Læknablaðið - 01.12.1974, Page 35

LÆKNABLAÐIÐ
177
TABLE 16 cont.
Definite and/or probable cases Average annual incidence rate per 100,000
Preva- lence All cases
476 34.7 2.74
127 55.0 2.7
958 41.5
52 128.1
42 21.2
140 39.6
3.2
464 105.0
SUMMARY
Prevalence and incidence studies of multiple
sclerosis have been performed in Iceland over
the 20-year period 1946-1965. Collection of
cases extends over the period 1958-1972. Schu-
macher’s criteria with some modification have
been adhered to. During this period 142 pati-
ents have been encountered of whom 129
were clEissified as definite or probable and 13
as possible. The male-female ratio in definite
and probable cases was 50/79 and in the pos-
sible cases 7/6. The possible cases are mostly
not included in the statistical figures in this
work. The mean age at onset for the period
1946-1955 was 27 years and during the period
1956-1965 32 years. No significant difference
between sexes was found in age of onset.
On December 31 1945 the prevalence was
19.6/100,000 for males, 57.2 for females and
38.4 for both sexes.
Corresponding figures
31 December 1950 were 27.7 64.1 and 45.9
— — 1955 — 39.8 65.7 and 52.7
— — 1960 — 42.8 62.1 and 52.4
— — 1965 — 44.0 60.7 and 52.3
The age specific prevalence rate was highest
in the age groups 30-39 and 40-49 respectively.
The average annual incidence rate per
100,000 population during the period 1946-1955
was 3.1 and during the period 1956-1965 1 9.
There is some hint of decreasing incidence.
Both prevalence and incidence figures com-
pare well with those in European and North-
American surveys with exeeption of studies in
Orkney and Shetland Islands, North-East Scot-
land and Gothenburg, where the figures are
much higher.
The average annual risk rate per 100,000
population during the period 1946-1955 was 5.3
compared with 3.4 in 1956-1965.
There seems to be an accumulation of cases
in Eastern-Iceland. There were 9 families con-
taining more than 1 case and the familial in-
cidence was 7% when ealculated by number
of families, but 14% when calculated by num-
ber of cases.
In about half of the patients the course of
the disease is remarkably benign. During the
years 1946 — October 1 1969, the average
annual death rate in definite and probable
cases was 0.75% for men, 1.16% for women,
and 0.9% for both sexes.
Onset symptoms are in agreement with other
authors. Frequency of bouts during the first
5 years of the disease were higher in the later
period 1956-1965. This can be explained by
more reliable history during that period.
The onset-diagnosis interval was during the
period 1946-1955 12 years, but during the period
1956-1965 it was 5.6 which is in conformity
with most authors. This can be attributed to
less retrospective history. Of the definite and
probable cases 61% had the same birthplace
and onset place and of the rest 17% stayed at
their birthplace to the age of 15. This would
be of some interest as M S is now regarded as
a disease of childhood.
Við þökkum ritara okkar Sigríði Þórarins-
dóttur fyrir vélritun á handritinu og undirbún-
ing þess til prentunar.
HEIMILDIR
1. Ab, L. and Schaltenbrand, G. Statische
Untersuchung zum Problem der Multiplen
Sklerose. Dtsch. Z. Nervenlieilk. 174:199-
218. 1956.
2. Acheson, E. D. Epidemiology of multiple
sclerosis. In: D. McAlpine, C. E. Lumsden
and E. D. Acheson (Eds.), Multiple sclerosis.
A reappraisal, Livingstone, Edinburgh, p
18. 1965.
3. Adams, D. K., Sutherland, J. M. and Flet-
cher, W. B. Early manifestation of dis-
seminated sclerosis. Brit. Med. J. 2:431-436.
1950.
4. Allison, R. S. and Millar, J. H. D. Preval-
ence and familial incidence of disseminated
sclerosis. A report to the Northern Ireland
Hospitais Authority on the result of a throe
year survey. Ulster Med. J. 23 (Suppl. 2).
1954.