Multiple sclerosis in Vest-Agder County, Norway

Vatne A., Mygland Å., Ljøstad U. Multiple sclerosis in Vest‐Agder county, Norway.
Acta Neurol Scand: 2011: 123: 396–399.
© 2010 John Wiley & Sons A/S. Objective – To examine multiple sclerosis (MS) prevalence, rate of immunomodulatory treatment and frequency of Borrelia Burgordorferi (Bb) antibodies in Vest‐Agder, Norway. Materials and methods – Patients in the period 1996–2006 who met the Poser criteria for definitive or probable MS were included. Clinical and demographical data, and presence of Bb antibodies were registered. Results – A total of 295 patients were identified. The crude prevalence was 180 per 100,000 population (95% CI = 160.9–218.0), age‐adjusted prevalence was 186 per 100,000 population (95% CI = 166.3–225.3). The age‐adjusted incidence rates were 7.5 and 8.0 for 1996–2000 and 2001–2006, respectively. Thirty‐eight per cent were treated with immunomodulatory agents when compared to 28% in the rest of the country. Bb serum antibodies were detected in 7% of patients with MS. Conclusions – Vest‐Agder county has the highest prevalence of MS reported in Norway, and a high treatment rate. Bb antibodies were not more prevalent than in healthy individuals.     

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.     

Epidemiologic trends in multiple sclerosis in M?re and Romsdal, Norway: a prevalence/incidence study in a stable population

The western part of Norway has been a low-to medium-frequency area for multiple sclerosis (MS). The prevalence of definite/probable MS on January 1, 1961, was 24.3/100,000 in the county of M?re and Romsdal, western Norway. Based on the same diagnostic criteria, the prevalence of definite/probable MS increased to 75.4/100,000 on January 1, 1985. The average annual incidence rate increased from 1.94/100,000 in the period 1950-1954 to 3.78/100,000 from 1975-1979. Remitting MS in the younger age groups of both sexes increased the most. We consider this increase of MS to be due to alteration in exogenous factors as variation in genetic susceptibility cannot account for the increase in the stable western Norwegian population. The rise in prevalence/incidence over the last 20 to 25 years in western Norway supports the theory that MS is a disease influenced by exogenous factors that show variation over time.     

Epidemiology of multiple sclerosis in the county of Vestfold, eastern Norway: incidence and prevalence calculations

The county of Vestfold in the South-eastern part of Norway has undergone two incidence and prevalence surveys on multiple sclerosis. The prevalence of definite/probable MS on January 1.1963 was 61.6/100000. Based on the same diagnostic criteria, the present study reports a slight increase in prevalence to 86.4/100000 on January 1st 1983. The average annual incidence was calculated for 5 years periods from 1953 to 1983. The time periods 1953–1962 and 1973–1977 showed age-adjusted incidence rates between 4.50 and 5.49/100000 while the 10–year period 1963–1972 showed significantly lower rates. The fluctuating pattern of MS incidence and prevalence over time supports the view that MS is not a stable disease, and that exogenous factors are influencing the disease pattern.     

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.     

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

OBJECTIVE: To determine the incidence and prevalence rates of multiple sclerosis (MS) and their temporal profiles over the last 30 years in the province of Padova (northeast Italy). BACKGROUND: In the early 1970s an epidemiological survey in the province of Padova showed a MS prevalence and incidence of 16/100 000 and 0.9/100 000 population, respectively; these figures are much lower than current estimates in other regions of Italy and Central Europe. METHODS: The population of the study area was approximately 820 000 (422 028 women, 398 290 men) in the 1991 census. All possible sources of case collection were used, but only clinically definite/probable and laboratory-supported definite/probable MS were considered in the analysis of incidence and prevalence trends from 1971 to 1999. RESULTS: On 31 December 1999, the crude prevalence rate was 80.5/100 000 (95% CI 70.3-90.7); prevalence was higher in women (111.1/100 000; 95% CI 99.0-123.1) than in men (49.7/100 000; 95% CI 41.3-58.1). This difference was significant (F/M = 2.43; z = 10.1, P < 0,00001); a rate adjusted for the European population was 81.4/100 000. On 31 December 1980 and on 31 December 1990 the estimated prevalence rates were 18/100 000 and 45.7/100 000, respectively. Thus, a fivefold increase in prevalence was observed from the 1970s. The mean annual incidence was 2.2/100 000 in the period 1980-89, 3.9 in the period 1990-94 and 4.2 in the period 1995 99. Thus, incidence increased more than fourfold from the 1970s through 1994 and remained quite stable in the last several years. Mean age at onset was 31.3 +/- 9.88 years. Mean diagnostic latency decreased significantly from 49.2 +/- 44.5 months in 1985 to 23.0 +/- 30.3 months in 1990, 12.9 +/- 15.61 in 1995 and 5.3 +/- 4.7 in 1999. CONCLUSIONS: The actual prevalence (80.5/100 000) and incidence (4.2/100 000) of MS in the province of Padova agree with the most recent epidemiological estimates/trends observed in other Italian and European areas, except for Sardinia and Scotland. The increase in both incidence and prevalence rates observed in much of this region over the last 30 years parallels the introduction of more sensitive diagnostic techniques and a highly significant decrease in diagnostic latency. These findings probably do not support a real increase in the frequency of MS in northeast Italy because recent estimates of incidence have increased only slightly (3.9 to 4.2, which is < 10% in five years) and increase in the prevalence rate was almost completely due to the accumulation of new incidence cases.     

Prevalence of Parkinson's disease and atypical parkinsonian syndromes in a rural Japanese district

Osaki Y, Morita Y, Kuwahara T, Miyano I, Doi Y. Prevalence of Parkinson’s disease and atypical parkinsonian syndromes in a rural Japanese district.
Acta Neurol Scand: 2011: 124: 182–187.
© 2010 John Wiley & Sons A/S. Objectives – To investigate the prevalence of Parkinson’s disease (PD) and atypical parkinsonian syndromes (APS) in a rural Japanese district. Method – Collaboration with the medical institutions, the long‐term care insurance system facilities, and the public health office. Results – The crude prevalence rates were 175 per 100 000 (95% CI: 143–206) for PD, 18 (8–28) for progressive supranuclear palsy, 17 (7–26) for multiple system atrophy (MSA), and 9 (2–16) for corticobasal degeneration. The age‐adjusted prevalence rates were 109 per 100 000 (88–134), 10 (2–17), 13 (4–21), and 6 (0–12), for each condition. There was a preponderance of women with PD and of men with APS. Nine of the 116 PD patients and 7 of the 29 APS patients were newly diagnosed in this study. Conclusions – There are high prevalence rates for PD and APS and suboptimal recognition of APS. This is the first epidemiological prevalence study of MSA from Japan.     

Epidemiology of multiple sclerosis in London and Middlesex County, Ontario, Canada

A case-controlled epidemiologic study of multiple sclerosis (MS) was carried out in London, Ontario, and its surrounding Middlesex County for the period 1974-1983. The prevalence rates for clinically definite/probable MS on January 1, 1984 were 94/100,000 for the city and 91/100,000 for the county. The estimated annual incidence rate for the decade 1974-83 was 3.4/100,000. The female-to-male sex ratio was 2.5:1. A familial history of MS was recorded in 14.4% of close relatives and a total of 17% when distant relatives are included. The MS group is predominantly of British (70%) and European (23%) origin. The urban-rural residence pattern analysis indicates no significant regional influence on the risk of developing MS.     

Multiple sclerosis in Oslo, Norway: prevalence on 1 January 1995 and incidence over a 25-year period

The Oslo Multiple Sclerosis (MS) Registry was established in 1990, and this is the first report on the prevalence and incidence of MS in the city of Oslo, Norway. The prevalence rate of definite MS on 1 January 1995 was 120.4/10(5). Inclusion of patients of native Norwegian ancestry only and exclusion of non-Norwegian immigrants yielded a prevalence rate of 136.0/10(5). A similar prevalence rate (136.5/10(5)) was found when patients and immigrants from the other Nordic countries (Finland, Sweden, Denmark) were included. Segregation of the native Norwegian patients according to the counties where they were born showed no significant differences except for a disproportionate increase of patients born in the inland county of Oppland. A total of 794 cases were resident in Oslo at the time of a diagnosis of definite MS in the period 1972-99. The crude average annual incidence rate for each 5-year period, between 1972 and 1996, increased significantly from 3.7/10(5) in the 1972-76 to 8.7/10(5) in the 1992-96 period. The increase was more marked in relapsing-remitting (RR) than in primary progressive disease and in female cases.     

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.     

Evaluating the use and limitations of the Danish National Patient Register in register-based research using an example of multiple sclerosis

Mason K, Thygesen LC, Stenager E, Brønnum‐Hansen H, Koch‐Henriksen N. Evaluating the use and limitations of the Danish National Patient Register in register‐based research using an example of multiple sclerosis.
Acta Neurol Scand: 2012: 125: 213–217.
© 2011 John Wiley & Sons A/S. Background – The Danish National Patient Register, Landspatientregistret (LPR), is a register of all hospital discharges and outpatient treatments in Denmark. Aims – It is increasingly used in research so it is important to understand to what extent this can be used as an accurate source of information. Virtually all patients in Denmark with multiple sclerosis (MS) are reported to the Combined MS Registry (DMSR), so this was used as the standard which the LPR was compared against. Methods – All residents of Denmark are assigned a unique Civil Register (CPR) number; this was used to compare data between registers. The LPR completeness was estimated by the proportion of cases from the DMSR that could be retrieved from the LPR. The LPR validity was estimated by the proportion of cases, listed in the LPR and DMSR, in whom the MS diagnosis could be confirmed as definite/probable/possible by the DMSR. Results – We found that 86.9% of those who were DMSR listed with an approved MS diagnosis were also listed in the LPR with a MS diagnosis. The diagnosis was valid in 96.3% of patients listed in the LPR when compared against the DMSR. Conclusions – The low completeness reduces the usefulness of the LPR in epidemiological MS research, in particular incidence studies. The study also found that the completeness of the LPR could be increased to 92.8% by including LPR records from other departments in addition, but this reduced the validity of the LPR to 95.1%. However, these results cannot uncritically be applied to registration of other diseases in the LPR.     

Validation of the multiple sclerosis international quality of life (MusiQoL) questionnaire in Norwegian patients

Beiske AG, Baumstarck K, Nilsen RM, Simeoni M‐C. Validation of the multiple sclerosis international quality of life (MusiQoL) questionnaire in Norwegian patients.
Acta Neurol Scand: 2012: 125: 171–179.
© 2011 John Wiley & Sons A/S. Objectives – To assess the validity and reliability of the multidimensional, self‐administered Multiple Sclerosis International Quality of Life (MusiQoL) questionnaire, previously validated in a large international sample, in Norwegian patients. Patients and methods – Patients with different types and severities of multiple sclerosis (MS) were recruited from a single MS centre in Norway. All patients completed the MusiQoL and Short Form‐36 (SF‐36) QoL questionnaires at baseline and a mean of 21 (SD 7) days later. A neurologist collected sociodemographic, MS history and outcome data. Construct validity, internal consistency, reproducibility and external consistency were tested. Results – One hundred and four patients were evaluated. Construct validity was confirmed in terms of satisfactory item internal consistency correlations in eight of nine MusiQoL dimensions (Spearman’s correlation: 0.34–0.79) and scaling success of item discriminant validity (75.0–100%). All dimensions of the MusiQoL questionnaire exhibited satisfactory internal consistency (Cronbach’s alpha: 0.44–0.87) and reproducibility (intraclass correlation coefficients: 0.36–0.86). External validity testing showed that the global MusiQoL score correlated significantly with all but one individual SF‐36 dimension score (Spearman’s correlation: 0.29–0.56). Conclusions – These results demonstrate that the Norwegian‐language version of the MusiQoL questionnaire is a valid and reliable instrument for assessing health‐related QoL in Norwegian patients with MS.     

Disability and mortality in multiple sclerosis in Western Norway

Introduction – Continued studies of frequency trends in carefully selected sites around the world can provide clues to the cause of multiple sclerosis (MS). Material and methods – Based on information from three different, semi-independant sources of information, we have examined the temporal trends in the average annual age-adjusted rates of disability pension incidence, mortality, and incidence of MS from 1966 to 1991 in More and Romsdal County, Norway. Results – The average annual age-adjusted disability pension incidence rates (1966–68 = 3.62/100,000; 1990–91 = 7.33/100,000), the mortality rates (1966–68=0.91/100,000; 1990–91 = 1.88/100,000), and the incidence rates (1966–68 = 4.22/100,000; 1990–91 = 5.02/100,000) all showed a statistically significant increase. The difference in the development of MS-specific disability pension prevalence rates in the county compared to the nation is notable. Conclusions – We consider that the increase in disability pension incidence, mortality, and incidence of MS is of biological significance. Thus three different sources of information corroborate corresponding trends indicating that better case ascertainment and improved diagnostic facilities only partially can explain the reported MS increase in western Norway.     

The risk of motor neurone disease and multiple sclerosis is different in Estonians and Russians. Data from South Estonia

Epidemiological studies were performed in South Estonia to establish the prevalence rate of multiple sclerosis (MS) and motor neurone disease (MND). The case finding method included information from the hospital records of the central hospital in the region-the University Hospital (for MS from 1942 to 1989), from all neurologists in the region, from the Estonian MS Society and Association of Muscular Disorders, and from nursing homes in the region. The prevalence day was 31 December 1989. MND incidence was established for the period of 1986-1995. The results demonstrated high prevalence rates of MS among native Estonians (55.3 per 100 000), somewhat lower prevalence among native-born representatives of other nationalities (43.6 per 100 000) and the lowest prevalence rate of MS among non-Estonian immigrants (26.6 per 100 000). The differences were not statistically significant. The results for MND demonstrated the opposite pattern. The mean annual incidence rate of MND for 10 years was statistically significantly higher among people of other nationalities (2.5 per 100 000) and Russians (2.6 per 100 000), and lower in native-born Estonians (1.1 per 100 000). No differences in health care or clinical picture were established. The reasons for the demonstrated differences in MND incidence remain unclear.     

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

Hawkes CH, Chawda S, Derakshani S, Muhammed N, Visentin E, Boniface D. MRI and visual‐evoked potentials in partners of multiple sclerosis patients.
Acta Neurol Scand: 2012: 125: 424–430.
© 2011 John Wiley & Sons A/S. 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.     

Prevalence of multiple sclerosis in Västerbotten County in northern Sweden

Objective – To estimate the prevalence and clinical characteristics of multiple sclerosis (MS) in Västerbotten County in northern Sweden. Methods–Individuals with MS were identified from several sources. A follow‐up interview and/or examination was performed in 94% of cases still living in the area during 1997–99. Onset adjusted prevalence and a definition of onset symptoms were applied. Results– A total of 313 cases were identified, resulting in an onset adjusted crude prevalence of MS for January 1990 of 125/10⁵ (95% confidence interval (CI): 112–140). Female predominance was evident (163/10⁵ (95% CI: 142–187) vs 86/10⁵ (95% CI: 71–104)). Diagnostic coding registers were the most important source for identification of cases. Conclusions– The crude prevalence of MS in Västerbotten was higher than previous reports from other major areas in Scandinavia. The adjusted prevalence was significantly higher when compared with a previous study from Göteborg, south‐western Sweden. The methodology used in this study gives a high degree of case ascertainment and increases the comparability of multiple sclerosis epidemiological studies.     

Prevalence of multiple sclerosis in Barrhead County, Alberta, Canada.

A prevalence study of multiple sclerosis (MS) was carried out in the town of Barrhead and surrounding county of Barrhead, in Alberta, Canada. The prevalence rate for clinically probable/definite multiple sclerosis on January 1, 1990 was 196/100,000. The average annual incidence rates for patients living in the area at onset were 1.31/100,000 for 1950-59, 4.97/100,000 for 1960-69, 3.77/100,000 for 1970-79, and 4.22/100,000 for 1980-89. Fifty percent of the patients were relapsing-remitting. Sixty percent were still walking without assistance. The female-to-male ratio was 1:1. Mean current age, age at onset and duration of illness were 49, 27 and 22 years respectively. The majority of patients (40%) experienced multiple symptom onset. Fifty percent were of single ethnic origin (either British or German); the rest were predominantly North European combinations. Forty percent of patients reported another MS relative. MS had affected the work status of 60% of the patients, 15% of whom were confined to an extended care centre.     

The influence of warm versus cold climate on the effect of physiotherapy in multiple sclerosis

Smedal T, Myhr K‐M, Aarseth JH, Gjelsvik B, Beiske AG, Glad SB, Strand LI. The influence of warm versus cold climate on the effect of physiotherapy in multiple sclerosis.
Acta Neurol Scand: 2011: 124: 45–52.
© 2010 John Wiley & Sons A/S. Objective – To compare the effect of inpatient physiotherapy in a warm versus cold climate in short‐ and long‐term perspectives. Methods – Sixty multiple sclerosis (MS) patients with gait problems, without heat intolerance, were included in a randomized cross‐over study of 4‐week inpatient physiotherapy in warm (Spain) and cold (Norway) climate. The primary outcome, 6‐min walk test (6MWT), and secondary physical performance and self‐reported measures were scored at screening, baseline, after treatment and at 3 and 6 months of follow‐up. Treatment effects were analysed by mixed models. Results – After treatment, the mean walking distance had increased by 70 m in Spain and 49 m in Norway (P = 0.060). Improvement in favour of warm climate was demonstrated at 6 months of follow‐up, 43 m (Spain) compared to 20 m (Norway) (P = 0.048). The patients reported less exertion after walking (6MWT) in favour of treatment in Spain at all time points (P < 0.05). No significant differences in change were detected for the other physical performance measures. Most self‐reported measures showed more improvement after treatment in Spain, but these improvements were not sustained at follow‐up. Conclusion – The results indicate that MS patients without heat intolerance have additional benefits from physiotherapy in a warm climate.     

Five‐year incidence of surgery for idiopathic normal pressure hydrocephalus in Norway

Objectives – We have previously determined the incidence and prevalence of idiopathic normal pressure hydrocephalus (iNPH) in the county of Vestfold in Norway. This study aimed at determining the incidence of surgeries for iNPH. Materials and methods – Information about age, sex, operation year and operation type was collected retrospectively for all patients hospitalized from 2002 to 2006 with any diagnosis of iNPH and operated with insertion of a ventriculo‐peritoneal or ventriculoatrial shunt system, or with endoscopic third ventriculostomy in any of Norway’s five regional neurosurgical centers. Results – Two hundred fifty‐two patients were operated during the 5‐year period, making the total incidence 1.09/100,000/year. The yearly incidence ranged from a minimum of 0.84/100,000 in 2006 to a maximum of 1.47/100,000 in 2004. The incidence was highest in the age group 70–79 years. There were little regional differences regarding incidence, sex, and age and operation type. Conclusions – The data suggest that too few patients are being offered surgical treatment for iNPH in Norway.     

Comparison of carbamazepine rash in multiple sclerosis and epilepsy

Shirzadi M, Alvestad S, Hovdal H, Espeset K, Lydersen S, Brodtkorb E. Comparison of carbamazepine rash in multiple sclerosis and epilepsy.
Acta Neurol Scand: 2012: 125: 60–63.
© 2011 John Wiley & Sons A/S. Objectives – Studies on the comorbidity of multiple sclerosis (MS) and allergic disorders have shown conflicting results. Carbamazepine (CBZ) is widely used in MS to control pain. We have compared the incidence of rash from CBZ use in MS and epilepsy. Materials and Methods – Consecutive adult patients with MS and epilepsy were studied retrospectively. A detailed survey of medical records concerning CBZ treatment was performed. Results – A total of 495 patients with epilepsy and 442 patients with MS were included. Sixty‐five per cent of patients with epilepsy and 20% of patients with MS had used CBZ. In CBZ‐exposed patients, rash occurred in 15/89 (17%) in MS and in 43/323 (13%) in epilepsy, a difference which was not significant. Women below 50 years experienced more skin reactions than older women and men. The unadjusted odds ratio (OR) for rash in the MS vs epilepsy group was 1.32 (CI 0.70–2.51, P = 0.40). Adjusting groups for gender and age reduced the OR to 1.11 (CI 0.56–2.19, P = 0.76). Conclusion – Compared with epilepsy, which is only rarely caused by immunological mechanisms, the autoimmune disorder MS was not associated with a different occurrence of CBZ skin reactions. The trend towards an increased occurrence of rashes in MS can partly be explained by a higher predisposition to CBZ rash in women of fertile age.