The relation of ultraviolet radiation and multiple sclerosis in Newfoundland.

BACKGROUND: It has been thought that the occurrence of multiple sclerosis (MS) could be associated with daily ultraviolet exposure. In this study we investigated the geospatial association between average daily ultraviolet B (UVB) irradiance and MS prevalence in Newfoundland and Labrador (NL), Canada. METHODS: A complete list of patients diagnosed with MS in the province of NL was constructed. Places of habitation from birth to diagnosis were ascertained by mailout survey. RESULTS: A 74% rate of return on the survey results was obtained. A plot of the average daily erythemal UV over the available five years (1998-2002) shows that the distribution of MS follow a north-south gradient. Average daily UVB measurements are lower in the higher latitudes. A statistically significant negative correlation of MS incidence with erythemal UVB was found that is stronger than the correlation using latitude. This correlation appears to be strongest in the first year of life and declines when subsequent years are examined up to age ten. No significant correlation was found for the subjects' locale of habitation at the time of their first MS attack. CONCLUSIONS: This study suggests that UVB radiation may contribute to the pathogenesis of MS.

The relation between menarche and the age of first symptoms in a multiple sclerosis cohort.

BACKGROUND: Previously, multiple sclerosis (MS) has been thought to be associated with changes in hormone levels. This study investigates the association between the age of menarche and the age of onset of the first symptoms of MS. METHODS: A complete list of patients diagnosed with MS in the province of Newfoundland and Labrador was constructed. The age of menarche for our entire relapsing remitting female MS (RRMS) population was requested by mailout survey. Age of symptom onset was ascertained by chart review. RESULTS: A 74% rate of return on the survey results was obtained (150 RRMS patients). A linear regression model demonstrated that the age of first symptoms increased by 1.16 years as the age of menarche increased by one year (R2 = 0.69, P = 0.04). Another analysis showed that the average age of first symptoms for women with reported menarche from 10 to 12 years was 28.96 years compared with 31.83 years for a reported menarche from 13 to 15 years, a significant difference (P = 0.047, t-test). CONCLUSIONS: This study suggests that menarche may be related to the pathogenesis of MS.

Co-occurrence of autoimmune thyroid disease in a multiple sclerosis cohort.

BACKGROUND: Multiple sclerosis (MS), Hashimoto's disease and Graves' disease are autoimmune diseases that may share similar pathogenic mechanisms. The co-occurrence rates and demographic characteristics of Graves' disease and Hashimoto's disease (HT) in our MS population are compared with the general population. METHODS: The prevalence of thyroid disease in our MS patients was determined by chart review and survey. Previous diagnosis of thyroid disease, age at diagnosis, treatment used, and about the use of disease modifying medications used to treat their MS were asked. Chart reviews were used to estimate the population prevalence of Graves' disease and Hashimoto's disease and to estimate the demographics of patients with thyroid disease. RESULTS: A significant co-occurrence of Graves' disease with MS (p = 0.002), and a non-significant co-occurrence of Hashimoto's disease were noted (p = 0.097). No difference in the age of onset or gender of thyroid disease in MS patients compared to the general population was found. CONCLUSION: There is a significant co-occurrence in patients with MS and Graves' disease, and a trend to co-occurrence in patients with MS and Hashimoto's disease. There are no differences in the demographics of patients with thyroid disease in our MS patients compared to the general population.

The mechanism of action of methylprednisolone in the treatment of multiple sclerosis.

Methylprednisolone plays an important role in the current treatment of multiple sclerosis (MS), particularly in the acute phase of relapse. It acts in various ways to decrease the inflammatory cycle including: dampening the inflammatory cytokine cascade, inhibiting the activation of T cells, decreasing the extravasation of immune cells into the central nervous system, facilitating the apoptosis of activated immune cells, and indirectly decreasing the cytotoxic effects of nitric oxide and tumor necrosis factor alpha. This paper reviews the most recent observations on these mechanisms both to understand the disease mechanism and its treatment. As more becomes known about these mechanisms, it may become possible to design treatment regimes that are more specific towards both the individual and the disease state.

Incidence and prevalence of multiple sclerosis in Newfoundland and Labrador.

BACKGROUND: The incidence and prevalence of multiple sclerosis (MS) in Newfoundland and Labrador (NL) had been reported in 1984 and was considered to be relatively low at that time. This study revisits the incidence and prevalence of MS in NL for the year 2001. METHODS: Case searches through patient files of neurologists in NL were conducted. A complete list of patients billed for MS in NL between 1996 and 2003 was obtained and all cases were confirmed via chart review. RESULTS: There were 493 living MS patients yielding a prevalence of 94.4/100,000 which is significantly higher than previously reported. Of the living patients, 330 had relapsing remitting (RRMS), 94 had secondary progressive, 66 had primary progressive (PPMS) and three had unspecified MS. The total female to male ratio was 2.7:1. There was no difference between the female to male ratios for RRMS vs PPMS. Patients with PPMS had a later onset compared to RRMS (p<0.00001). Yearly incidences were relatively constant from 1994 to 2001 (5.6/100,000). Significant delays between first symptoms and final diagnosis were common and the delay time has not changed over the past 15 years. A prevalence of 88.9/100,000 was estimated from survival and incidence trends and was not significantly different than the measured prevalence (p=0.38). CONCLUSIONS: The increase in incidence and prevalence are accounted for through both better access to diagnostic facilities and more practicing neurologists. The revised prevalence and incidence are more in keeping with recently reported values throughout Canada.

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.