Epidemiology of multiple sclerosis in the county of Vestfold, eastern Norway: incidence and prevalence calculations.
The county of Vestfold in the South-eastern part of Norway has undergone two incidence and prevalence surveys on multiple sclerosis. The prevalence of definite/probable MS on January 1, 1963 was 61.6/100,000. Based on the same diagnostic criteria, the present study reports a slight increase in prevalence to 86.4/100,000 on January 1st 1983. The average annual incidence was calculated for 5 years periods from 1953 to 1983. The time periods 1953-1962 and 1973-1977 showed age-adjusted incidence rates between 4.50 and 5.49/100,000 while the 10-year period 1963-1972 showed significantly lower rates. The fluctuating pattern of MS incidence and prevalence over time supports the view that MS is not a stable disease, and that exogenous factors are influencing the disease pattern.
Edland
A
A
Department of Neurology, Central Hospital of Buskerud, Drammen, Norway.
Nyland
H
H
Riise
T
T
Larsen
J P
JP
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002980:Climate; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D005260:Female; D005843:Geography; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D009460:Neurologic Examination; D009664:Norway / Q000453:epidemiology; D012306:Risk