Is Geo-Environmental Exposure a Risk Factor for Multiple Sclerosis? A Population-Based Cross-Sectional Study in South-Western Sardinia.
BACKGROUND
South-Western Sardinia (SWS) is a high risk area for Multiple Sclerosis (MS) with high prevalence and spatial clustering; its population is genetically representative of Sardinians and presents a peculiar environment. We evaluated the MS environmental risk of specific heavy metals (HM) and geographical factors such as solar UV exposure and urbanization by undertaking a population-based cross-sectional study in SWS.


METHODS
Geochemical data on HM, UV exposure, urbanization and epidemiological MS data were available for all SWS municipalities. Principal Component Analysis (PCA) was applied to the geochemical data to reduce multicollinearity and confounding criticalities. Generalized Linear Mixed Models (GLMM) were applied to evaluate the causal effects of the potential risk factors, and a model selection was performed using Akaike Information Criterion.


RESULTS
The PCA revealed that copper (Cu) does not cluster, while two component scores were extracted: 'basic rocks', including cobalt, chromium and nickel, and 'ore deposits', including lead and zinc. The selected multivariable GLMM highlighted Cu and sex as MS risk factors, adjusting for age and 'ore deposits'. When the Cu concentration increases by 50 ppm, the MS odds are 2.827 (95% CI: 1.645; 5.07) times higher; females have a MS odds 2.04 times (95% CI: 1.59; 2.60) higher than males.


CONCLUSIONS
The high frequency of MS in industrialized countries, where pollution by HM and CO poisoning is widespread, suggests a relationship between environmental exposure to metals and MS. Hence, we suggested a role of Cu homeostasis in MS. This is a preliminary study aimed at generating hypotheses that will need to be confirmed further.
Department of Public Health, Experimental and Forensic Medicine, Unit of Biostatistics and Clinical Epidemiology, University of Pavia, Pavia, Italy.
Maria Cristina
http://orcid.org/0000-0003-1586-527X
MC
Monti
Department of Public Health, Experimental and Forensic Medicine, Unit of Biostatistics and Clinical Epidemiology, University of Pavia, Pavia, Italy.
Davide
D
Guido
Department of Public Health, Experimental and Forensic Medicine, Unit of Biostatistics and Clinical Epidemiology, University of Pavia, Pavia, Italy.
Cristina
C
Montomoli
Department of Public Health, Clinical and Medical Science, University of Cagliari, Cagliari, Italy.
Claudia
C
Sardu
Department of Civil-Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.
Alessandro
A
Sanna
Department of Civil-Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.
Salvatore
S
Pretti
Department of Public Health, Clinical and Medical Science, University of Cagliari, Cagliari, Italy.
Lorena
L
Lorefice
Department of Medical Science, University of Cagliari, Cagliari, Italy.
Maria Giovanna
MG
Marrosu
Department of Civil-Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.
Paolo
P
Valera
Department of Public Health, Clinical and Medical Science, University of Cagliari, Cagliari, Italy.
Eleonora
E
Cocco
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