Increasing Incidence of Multiple Sclerosis in the Province of Sassari, Northern Sardinia

Epidemiology of aquaporin-4-IgG-positive NMOSD in Sardinia

PURPOSE

The Italian Island of Sardinia (population, 1,578,146) is recognized for the high risk of multiple sclerosis (MS) but the epidemiological burden of other less common demyelinating diseases of the central nervous system (CNS), such as aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD), is unknown. In this study, we determined the incidence and prevalence of AQP4-IgG+NMOSD in Sardinia over a ten-year study period (2013-2022).

METHODS

Patients with a diagnosis of AQP4-IgG+NMOSD (per 2015 IPND diagnostic criteria) were retrospectively identified using two sources: (1) Archives of the reference and only laboratory for AQP4-IgG testing in Sardinia; and (2) medical records of the four MS units in the island. Incidence (January 2013-December 2022) and prevalence (December 31, 2022) were calculated.

RESULTS

A total of 45 cases were included: incident, 31; prevalent, 41. The median age (range) at disease presentation was 51 (6-78) years; female/male ratio was 9:1. The crude (95 % CI) incidence and prevalence were 1.9 (1.3-2.7) per million and 2.6 (1.9-3.5) per 100,000, respectively. Prevalence increased from 2013 (1.1 per 100,000) to 2022 (2.6 per 100,000); p = 0.002. After age-standardization to the world, incidence and prevalence (95 % CI) decreased to 1.3 (0.7-2) per million and 1.8 (1.3-2.3) per 100,000, respectively. Coexisting immune-mediated disorders, mostly autoimmune thyroiditis, were reported in 50 % of patients.

CONCLUSIONS

The epidemiology of AQP4-IgG+NMOSD in Sardinia is overall in line with other Caucasian populations. The high MS risk in the island seems disease-specific and not associated with an increased risk of other CNS demyelinating disorders, confirming different pathophysiology.

Effect of Whole-Body Cryotherapy on Oxidant-Antioxidant Imbalance in Women with Multiple Sclerosis

The aim of the study was to investigate whether 20 whole-body cryotherapy treatments have an effect on oxidative-antioxidant imbalances in women with multiple sclerosis. Fifty women aged 30-55 were examined: study group-15 women with multiple sclerosis, subjected to whole-body cryotherapy; first control group-20 women with multiple sclerosis who did not receive cryotherapy intervention; second control group-15 healthy women who participated in cryotherapy treatments. Blood from the examined women was collected twice (before and after the series of 20 cryotherapy sessions). An insignificant increase in the total antioxidant capacity (study group: p = 0.706; second control group: p = 0.602) was observed after the whole-body cryotherapy intervention. After the series of cryotherapy sessions, the total oxidative status/total oxidative capacity value was insignificantly decreased among the multiple sclerosis patients (decrease by 14.03%, p = 0.495). In women with multiple sclerosis, no significant cryotherapy impact was demonstrated on changes in the oxidant-antioxidant imbalance or concentrations of nitric oxide, uric acid, or matrix metalloproteinase-9.

Multiple sclerosis epidemiological trends in Italy highlight the environmental risk factors

Italy is definitely a high-risk country for multiple sclerosis (MS). Over the last 50 years, several epidemiological studies, including longitudinal surveys, have disclosed that MS incidence and prevalence in Italy mainland and Islands (Sardinia and Sicily) have progressively increased, picturing a semi-parabolic curve. Based on the comprehensive scrutiny of 58 papers, we conclude that the latitude risk gradient does not fit to the Italian map of MS. The genetic heterogeneity of the Italian ethnicities, that likely forms the basis of MS predisposition, does not account for the dramatic increase of MS incidence and prevalence observed in Italy over the last half century that, rather, seems better explained by the effect of environmental factors.

Age and sex adjusted prevalence and annual incidence of multiple sclerosis in East-Azerbaijan, Iran

BACKGROUND

Incidence and prevalence of multiple sclerosis (MS) is postulated to be rising in recent decades. Therefore, updating and completing the information of patients is essential, especially in high population areas. East-Azerbaijan is the largest and most populous province in the northwest of Iran. This study aimed to determine the prevalence and annual incidence of MS from 2008 to 2017 in East-Azerbaijan.

METHODS

We evaluated the data of all patients who had registered at the MS center in the university hospital. The data include nearly all MS patients in the East-Azerbaijan region, because it is the only referral site in the area. All of the reported rates were calculated in 100,000 of the total population.

RESULTS

By the end of 2017, the number of MS patients was 2995 (residing in the, with 769 (25.67%) men and 2226 (74.32%) women. The prevalence rate was 75.72/100,000 (95 % CI: 73.06-78.48), 38.2 in men (95% CI: 35.5-41.0), and 114.61 for women (95% CI: 109.9-119.4), with a female to male (F/M) ratio of 3:1. The mean annual incidence rate was 7.63/100,000 (95% CI: 5.6-9.3), and this rate was higher in women than men. During the nine years, the incidence rate increased. The patients' mean age was 32.33 ± 8.92, with a peak prevalence in 25-29 years for both genders. In this study, 13.9% of patients had a positive MS family history.

CONCLUSIONS

This study showed a high prevalence of MS in the region. There is a significant increase in the incidence of MS during the nine years in East-Azerbaijan. The increment of incidence was more prominent in women. Also, considering the increasing incidence rate, it is concluded that the risk of MS is increasing in this region.

Incidence of multiple sclerosis in Iran: a nationwide, population-based study

OBJECTIVES

The incidence of multiple sclerosis (MS) is not well known in Iran. This study was conducted to estimate the trends in annual MS incidence in Iran from March 21, 2010, to March 20, 2016.

STUDY DESIGN

Longitudinal study.

METHODS

In this longitudinal study, data for all MS patients fulfilling McDonald criteria were obtained from a national registry, coordinated by the Ministry of Health (MOH). In Iran, all MS patients are eligible to receive public care and treatment services based on their records in this registry, and thus nearly all MS patients are registered in this database. The annual incidence rates were calculated based on year of diagnosis and were standardized using the World Health Organization (2000-2025) population as a standard.

RESULTS

In this registry, 36,287 (8202 [22.6%] males and 28,085 [77.4%] females) confirmed MS cases were registered by the MOH between 2010 and 2016. The female-to-male ratio was 3.11. The mean age of patients was 31.6 ± 0.9 years at the time of diagnosis. It was 31.3 ± 0.8 and 32.3 ± 0.9 for females and males, respectively. Overall incidence rate was 6.7/100,000 population (95% confidence interval [CI]: 6.2-7.2); 10.5 and 3.0 in females and males, respectively. The age-adjusted incidence rates increased significantly from 4.4 (95% CI: 4.3-4.6) in 2010 to 5.8 (95% CI: 5.7-6.0) in 2016, with its peak at 6.5 (95% CI: 6.3-6.6) in 2014.

CONCLUSIONS

This study revealed that Iran is a high-risk area for MS disease and that MS incidence and female-to-male ratio are more or less comparable with the dominant patterns in developed countries. Also, this study showed that the incidence trend of MS in Iran is similar to regional and global observed patterns.

Prevalence of multiple sclerosis in Sardinia: A systematic cross-sectional multi-source survey

Background:

Partial surveys in sub-regions of Sardinia have suggested a high prevalence of multiple sclerosis (MS) on the island, relative to other Mediterranean populations. We assessed the island-wide prevalence of MS and its detailed distribution in Sardinia.

Methods:

The study population consisted of 5677 MS patients, 1735 men and 3942 women, living in Sardinia. Neurologists retrospectively examined electronic and paper-based records of patients with a diagnosis of MS. The data were then linked to the administrative health information systems. Crude, age-, and sex-specific prevalence estimates of disease were calculated.

Results:

The overall age-adjusted MS prevalence was 330 per 100,000 (95% confidence interval (CI) 321–338) in individuals older than 15 years, 447 in women (95% CI 433–461), and 205 in men (95% CI 195–214). The prevalence was highest in the Ogliastra and Nuoro districts, respectively, 425 (95% CI 372–478) and 419 (95% CI 387–451), and lowest in the Olbia-Tempio district, 217 (95% CI 195–239). Most cases had relapsing–remitting MS (79.3%), 16.3% had secondary-progressive MS, and 4.4% had primary-progressive MS.

Conclusion:

These prevalence are among the highest reported so far worldwide. They provide estimates for comparative analyses in other populations and are essential for public health interventions.

Pediatric-onset multiple sclerosis and other acquired demyelinating syndromes of the central nervous system in Denmark during 1977-2015: A nationwide population-based incidence study

BACKGROUND

The incidence of acquired demyelinating syndromes (ADS) including multiple sclerosis (MS) has never been investigated in a Danish pediatric population.

OBJECTIVES

We estimated the nationwide age- and sex-specific incidence of pediatric ADS including MS.

METHODS

Data were sourced from the Danish Multiple Sclerosis Registry, providing cases of pediatric MS for 1977-2015, and the National Patient Register, providing cases of ADS during 2008-2015. All medical records were reviewed to validate the register-based diagnoses.

RESULTS

We identified 364 cases of pediatric MS occurring during 1977-2015 (incidence rate = 0.79 per 100,000 person-years). MS was exceptionally rare before puberty, but the incidence rose considerably from 9 years in girls and 11 years in boys. The female-to-male ratio was 2.5; the median age at onset was 16 years (range = 7-17 years). The MS incidence rate was relatively stable through the study period. During 2008-2015, we identified 219 ADS cases. The incidence was 2.29 per 100,000 person-years with considerable differences in the age peaks for the separate ADS.

CONCLUSION

The incidence rates of MS and other ADS in Denmark were higher than those reported for some other European countries. Referral bias and classification differences may account for this disparity, in particular the age-intervals and the definition of onset.

Age at Menarche and Risk of Multiple Sclerosis: A Prospective Cohort Study Based on the Danish National Birth Cohort

Few studies have addressed the possible association between age at menarche and multiple sclerosis (MS), and results are conflicting. We studied this issue in a large prospective cohort study. The study cohort comprised 77,330 women included in the Danish National Birth Cohort (1996-2002). Information on menarcheal age was ascertained at the first interview, which took place in the 16th week of pregnancy. Women were followed for MS from the first interview to December 31, 2011. Associations between age at menarche and risk of MS were evaluated with hazard ratios and 95% confidence intervals using Cox proportional hazards regression models. Overall, 226 women developed MS during an average follow-up period of 11.7 years. Age at menarche among women with MS was generally lower than that among women without MS (Wilcoxon rank-sum test; P = 0.002). We observed an inverse association between age at menarche and MS risk. For each 1-year increase in age at menarche, risk of MS was reduced by 13% (hazard ratio = 0.87, 95% confidence interval: 0.79, 0.96). Early age at menarche appears to be associated with an increased risk of MS. The mechanisms behind this association remain to be established.

Estimated prevalence of multiple sclerosis in Italy in 2015

Italy is a high risk area for multiple sclerosis (MS) as confirmed by the numerous prevalence and incidence studies conducted in several regions/districts of the country. Nevertheless, there are no recent published epidemiological data, nor studies about the total prevalence of MS in Italy. Our aim was to update as of 2015 the prevalence rates of MS in different geographical areas using already published epidemiological studies, and to estimate the overall prevalence of the disease in Italy. We made a search in MEDLINE database of all published studies on epidemiology of MS in Italy. Then, we applied, to the already published prevalence data, the last published incidence and mortality rates to recalculate, as of 2015, the prevalence of MS. So, we calculated the mean prevalence rate from our extrapolations, and we applied it to the population in 2015 to estimate the number of MS patients in Italy. Our prevalence extrapolations ranged from 122 to 232 cases/100,000 in the mainland and Sicily, with an average of 176/100,000, and from 280 to 317 cases/100,000 in Sardinia with an average of 299/100,000. Applying these media to the Italian population in 2015, we obtained an estimate of more than 109,000 MS patients in Italy. Our estimates were higher than the latest published rates but consistent with the annual increase of prevalence due to incidence that exceeds mortality, with the increase of survival and, maybe, with the probable increase of incidence.

Multiple sclerosis-associated retrovirus in early multiple sclerosis: a six-year follow-up of a Sardinian cohort

The human endogenous retroviruses (HERV)-W family contains an extracellular particle detected in multiple sclerosis (MS) patients and designated as MS-associated retrovirus (MSRV). Through nested RT-PCR assays specific for pol MSRV gene, we preliminary reported that its presence in the cerebrospinal fluid (CSF) of early MS patients could be indicative of a poor prognosis upon a three-year follow-up. In the present clinical study, we enlarged our blind observation up to six years. At study entry, 10 MS patients were MSRV- and eight were MSRV+ in the CSF, both groups having a similar mean age and Expanded Disability Status Scale (EDSS) score. After six year follow-up, the mean EDSS significantly differed between the MSRV- and MSRV+ cohorts (4.3 versus 2.2; P = 0.004), as did the annual relapse rate (0.5 in the MSRV- versus 0.3 in the MSRV+; P = 0.01). Finally, two MSRV- patients entered the progressive phase, whilst none of the MSRV+ group entered this phase, and 9/10 MSRV- versus 2/8 MSRV+ patients were treated with immunomodulatory or immunosuppressive drugs (P = 0.009). In conclusion, we found that the presence of MSRV virions in the CSF at the onset of MS is associated, not only with disability accumulation, but also with a higher rate of clinical re-exacerbations. With the known potential pathogenic effects of MSRV given in the literature, further investigations on MSRV are warranted.

Epidemiology of multiple sclerosis in the pediatric population of Sardinia, Italy

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Several authors report MS affecting not only young adults but also children and adolescents. Sardinia is one of the regions at the highest risk for MS worldwide in the adult population; to date, no definite data exist on the pediatric population. The aim of this study was to estimate the incidence and prevalence of pediatric MS (pMS) in northern Sardinia. Patients with diagnosis of optic neuritis, myelitis, acute disseminated encephalomyelitis (ADEM), demyelinating disorders, MS, or clinically isolated syndrome (CIS) according to McDonald criteria were enrolled, when disease onset occurred within the range of 0-18 years. From January 1, 2001 to December 31, 2012, 21 cases of pMS and 5 cases of CIS were found in northern Sardinia. The annual mean pMS incidence was 2.85 cases per 100,000 pediatric population, and the annual mean CIS incidence was 0.68 cases per 100,000 pediatric population. The pMS and CIS prevalence computed on 31 December 2012 was 26.92 and 6.41 per 100,000 pediatric population, respectively.

CONCLUSION

Our pMS data among Sardinians corroborate the epidemiological scenario described in the adult population being the incidence estimates significantly higher than those reported elsewhere.

WHAT IS KNOWN

Sardinia is one of the regions at the highest risk for MS worldwide in the adult population. To date, no definite data exist on the pediatric population.

WHAT IS NEW

The pediatric MS incidence in Sardinia is estimated to be significantly higher than those reported elsewhere. The pediatric MS prevalence in Sardinia is among the highest values worldwide.

Sex-Based Differences in Multiple Sclerosis (MS): Part II: Rising Incidence of Multiple Sclerosis in Women and the Vulnerability of Men to Progression of this Disease

It is well known that a number of autoimmune diseases including multiple sclerosis (MS) predominantly affect women and there has been much attention directed toward understanding why this is the case. Past research has revealed a number of sex differences in autoimmune responses that can account for the female bias in MS. However, much less is known about why the incidence of MS has increased exclusively in women over the past half century. The recency of this increase suggests that changing environmental or lifestyle factors are interacting with biological sex to increase MS risk predominantly in females. Indeed, a number of recent studies have identified sex-specific differences in the effect of environmental factors on MS incidence. The first part of this chapter will overview this evidence and will discuss the possible scenarios of how the environment may be interacting with autoimmune mechanisms to contribute to the preferential rise in MS incidence in women. Despite the strong female bias in MS incidence, culminating evidence from natural history studies, and imaging and pathology studies suggests that males who develop MS may exhibit a more rapid decline in disability and cognitive functioning than women. Very little is known about the biological basis of this more rapid deterioration, but some insights have been provided by studies in rodent models of demyelination/remyelination. The second part of this chapter will overview the evidence that males with relapsing-onset MS undergo a more rapid progression of disease than females and will discuss potential biological mechanisms that account for this sex difference.

The co-occurrence of multiple sclerosis and type 1 diabetes: shared aetiologic features and clinical implication for MS aetiology

We reviewed the evidence for the co-occurrence of type 1 diabetes mellitus (T1D) and multiple sclerosis (MS), and assessed the clinical significance of this association and the shared aetiological features of the two diseases. T1D and MS contribute considerably to the burden of autoimmune diseases in young adults. The co-occurrence of MS and T1D has been reported by a number of studies, suggesting that the two conditions share one or more aetiological components. Both conditions have been associated with distinct human leukocyte antigen (HLA) haplotypes but share a number of similarities in clinical, epidemiological and immunological features, leading to suggestions of possible common mechanisms of development. While underlying genetic factors may be important for the co-occurrence of both conditions, some evidence suggests that environmental factors such as vitamin D deficiency may also modulate an individual's risk for the development of both conditions. Evidence on whether the co-occurrence of the two autoimmune conditions will affect the disease course and severity of MS is merely absent. Further studies need to be conducted to ascertain whether the neuropathology associated with T1D might influence the disease course and contribute to the severity of MS.

In vitro assessment of the direct effect of laquinimod on basic functions of human neural stem cells and oligodendrocyte progenitor cells

Laquinimod is an orally active immunomodulatory small molecule that has shown clear clinical benefit in trials for relapsing-remitting multiple sclerosis and in experimental rodent models that emulate multiple sclerosis (MS). Studies in healthy mice, and in mice with experimental autoimmune encephalomyelitis, have demonstrated that laquinimod is capable of entering the central nervous system. It is therefore important to determine if laquinimod is capable of a direct influence on basic functions of neural stem cells (NSC) or oligodendrocyte progenitor cells (OPC)--cells critical for myelin repair in MS. In order to address this question, a series of experiments was conducted to determine the effect of exogenous laquinimod on viability, proliferation, migration and differentiation of human NSC and OPC in vitro. These data show, for the first time in cells of human origin, that direct, short-term interaction between laquinimod and NSC or OPC, in an isolated in vitro setting, is not detrimental to the basic cellular function of these cells.

Multiple Sclerosis in the Mount Etna region: possible role of volcanogenic trace elements

BACKGROUND

Trace elements have been hypothesised to be involved in the pathogenesis of Multiple Sclerosis and volcanic degassing is the major natural sources of trace elements. Both incidence of Multiple Sclerosis in Catania and volcanic activity of Mount Etna have been significantly increased during the last 30 years. Due to prevailing trade winds direction, volcanic gases from Etna summit craters are mostly blown towards the eastern and southern sectors of the volcano.

OBJECTIVE

To evaluate the possible association between Multiple Sclerosis and exposure to volcanogenic trace elements.

METHODS

We evaluated prevalence and incidence of Multiple Sclerosis in four communities (47,234 inhabitants) located in the eastern flank and in two communities (52,210 inhabitants) located in the western flank of Mount Etna, respectively the most and least exposed area to crater gas emissions.

RESULTS

A higher prevalence was found in the population of the eastern flank compared to the population of the western one (137.6/100,000 versus 94.3/100,000; p-value 0.04). We found a borderline significantly higher incidence risk during the incidence study period (1980-2009) in the population of the eastern flank 4.6/100,000 (95% CI 3.1-5.9), compared with the western population 3.2/100,000 (95% CI 2.4-4.2) with a RR of 1.41 (95% CI 0.97-2.05; p-value 0.06). Incidence risks have increased over the time in both populations reaching a peak of 6.4/100,000 in the eastern flank and of 4.4/100.000 in the western flank during 2000-2009.

CONCLUSION

We found a higher prevalence and incidence of Multiple Sclerosis among populations living in the eastern flank of Mount Etna. According to our data a possible role of TE cannot be ruled out as possible co-factor in the MS pathogenesis. However larger epidemiological study are needed to confirm this hypothesis.

Epidemiology and clinical record of multiple sclerosis in selected countries: a systematic review

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system mainly affecting young adults. The aim of this paper is to review the literature concentrating the main national MS registries in selected countries of the world. We performed a systematic review to determine the MS epidemiology reported on prevalence, incidence, environmental factors, treatment, social consequences of MS and neurological disability or progression among MS-affected people. We got the information on the high-MS prevalence in Sardinia, Sweden or Sicily and on the effects of MS treatment in United States of America, Italy or Germany. We emphasized environmental factors taking into account as MS risk factors. We concluded that there were many descriptions of MS status in particular countries, but they were often insufficiently detailed and not uniform enough to compare it. The paper indicated an importance of the MS epidemiology in the light of the healthcare or quality of life of the MS patients, but further research is needed to optimize this issue.

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.

Increasing prevalence and incidence rates of multiple sclerosis in Kuwait

Background:

Kuwait was considered as low to intermediate risk area for MS.

Objectives:

To determine the prevalence and incidence rates of MS among Kuwaiti nationals based on 2011 population census.

Methods:

This cross-sectional study was conducted between October 2010 and April 2013 using the newly developed national MS registry in Kuwait. Patients with a diagnosis of MS according to 2010 revised McDonald criteria were identified. The crude, age- and sex-specific prevalence and incidence rates among Kuwaiti patients were calculated.

Results:

1176 MS patients were identified of which 927 (78.8%) were Kuwaitis and 249 (21.2%) were expatriates. Among Kuwaiti patients, female to male ratio was 1.8:1 with a mean age of 35.40 ± 10.99 years. The prevalence rate of MS was 85.05 per 100,000 persons (95% CI: 82.80 – 87.04). There was a peak in prevalence among patients aged 30–39 years. The incidence of MS was 6.88 per 100,000 persons (95% CI 5.52–8.55). Between 2003 and 2011, the incidence increased 3.22 and 2.54 times in women and men respectively.

Conclusion:

Kuwait is considered a high-risk area for MS. The significant increase in prevalence and incidence rates may represent a true increase despite the improvement in case ascertainment and case definition.

Concentration of 25(OH)D₃ and calcium and phosphorus metabolism in patients suffering from relapsing-remitting multiple sclerosis. A pilot study

BACKGROUND AND PURPOSE

The aim of this study was to evaluate the concentration of 25(OH)D₃ and the indices of calcium and phosphorus metabolism at different times of relapsing-remitting multiple sclerosis (MS). The relationships between the concentrations of 25(OH)D₃ and the indices of calcium-phosphate metabolism were determined, depending on the duration of disease and vitamin and unsaturated fatty acids supplementation.

MATERIAL AND METHODS

Thirty patients (15 at the early stage and 15 at the advanced stage of MS) were enrolled. Each patient underwent neurological examination; neurological motor disability was defined according to the Expanded Disability Status Scale (EDSS). The results were compared to the values obtained in the control group (15 individuals) selected according to the age of subjects, their residence, ethnicity and gender.

RESULTS

Significantly lower serum concentrations of 25(OH)D₃ in MS patients compared to the control group were found. MS patients at the advanced stage of the disease (duration of 5-6 years) had lower 25(OH)D₃ concentrations than patients at the early stage of MS. Among patients in an advanced stage of MS, significantly lower levels of 25(OH)D₃ were found in women compared to men with a similar level of physical disability.

CONCLUSIONS

Lower serum concentrations of 25(OH)D₃ in MS patients compared to the control group were found. The lowest concentrations of 25(OH)D₃ were found in female patients aged 20-40 and in patients with a longer disease duration without substantial impairment of calcium-phosphate metabolism.

There is much to be learnt about the costs of multiple sclerosis in Latin America

METHOD: A systematic review of the literature from 1990 to 2011 was conducted. Outcome measures included: mean cost of disease modifying therapies (DMTs), mean cost of treatment of relapses and mean cost of disease by stage stratification measured by the expanded disability status scale (EDSS). RESULTS: Seven studies from three countries (Brazil, Argentina and Colombia) were included. In 2004, in Argentina, the mean cost of DMT treatment was reported to be USD 35,000 per patient treated. In Brazil, the total MS expenditure of DMTs rose from USD 14,011,700 in 2006 to USD 122,575,000 in 2009. Patient costs ranged between USD 10,543 (EDSS 8-9.5) and USD 25,713 (EDSS 3-5.5). Indirect costs markedly increased for the EDSS 8-9.5 patients. CONCLUSION: Further research assessing the economic burden of MS in LA is warranted.

Incidence of multiple sclerosis among European Economic Area populations, 1985-2009: the framework for monitoring

Background

A debate surrounding multiple sclerosis epidemiology has centred on time-related incidence increases and the need of monitoring. The purpose of this study is to reassess multiple sclerosis incidence in the European Economic Area.

Methods

We conducted a systematic review of literature from 1965 onwards and integrated elements of original research, including requested or completed data by surveys authors and specific analyses.

Results

The review of 5323 documents yielded ten studies for age- and sex-specific analyses, and 21 studies for time-trend analysis of single data sets. After 1985, the incidence of multiple sclerosis ranged from 1.12 to 6.96 per 100,000 population, was higher in females, tripled with latitude, and doubled with study midpoint year. The north registered increasing trends from the 1960s and 1970s, with a historic drop in the Faroe Islands, and fairly stable data in the period 1980-2000; incidence rose in Italian and French populations in the period 1970-2000, in Evros (Greece) in the 1980s, and in the French West Indies in around 2000.

Conclusions

We conclude that the increase in multiple sclerosis incidence is only apparent, and that it is not specific to women. Monitoring of multiple sclerosis incidence might be appropriate for the European Economic Area.

The epidemiology of multiple sclerosis in Latin America and the Caribbean: a systematic review

The incidence and prevalence of multiple sclerosis (MS) varies geographically as shown through extensive epidemiological studies performed mainly in developed countries. Nonetheless, scant data is available in Latin America and the Caribbean (LAC). The objective of this review is to assess epidemiological data of MS in LAC. We conducted a systematic review of published articles and gray literature from January 1995 to May 2011. Twenty-two studies met the inclusion criteria after full-text review. Incidence data were found in only three studies and ranged from 0.3 to 1.9 annual cases per 100,000 person-years. Prevalence was reported in 10 studies and ranged from 0.83 to 21.5 cases per 100,000 inhabitants. The most prevalent subtype of MS was the relapsing–remitting form (48% to 91% of the series). No data about mortality were found. This study showed low frequency for MS in LAC compared with North American and European countries. The role of environmental and genetic factors should be well studied, providing new insights about its etiology.

Increased prevalence, incidence, and female predominance of multiple sclerosis in northern Japan

OBJECTIVE

To carry out the third epidemiologic surveillance of multiple sclerosis (MS) in Tokachi province, on the northernmost island of Japan, and to compare the results of the present survey on the prevalence, incidence, and characteristics of MS and neuromyelitis optica (NMO) with those of previous surveys performed in 2001 and 2006.

METHODS

A data processing sheet was sent to all MS-related institutions in Tokachi province, and all sheets were collected in March 2011. The criteria of Poser were used for diagnosing MS and the criteria proposed by Wingerchuk for diagnosing NMO. We then compared the results of the present survey with those of previous surveys performed in 2001 and 2006 in the same community.

RESULTS

Fifty-seven patients diagnosed with MS according to the criteria of Poser were identified. The prevalence was 16.2/100,000 in 2011, which was higher than in the previous studies. The female/male ratio of MS was 2.63, 2.75, and 3.38 in 2001, 2006, and 2011, respectively. Three patients fulfilled the criteria for diagnosis of NMO in 2011; the prevalence of NMO was 0.9/100,000.

CONCLUSIONS

The results of this study suggest that the prevalence and the female predominance of MS have been increasing, due to an increase in the incidence after 1990, and that the prevalence of NMO is relatively low in northern Japan.

Environmental factors in early childhood are associated with multiple sclerosis: a case-control study

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) with increasing incidence mainly in high-income countries. One explanation of this phenomenon may be a higher prevalence of allergic and autoimmune diseases in industrialized countries as a consequence of otherwise beneficial advances in sanitation (hygiene hypothesis). We investigated environmental factors in early childhood associated with MS.

METHODS

A case-control study was performed of 245 MS patients and 296 population-based controls in Berlin. The study participants completed a standardized questionnaire on environmental factors in childhood and youth, including aspects of personal and community hygiene. Multivariable logistic regression analysis was performed to investigate factors in childhood and youth associated with the occurrence of MS.

RESULTS

Mean age was 46 years (range, 20-80) in the MS group and 42 years (range 18-80) in the control group, of which 73.9% in the MS and 61.5% in the control group were female. The multivariable analysis showed that having at least two older siblings (OR 0.54; p = 0.05, for individuals with two older siblings compared to individuals without older siblings), attending a day-care center (OR 0.5; p = 0.004) and growing up in an urban center with more than 100, 000 inhabitants (OR 0.43; p = 0.009) were factors independently associated with a lower chance for MS.

CONCLUSIONS

The hygiene hypothesis may play a role in the occurrence of MS and could explain disease distribution and increasing incidence.

Epidemiology of multiple sclerosis in south-western Sardinia

BACKGROUND

Sardinia is a known high-risk area for multiple sclerosis (MS), but no data for south-western Sardinia (SWS) are available. SWS has a genetically homogeneous population, apart from St Peter Island, and represents a peculiar environment related to the industrial, mineralogical and military economy.

OBJECTIVE

To estimate prevalence and incidence and to evaluate temporal trends and geographical distribution of MS in SWS.

METHODS

MS prevalence was evaluated on 31 December 2007 and crude mean annual incidence rate was defined between 2003 and 2007. Temporal trend in MS incidence was assessed using the Armitage test. To identify MS clusters, Standard Morbidity Ratio (SMR) was calculated for each village and geographical distribution prevalence by means of a Bayesian hierarchical model.

RESULTS

Total crude prevalence rate was 210.4 (95% CI 186.3-234.5): 280.3 (95% CI 241.4-319.3) for females, 138 (95% CI 110.1-165.8) for males. The crude mean annual incidence rate was 9.7/100,000 (95% CI 3.4-13.2): 4.7/100,000 (95% CI 2.4-17.0) and 14.6/100,000 (95% CI 11.8-34.8) for males and females respectively. MS incidence has increased over the last 50 years. Cluster analysis showed an SMR of 0.2 (95% CI 0.05-0.68, p = 0.002) on the island of San Pietro, and 2.0 (95% CI 1.35-2.95, p = 0.001) in Domusnovas. Spatial distribution of MS was confirmed by Bayesian geographical analysis.

CONCLUSIONS

Our data confirm Sardinia as a high-risk area for MS and support the relevance of genetic factors in MS, as evidenced in St Peter Island. However, we found an unexpectedly high MS prevalence in one village, in particular in males, suggesting an environmental influence on MS occurrence.

Increasing frequency of multiple sclerosis in Catania, Sicily: a 30-year survey

Background and Objective: The objective of this study was to determine the prevalence and incidence of multiple sclerosis (MS) and its temporal profiles from 1975 to 2005 in the city of Catania.

Methods: The incidence of MS from 1975 to 31 December 1999 had been previously investigated by the same group. The frequency of MS in the community of Catania from 1 January 2000 to 31 December 2004 was studied in a population of 313,110 inhabitants (2001 census). All patients who satisfied Poser’s criteria were considered as prevalent and incident cases.

Results: Three hundred and ninety-eight patients with MS who had experienced the clinical onset of the disease before 31 December 2004 were found in a population of 313,110 inhabitants. The prevalence rate was 127.1/100,000 [95% confidence interval (CI) 115.1–140.4]. From 2000 to 2004, 108 patients with MS had clinical onset of the disease . The mean annual incidence was 7.0/100,000 (95% CI 5.7–13.7) and was higher in women (8.4/100,000; 95% CI 6.4–10.5) than in men (5.3/100,000; 95% CI 3.7–7.2). The mean length of time between the date of clinical onset and the date of the diagnosis was 1.4 ± 1.7 years. During the last 30 years the incidence of MS in this population increased from 1.3/100,000 during the first quinquennium (1975–9) to 7.0/100,000 during 2000–4.

Conclusions: Incidence rates have further increased in this population, suggesting that the risk of MS is still increasing.

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.

Factors associated with delay to medical recognition in two Canadian multiple sclerosis cohorts

Long referral and diagnostic delays can impact both the opportunity for early therapeutic intervention and estimates of MS incidence and prevalence. We investigated factors associated with diagnostic or referral delays within two geographically distinct MS Canadian cohorts and the association between referral delay and disability at first clinic visit. Adult-onset MS patients were selected from the population-based British Columbian MS (BCMS) (n=5705) and the clinic-based Hôpital Notre-Dame, Quebec (CHUM) (n=1489) databases. Referral delay (BCMS) and diagnostic delay (CHUM) were examined by sex, onset age, disease course (primary progressive (PPMS) vs. relapsing at onset), onset symptoms (BCMS only) and year of first clinic visit/diagnosis. Cohorts were analyzed separately by stratified analyses and multivariable linear modeling. The relationship between referral delay and initial disability was examined by multiple ordinal regression in the BCMS cohort. Younger at onset patients or those with PPMS exhibited significantly longer delays (p<0.001). Delays decreased over the 20+ year period, but reductions varied by clinical course, onset age and sex. Long referral delays were associated with greater disability at first clinic visit (p<0.001). If early intervention at mild disability levels is warranted in MS, then the extended delays to medical recognition for young adult-onset and PPMS patients must be addressed.

Age of onset in concordant twins and other relative pairs with multiple sclerosis

The ages of onset in multiple sclerosis cases span more than 7 decades. Data are presented for affected relative pairs from a Canadian population base of 30,000 multiple sclerosis index cases (1993–2008). The effects of genetic sharing, parent of origin, intergenerational versus collinear differences, and gender on the ages of onset were evaluated in the following concordant pairs: monozygotic twins (n = 29), dizygotic twins (n = 10), siblings (n = 614), first cousins (n = 405), half siblings (n = 29), parent/child (n = 285), and aunt/uncle/niece/nephew (avunculars) (n = 289). Fisher's z test assessed intraclass correlation (r) for ages of onset. Correlations for monozygotic twins, dizygotic twins, full siblings, and first cousins were 0.60, 0.54, 0.20, and 0.10, respectively. Dizygotic twins resembled monozygotic twins more than siblings. The age-of-onset correlation for maternal half siblings (r = 0.37) was higher than that for paternal half siblings (r = 0.26), consistent with other observations suggesting an intrauterine environmental effect on multiple sclerosis risk. Intergenerational comparisons are complicated by substantial increases of multiple sclerosis incidence over time. Genetic loading (familial vs. sporadic cases) did not generally influence the age of onset, but correlation of age of onset in multiple sclerosis relative pairs was proportional to genetic sharing. A maternal parent-of-origin effect on the age of onset in collinear generations was suggested.

Novel reliable real-time PCR for differential detection of MSRVenv and syncytin-1 in RNA and DNA from patients with multiple sclerosis

Two components of the HERV-W family of human endogenous retroviruses are activated during multiple sclerosis (MS) and proposed immunopathogenic co-factors: MSRV (MS-associated retrovirus), and ERVWE1 (whose env protein, syncytin-1, reaches the plasma membrane). MSRVenv and syncytin-1 are closely related, and difficult to distinguish each other. The sequences of extracellular MSRVenv and of syncytin-1 available in GenBank were compared with those found in MS patients and controls of the cohort under study. With respect to syncytin-1, MSRVenv sequences have a 12-nucleotide insertion in the trans-membrane moiety. Based on this insertion, discriminatory real-time PCR assays were developed, that can amplify selectively either MSRVenv or syncytin-1. The data of MS patients and controls indicated that MSRV and ERVWE1 are both expressed in the brain of MS patients, while only MSRV is present in the blood; MSRV was released in culture by PBMCs of MSRV-producer individuals. These cells expressed the complete MSRVenv gene in the absence of syncytin-1 expression, up to the final, fully glycosylated envelope protein product, since western blot staining with anti-HERV-Wenv antibody detected two bands of the same molecular weight (73 and 61kDa) of the fully glycosylated and partially glycosylated HERV-Wenv uncleaved proteins. Beyond MSRVenv DNA copy numbers were more abundant in MS patients than in healthy humans, while syncytin-1 were unchanged. These findings reinforce the link between MSRV and MS.

Risk assessment does not explain high prevalence of gestational diabetes mellitus in a large group of Sardinian women

BACKGROUND

A very high prevalence (22.3%) of gestational diabetes mellitus (GDM) was recently reported following our study on a large group of Sardinian women. In order to explain such a high prevalence we sought to characterise our obstetric population through the analysis of risk factors and their association with the development of GDM.

METHODS

The prevalence of risk factors and their association with the development of GDM were evaluated in 1103 pregnancies (247 GDM and 856 control women). The association of risk factors with GDM was calculated according to logistic regression. Sensitivity and specificity of risk assessment strategy were also calculated.

RESULTS

None of the risk factors evaluated showed an elevated frequency in our population. The high risk patients were 231 (20.9%). Factors with a stronger association with GDM development were obesity (OR 3.7, 95% CI 2.08-6.8), prior GDM (OR 3.1, 95% CI 1.69-5.69), and family history of Type 2 diabetes (OR 2.6, 95% CI 1.81-3.86). Only patients over 35 years of age were more represented in the GDM group (38.2% vs 22.6% in the non-GDM cases, P < 0.001). Type 2 diabetes in second-degree relatives was equally represented in GDM and non-GDM subjects, while prior poor obstetrical outcomes mostly characterized non-GDM women (17.5% vs 10.6%, P < 0.001). The "average risk" assessment better characterized non-GDM patients (76.8% vs 57.8%, P < 0.001). The logistic regression analysis confirmed that Type 2 diabetes in second-degree relatives, prior poor obstetrical outcomes and the "average risk" definition did not predict the development of GDM.

CONCLUSION

Such a high prevalence of GDM in our population does not seem to be related to the abnormal presence of some known risk factors, and appears in contrast with the prevalence of Type 2 diabetes in Sardinia. Further studies are needed to explain the cause such a high prevalence of GDM in Sardinia. The "average risk" definition is not adequate to predict GDM in our population.

Increasing prevalence and incidence of multiple sclerosis in northern Japan

BACKGROUND

We previously reported that prevalence of multiple sclerosis (MS) in Japan was 8.6/100,000 individuals in 2001. This was much higher than prevalence previously reported from Asian countries. A second epidemiologic survey was conducted to assess changes in MS prevalence and incidence over the last 30 years in Tokachi province of Hokkaido, the northernmost island of Japan.

METHODS

The authors studied the frequency of MS in the community of Tokachi Province, where the population has stabilized between 350,000 and 360,000 over the last 30 years. The survey was conducted at the same institutions using the same methods as the first survey in 2001.

RESULTS

On March 31, 2006, 47 subjects satisfied Poser's criteria for MS. The prevalence rate increased from 8.6 to 13.1/100,000 individuals between 2001 and 2006. The prevalence of conventional MS (C-MS) increased in five years although the prevalence of optic-spinal MS (OS-MS) did not increase. The mean annual incidence increased from 0.15 (1975-1989) to 0.68 (1990-2004).

CONCLUSIONS

The results show the highest MS prevalence in Asia; the increase in MS prevalence in Tokachi Province may be due to increased incidence after 1990.

Environmental risk factors in multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) likely results from an interaction between genetic and exogenous factors. While genetics shapes the overall population MS susceptibility, observed epidemiological patterns strongly suggest a role for the environment in disease initiation and modulation.

RESULTS

Findings from studies on seasonality in MS patients' birth, disease onset and exacerbations, as well as apparent temporal trends in incidence and gender ratio support an influential effect of viruses, metabolic and lifestyle factors on MS risk. Epstein-Barr virus, vitamin D status, and smoking are factors that may explain such epidemiological patterns.

CONCLUSIONS

Further epidemiological investigations are encouraged and opportunities to use data from existing cohort studies as well as the design of new studies should be pursued. In particular, the development of new large multicentre population-based case-control studies which incorporate the study of the role of environment and genetics, including epigenetic mechanisms, in determining MS risk is proposed.

Inhibition of multiple-sclerosis-associated retrovirus as biomarker of interferon therapy

The authors performed a longitudinal evaluation of multiple sclerosis (MS) patients, during 1 year of therapy with interferon-beta (IFN-beta), by clinical examination and detection of presence in the blood and viral load of MS-associated retrovirus (MSRV), by MSRVenv-specific, fully quantitative, real time reverse transcriptase-polymerase chain reaction (RT-PCR). MSRV load in the blood was directly related to MS duration and fell below detection limits within 3 months of IFN therapy; one patient had strong progression, accompanied by total MSRV rescue. These findings suggest that evaluation of plasmatic MSRV could be considered the first prognostic marker for the individual patient, to monitor disease progression and therapy outcome.

Prevalence and incidence of multiple sclerosis in Salerno (southern Italy) and its province

Many multiple sclerosis (MS) prevalence studies in Italian northern and central areas, since 1980, have put Italy in a high risk zone; none concerns southern Italy. The MS registry of Salerno Center was reviewed, including the city and 16 towns at different distances (9-149 km) better connected to our Center. Population screened: 259 681 persons (Salerno = 136 678; province = 123 003). Prevalence day was December 31, 2005. Data on 186 patients were collected of which 55 were males, 131 females; crude total prevalence = 71.6263 (62.03-82.303, ranging from 50.1128 (Oliveto Citra) to 431.499 (Controne). Salerno prevalence rate is 70.9697 (57.41-86.583); standardized = 72.02. Incidence rate ranges from 2.38585 (1.6-3.39) (1991-95) to 4.31997 (3.24-5.6) (2001-05). Our data can be underestimated because some patients could have skipped the local center. This emphasizes that the results, except for Sardinia, are comparable to Italian literature data. They confirm that this territory is a high risk area for MS. There is also an indirect indication against a latitude gradient for MS.