. The prevalence in Turkish Cypriot women was not significantly different to that found in Greek Cypriot women. Among the immigrants from mainland Turkey MS prevalence was significantly less for both men and women than among the Turkish Cypriots. In the Greek-speaking metropolitan area of Nicosia the prevalence of MS was 51 per 100,000, (males 43, females 59). The overall MS prevalence in four areas studied in Greek-speaking Cyprus, including three previously studied, was 42 per 100,000, (males 39, females 46 per 100,000).

Analysis of polymorphisms of the 2',3'-cyclic nucleotide-3'-phosphodiesterase gene in patients with multiple sclerosis

Susceptibility to multiple sclerosis (MS) is widely held to have a genetic component. Possible candidate genes conferring this susceptibility include those coding for proteins specific to central nervous system (CNS) myelin. 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) is an enzyme found at high concentrations in CNS myelin, however its function is unknown. The amino acid sequence of CNPase shows a C-terminal motif characteristic of proteins involved in signal transduction pathways, suggesting a key role in myelin function. We have analysed the entire expressed sequence of the human CNPase gene in patients with multiple sclerosis and in healthy controls using single strand conformation polymorphism (SSCP) analysis. Nine previously undescribed mutations were detected, most of these occurred with equal frequency in both groups. However, a T-->C transition at nucleotide position 4306 in the region of the gene coding for the 3' untranslated region of the mature mRNA was found in a homozygous form in two out of 54 patients but in none of 100 controls. While the significance of this is unclear, it would appear unlikely that mutations in the expressed regions of the human CPNase gene contribute to genetic susceptibility to MS in the majority of sufferers.

Prevalence of multiple sclerosis in Rochdale

The prevalence of multiple sclerosis in the Rochdale Metropolitan Borough in the north east of Greater Manchester has been established. Case ascertainment was partly prospective via a neurological register from 1979 and by contact with general practitioners, therapists, and social services. On prevalence day, 1 January 1989, 254 patients with multiple sclerosis were living in Rochdale. The overall prevalence was 122/100,000 population and 96/100,000 population for probable cases only. The peak rate for women aged 35 to 44 years was 437/100,000 population and for men aged 45 to 54 years 221/100,000. Familial multiple sclerosis was present in 10.8% of families. In this, the first study in north west England, the prevalence of multiple sclerosis in Rochdale is similar to that in southern England and Wales but lower than that in Scotland.

Epidemiology of multiple sclerosis

The inhomogeneous distribution of MS may represent an important clue about the cause of the disease. The prevalence of MS appears to be increasing in many regions of the world, although it is likely that in a majority of regions surveyed, this increase is attributable to differences in ascertainment over the relatively short period that MS has been surveyed worldwide, which is almost exclusively the last 50 years. MS occurs most frequently in regions populated by northern Europeans, and in these areas, it is much more common in the northern European population than in the indigenous populations. MS occurs in relatives of MS patients at a rate 10- to 50-fold greater than in the general population. On average, the absolute risk to a first-degree relative of an MS patient is 2% to 5%, depending on the exact degree of relatedness. Although the mode of transmission is not certain, a multigenic pattern best fits the observed pattern of transmission. A majority of monozygotic twins are discordant for MS, indicating that a major component of MS susceptibility is environmentally determined, although recent observations in adopted relatives suggest that this risk is not transmissible. Rare epidemics of MS involving small numbers of individuals in geographically isolated regions have been reported. A number of migrant studies suggest that the risk of acquiring MS may be altered by migration, although some also support genetic factors. Analytic approaches to address the role of various risk factors include ecologic studies, case-control studies, and cohort studies. Ecologic studies are best suited for addressing risk factors that influence overall population risk, whereas case-control studies are best suited for addressing risk factors that pertain to individuals within a population. If a risk factor is distributed homogeneously in a given population, a case-control study is insensitive to its effect. Improved methodology to diminish the biases inherent in case-control studies and identification of other important risk factors from basic scientific studies undoubtedly will be important for analytic epidemiologic studies of the future. Furthermore, analysis of highly informative populations, such as discordant identical twins and adoptive siblings of MS patients, likely will improve the specificity of case-control studies by minimizing the vast number of potential differences between cases and controls.

Single strand conformation analysis of two genes contained within the first intron of the neurofibromatosis type I gene in patients with multiple sclerosis

Single strand conformation analysis has become the most widely used technique to screen large numbers of DNA samples for unknown mutations which may contribute to genetic susceptibility to disease. The method relies on the electrophoretic migration of a single strand of nucleic acid in a polyacrylamide gel being dependent on its conformation which is in turn dependent on its sequence. We have examined two closely related genes present in the first intron of the neurofibromatosis type I gene--the oligodendrocyte myelin glycoprotein (OMGP) gene and the ecotropic viral integration 2A (EVI2A) gene--in 36 patients with multiple sclerosis (MS) and 36 healthy controls. A single mutation was found in the OMGP gene which resulted in an amino-acid change of glycine to aspartic acid. This occurred in identical proportions (16.6%) in MS patients and controls. Two rare mutations were found in the EVI2A gene, one resulting in an arginine substituting for a glutamine (one control and one patient), the other in the replacement of a glycine with serine (one control only). A third common polymorphism was seen in 5'-untranslated region of the EVI2A gene, with 65% of patients and controls showing a T-->C transition in either a heterozygous or a homozygous form. This makes it unlikely that either of these genes is involved in genetic susceptibility to MS, but regions of these genes outside of the exonic sequences have not been examined.

Genetic susceptibility to multiple sclerosis in a Shanghai Chinese population. The role of the HLA class II genes

The association of MS with the HLA class II loci DR and DQ was investigated in subjects of Shanghai Chinese and British Caucasian origin. Our aim was to determine whether common alleles predispose to the disease in both races. In the Caucasian population MS was significantly positively associated with the putative haplotype DRB1*1501, DQA1*0102, DQB1*0602. In contrast, HLA class II alleles were not found to predispose to the disease in the Shanghai Chinese, suggesting that this haplotype is unlikely to be a universal susceptibility determinant. The absence of a disease association with the HLA-DR and -DQ genes in the Chinese population has a number of possible explanations. Our study suggests that other genetic and/or environmental components may be more important in determining susceptibility to MS in this race.

Surveying multiple sclerosis in the United Kingdom

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A prevalence survey of multiple sclerosis in Sussex

A first survey of the Brighton and Mid-Downs health districts in Sussex showed a prevalence of multiple sclerosis of 111 per 100,000 (95% confidence interval (95% CI) 103-120) in a population of 596,594 on prevalence day, 1 July 1991. Cases were notified by multiple sources and to maximise case notification patients were not contacted. Cases were classified by hospital and family practitioner notes. The Poser criteria were used for classification. These criteria are precise and exclude cases of isolated spinal cord syndrome. The Allison and Millar criteria used in the surveys in Scotland may lack specificity and it is concluded that the high prevalence of multiple sclerosis in Scotland needs to be reassessed with the more precise criteria. Until this is done, the latitude effect within the United Kingdom remains not proved.

Multiple sclerosis in island populations: prevalence in the Bailiwicks of Guernsey and Jersey

The aim of this study was to establish for the first time the prevalence of multiple sclerosis in the Bailiwicks of Guernsey and Jersey, as representing the most southerly part of the British Isles. All patients with multiple sclerosis in the Channel Islands resident on prevalence day were identified by contacting all medical practices, Multiple Sclerosis, and Action Research for Multiple Sclerosis societies by letter and visits. The crude overall prevalence rates were 113/100,000 (95% confidence interval (95% CI) 90.3-135.7) and 86.7/100,000 (95% CI 63.3-110.0) for the Bailiwicks of Jersey and Guernsey respectively. When standardised to the age and sex structure of a previously reported Northern Ireland population the standardised prevalence ratios were 120.2/100,000 (95% CI 96.0-144.3) for Jersey and 95.6/100,000 (95% CI 69.9-121.3) for the Bailiwick of Guernsey. When compared with recent studies in the northern United Kingdom the prevalence rates for multiple sclerosis in the Channel Islands lend some support to the proposed latitudinal gradient in the British Isles although the standardised prevalence ratio in the Bailiwick of Jersey is similar to those found in recent studies of southern Britain. The standardised prevalence rates of probable and definite multiple sclerosis for the male populations were 37.3/100,000 (95% CI 17.9-56.7) for the Bailiwick of Guernsey and 45.5/100,000 (95% CI 26.3-64.7) for the Bailiwick of Jersey whereas the standardised prevalence rates for the female populations were 97.5/100,000 (95% CI 73.9-143.5) and 139.5/100,000 (95% CI 112.6-181.2) respectively. Thus there is a striking and unexplained 43% higher prevalence of probable and definite multiple sclerosis in the female population of Jersey compared with that of the Bailiwick of Guernsey. This seems to be due to an unusually low prevalence of the disease among the female population of the Bailiwick of Guernsey compared with that of the United Kingdom mainland.