Multiple sclerosis in Northern Norway, epidemiology and comorbidity

Background: Multiple sclerosis (MS) is a severe chronic inflammatory disease in the central nervous system, mainly affecting young adults. The prevalence varies between different parts of the world, but the general rule is that it increases with increasing latitude. Studies on comorbid conditions in...

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Bibliographic Details
Main Author: Benjaminsen, Espen
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: UiT The Arctic University of Norway 2022
Subjects:
Online Access:https://hdl.handle.net/10037/24720
Description
Summary:Background: Multiple sclerosis (MS) is a severe chronic inflammatory disease in the central nervous system, mainly affecting young adults. The prevalence varies between different parts of the world, but the general rule is that it increases with increasing latitude. Studies on comorbid conditions in MS are limited, but this topic have gained increasing interest. Aims: To describe the occurrence of MS in Nordland County, and explore the extent to which the number of registered cases of MS in the Norwegian Patient Registry (NPR) corresponds to the actual number of MS patients in the county. To study the occurrence of comorbid conditions in the same MS population. Methods: Cross-sectional and longitudinal studies with the use of the electronic medical record system at the Nordland Hospital Trust in Bodø combined with data from the NPR. Results: The average yearly incidence per 100 000 was 0.7 during the period 1970 – 1974 and 10.1 in the period 2005 – 2009. The prevalence was 270.5 per 100 000 as of January 1, 2017. For an individual with MS to be correctly registered in the NPR, the sensitivity was 0.97, and for an individual in the NPR to have MS the positive predictive value was 0.92. The Cohen’s kappa was 0.94. The prevalence of active epilepsy was 3.2 % in those with MS living in the county as of January 1, 2010. In the MS patients correctly registered in the NPR as of January 1, 2017, epilepsy was found in 2.8 %, inflammatory bowel disease in 1.3 % and non-melanoma skin cancer in 1.7 %. Conclusion: The occurrence of MS has been increased during the whole period from 1970 to 2017, and the prevalence in Nordland is now as high as in southern regions of Norway. The number of MS patients in Nordland registered in the NPR corresponds well with the actual number of MS patients in the county. The prevalence of epilepsy, inflammatory bowel disease and non-melanoma skin cancer is increased compared to what is found in the general Norwegian population. Bakgrunn: Multippel sklerose (MS) er en alvorlig kronisk inflammatorisk sykdom i sentralnervesystemet, som i hovedsak rammer unge voksne. Prevalensen varierer mellom ulike deler av verden, men hovedregelen er at den øker med økende breddegrad. Komorbide tilstander ved MS har vært forholdsvis lite studert, men dette har fått økende interesse i løpet av de siste årene. Mål: Å beskrive forekomsten av MS i Nordland, og undersøke i hvilken grad tallene for registrerte tilfeller av MS i Norsk Pasient Register (NPR) samsvarer med det reelle antall MS pasienter i fylket. Undersøke forekomsten av komorbide tilstander i MS populasjonen. Metode: Tverrsnitts- og longitudinelle studier gjort ved bruk av Nordlandssykehusets elektroniske journalsystem kombinert med data fra NPR. Resultater: Den gjennomsnittlige årlige insidensen per 100 000 var 0.7 i perioden 1970-1974 og 10.1 i perioden 2005-2009. Prevalensen var 270.5 per 100 000 den 1. januar 2017. Sensitiviteten for at en person med MS skal være korrekt registrert i NPR var 0.97, og den positive prediktive verdien for at en person registrert i NPR faktisk har MS, var 0.92. Cohens kappa var 0.94. Prevalensen av aktiv epilepsi var 3.2 % blant MS pasientene bosatt i fylket 1. januar 2010. Av MS-pasientene som var korrekt registrert i NPR 1. januar 2017, hadde 2.8 % epilepsi, 1.3 % hadde inflammatorisk tarmsykdom og 1.7 % hadde non-melanom hudkreft. Konklusjon: Forekomsten av MS har vært økende i hele perioden fra 1970 til 2017, og prevalensen i Nordland er nå like høy som i områder sør i Norge. Antall MS-pasienter i Nordland registrert i NPR samsvarer godt med det reelle antallet MS-pasienter i fylket. Prevalensen av epilepsi, inflammatorisk tarmsykdom og non-melanom hudkreft er økt sammenlignet med hva man finner i den generelle norske befolkningen.