MULTIPLE SCLEROSIS

GEOGRAPHIC DISTRIBUTION



THIS DEALS WITH THE GEOGRAPHIC DISTRIBUTION OF MS

MULTIPLE SCLEROSIS SOCIEOECONOMIC FACTORS

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FREQUENCY CRITERIA

The world estimate is 1.11 to 2.5 million cases of MS, with Western Europe having 350,000, and U.S.A. having 250,000 cases.

The high frequency zones for MS at 50-120/100,000 population are Europe, Canada, USSR, Israel, Northern U.S.A., New Zealand and South-East Australia.

Lowest frequency zones for MS at 5/100,000 population are Asia, Africa and South America

No one knows exactly how many people have MS.  Estimate in the U.S.A. range from less than 200,000 to 500,000.

Canada and USA, prevalence are lowest in the southern USA, become higher in the northern states and are highest in Canada (Kurtzke, 1980).

In western Europe the gradient is not as well expressed but prevalence are higher in the Nordic countries and Britain than in the more southerly Mediterranean countries (Rosati, 1994).

The north/south gradient is well expressed in Australia and New Zealand with the highest prevalence in the temperate, southern portions of these countries (Sadovnick and Ebers, 1993).
 

 Worldwide, MS occurs with much greater frequency in higher latitudes (between 40° and 60 degrees north and south latitude.

In the U.S., MS occurs more frequently in states that are above the 37th parallel than in states below it. From east to west, the 37th parallel extends from Newport News, VA, to Santa Cruz, CA—running along the northern border of North Carolina to the northern border of Arizona and including most of California. The MS prevalence rate for the region below the 37th parallel is 57 to 78 cases per 100,000 people. The prevalence rate for those above the 37th parallel is 110 to 140 cases per 100,000 people. Nationwide, there are an estimated 250,000 to 350,000 people with MS.

Certain outbreaks or clusters of MS have been identified, but their significance is not known.

MS also shows large differences in prevalence within some individual countries in the high risk area. For example in Norway MS is up to five times more common in the inland farming areas than in the relatively nearby coastal fishing areas (Alter, 1977).

Scandinavia and Scotland have a higher incidence than other European countries

In Canada, MS is at least twice as prevalent in the Prairie provinces (100-225) as it is on the island of Newfoundland (50) (Sadovnick and Ebers, 1993).  It is also much higher in Pincher Creek, Alberta for unknown reasons.  Saskatchewan has the highest rate on the prairies.

Japan does not conform to the north south distribution of MS.  Some suggest that Japan MS are usually DR-2 positive (HDL DR 2 Haplotype).  B35-DR-2, B15-DR 2, B51-DR 2 are the most common Haplotypes.  The association of MS with DR 2 probably indicates an immune response mechanism.

Crucial data for constraining the nature of the environmental factor come from prevalence for both those of Japanese and Caucasian descent in Hawaii. Those of Japanese descent have a prevalence of 6.5 (i.e. 6.5 Japanese with MS per 100,000 Japanese in Hawaii) which is over three times that of Japan (2.1) (Kuroiwa et al., 1983; Alter et al., 1971). Conversely the Caucasians who were born and raised in Hawaii have a prevalence of 10.5 which is only one third that of the Caucasians of California (29.9) (Poser, 1994).

France should be a high risk area but isn’t ?

The rarity of MS among Samis, Turkmen, Uzbeks, Kazakhs, Kyrgyzis, native Siberians, North and South Amerindians, Chinese, Japanese, African blacks and New Zealand Maoris, as well as the high risk among Sardinians, Parsis and Palestinians, clearly indicate that the different susceptibilities of distinct racial and ethnic groups are an important determinant of the uneven geographic distribution of the disease.

United Kingdom  85,000 people in United Kingdom have multiple sclerosis.  Orkney and Shetland Islands have the highest rates in the world.

                 S.E. Scotland is 203-219/100,000 population
                N.E. Scotland is         144/100,000 population

Canada  50,000 people in Canada have multiple sclerosis.  Recent studies suggest Canada is second only to Finland in having the steepest rates of Ms.
 

 Canada MS is 100/100,000 population
 Western Canada is 93-111/100,000 population
 Prairie Provinces Ms rate 340/100.000 population
 Newfoundland Ms rate   50/100,000 population

 Alberta has one of the highest rates of Ms 313/100,000 population 

           Black Diamond and Turner Valley has 354/100,000 population
            This makes this area one of the highest in the world

 Barrhead is 196/100,000 population
   50% British origin
   50% Northern European origin
   The rate is 50% men 50% women
  Crowsnest Pass is 217/100,000 population
  Westlock is 200/100,000 population
   40% are of British origin
   60% are of Northern European origin
   48% of cases are R/R MS
  Cardston is 88/100,000 population

Some suspect the high rate of Ms in Turner Valley/Black Diamond is the result of pollution specifically sour gas wells.  The possible link is being researched.  2001

 Saskatchewan

  Saskatoon is 134/100,000 population

   Residence are 64/100,000
   Saskatchewan born 77/100,000
   Immigrants are 48/100,000

 British Columbia is 93/100,000 population

United States  250,000-500,000 people in the United States are estimated to have multiple sclerosis,  8000 new cases are reported each year

 South of 37 parallel Ms rate    57-78/100,000 population
 North of 37 parallel Ms rate 110-140/100,000 population

California Ms rate is 29.9/100,000 population
Colorado rate is 84/100,000 population
New Mexico is 3-4/100,000 population
 Los Alamos is 76/100,000 population

The States with the highest rate of Ms are:

1. Vermont
2. Washington
3. Minnesota   61/100,000
4. Wyoming
5. Montana & Idaho

European Countries

 Germany is 63/100,000 population
 Greece
      Northern Greece is 29/100,000 population
 Italy is 65-78/100,000 population
      Central Italy is 34/100,000 population
 Norway
      Western Norway is 60/100,000 population
 Poland (cluster) is 118/100,000 population
 Romania is 30/100,000 population
 Scotland
      N.E. Scotland is        144/100,000 population
      S.E. Scotland is 203-219/100,000 population
 Spain
      Northern Spain is 58/100,000 population
 Switzerland is 110/100,000 population

Australia is 0/100,000 population among aboriginal people

MS OUTBREAK ?

The following study has been proven to be inaccurate as the actual date of contracting the disease predates the arrival of the British Soldiers.

One of the most interesting and widely quoted epidemiological studies of MS is that of the greatly increased prevalence of MS in the Faroe Islands (North Atlantic, west of Norway) following the occupation by 1500-2000 British troops between 1941 and 1944 (Kurtzke, 1977, 1980, 1995). Kurtzke has classified this increase as an epidemic although other authors have challenged this view (Benedikz et al., 1994, Poser et al. 1988). Regardless, there can be no doubt that MS prevalence substantially increased in the Faroes following the British occupation. Furthermore, the relationship between MS in the Faroe islanders and the presence of British soldiers is strongly supported by the fact the cases of MS all occurred in islanders who lived close to British bases (Kurtzke, 1980, fig. 15). This is an extremely important constraint because it demonstrates that the environmental factor is not solely indigenous and can transported from one area to another. .  Similar outbreaks were reported in Shetland & Orkney Islands, in Iceland and in Sardinia.  Specific point agents were never identified.

MIGRATION THEORY

It is suggested that adult immigrants retain the risk factor of their country of origin whereas their children tend towards the risk factor of the country they have immigrated to. (Alter et al., 1966; Dean and Kurtzke, 1971).

An individual who is born in an area with a higher risk of developing MS and moves to an area of lower risk, acquires the risk of the new home if the move occurs before the individual is 15 years old.

Immigrants to London, U.K. from areas of low risk (e.g. West Indies) have a low prevalence but their British-born children have the same high prevalence as British Caucasians (Elian et al., 1990).

Indian, Pakistani and Bangladeshi who enter England younger than 15 yrs old had a higher rate of Ms than those who entered after age 15 years old.  The same study included Caribbean immigrants who have a higher Ms prevalence than Asian immigrants did not show the same difference.
 

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