Multiple sclerosis in Nord-Trøndelag County, Norway: a prevalence and incidence study.
OBJECTIVE
To calculate the prevalence and incidence of multiple sclerosis (MS) in Nord-Trøndelag County, Norway.


METHODS
The study comprised everyone diagnosed with MS according to the Poser criteria. On 1 January 2000 a total of 208 were identified: 130 women (62.5%) and 78 men (37.5%). We calculated the crude and age-adjusted annual incidence rates from 1974 to 1999.


RESULTS
The prevalence on 1 January 2000 was 163.6 of 100,000, 204.8 of 100,000 for women and 122.6 of 100,000 for men. The age-adjusted annual incidence increased from 3.9 to 5.6 per 100,000 from 1974 to 1999; women from 4.6 to 6.3 and men from 2.2 to 4.4. After 1984, the incidence among women increased most, peaking at 10.2 per 100,000 in 1984-88.


CONCLUSIONS
MS incidence is increasing in Nord-Trøndelag County. The prevalence is among the highest ever in Norway.
Dahl
O P
OP
Department of Neurology, Namsos Hospital, Namsos, Norway. ole.petter.dahl@hnt.no
Aarseth
J H
JH
Myhr
K M
KM
Nyland
H
H
Midgard
R
R
D000328:Adult; D017677:Age Distribution; D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D017678:Sex Distribution