Small-scale geographical variation in multiple sclerosis: A case-control study using Danish register data 1971–2013

• Published in: Multiple sclerosis and related disorders Vol. 23; pp. 40 - 45
• Main Authors: Bihrmann, Kristine, Nielsen, Nete Munk, Magyari, Melinda, Koch-Henriksen, Nils, Nordsborg, Rikke Baastrup, Ersbøll, Annette Kjær
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2018
• Subjects: Case-control study; Denmark; Geographical differences; Multiple sclerosis; Registry; Spatial analysis; Spatial analysis; Denmark; Geographical differences; Case-control study; Multiple sclerosis; Registry
• ISSN: 2211-0348; 2211-0356; 2211-0356
• DOI: 10.1016/j.msard.2018.04.021

•Nationwide, register-based study on 12 993 Danish MS cases.•Spatial variation in MS based on residence at birth, age 15, and onset of disease.•High-/low-risk areas had some variation between birth, age 15, onset of disease.•Small-scale geographical variation may suggest local environmental risk factors. The aetiology of multiple sclerosis (MS) is largely unknown, but commonly assumed to be a complex interaction between genes and environmental exposures, presumably during early life. To evaluate the possible importance and timing of environmental exposures we investigated the spatial variation in the risk of MS in Denmark according to residence at birth, age 15, and clinical onset of disease. We carried out a nationwide, register-based case-control study including 12 993 Danish MS cases with onset of disease 1971–2013. Information on exact residential addresses was available for all study subjects in the Danish Civil Registration System. The spatial variation in risk of MS was estimated by kernel regression. We identified spatial variation in the risk of MS according to residence at birth, age 15, and onset of disease. Several high- and low-risk areas were identified across the country with some variation between birth, age 15, and onset. Small-scale geographical variation in the risk of MS suggests that local environmental risk factors could be at play and may be related to life style factors.