Descriptive Epidemiology of Multiple Sclerosis (MS)

1
Descriptive Epidemiology ofMultiple Sclerosis
(MS)
2
Course of Disease

• Acute - Very Rapid Course, Death in a few months
• Progressive - Gradually becoming worse, well
  defined remissions and exacerbations
• Benign - Exacerbations with very long
  remissions
• Subclinical - No Symptoms, identified at autopsy

3
Acute
Progressive
4
Epidemiology Incidence of MS in Denmark
5
Incidence of MS in Iceland
6
Incidence of MS in Faroe Islands
7
Incidence of MS in Faroe Islands by age
8
Years since 1942in Faroe Islands
9
Incidence of MS in South Africa
10
Prevalence of MS
11
Unusual Occurrence of MS inTropical Island
12
Risk FactorsUnusual Stress in 2 Yrs Before
Cases Controls p value 79
54 lt0.01
13
Risk factorsExposed to Animal Illness
Cases Controls 43 19
14
Risk FactorsExposed to Canine Distemper
Cases Control 17 6
15
Physical Activity and MS
16
Immunologic Involvement

• Autoantibodies
• Encephalomyelitis developing--Similar to the
  administration of rabies virus vaccine
• Evidence for a superantigen?

17
Frequency of Viral Infection
18
Concordance Rates in Twins
MZ DZ 31/107 13/101 0.29
0.13
19
Prevalence of MS in First Degree Relatives
Sibs Parents Offspring 125/10,682
41/6,521 9/1,521 0.0117 0.0063
0.0059
20
DZ Risk versus Sibling Risk
DZ Sibling 0.13 0.012
21
HLA Antigens and MSNorthern Europeans
22
Conclusions

• MS caused by environmental factors, but not clear
  what they are
• For MS there is evidence for HLA associations,
  however, there is more than HLA
• MS is a multiloci disease