GEOMAGNETIC DISTURBANCES MAY BE ENVIRONMENTAL RISK FACTOR FOR MULTIPLE SCLEROSIS: AN ECOLOGICAL STUDY OF 111 LOCATIONS IN 24 COUNTRIES
All previous studies indicate that environmental factor(s) is/are the main cause of the neurological disease of multiple sclerosis (MS). It seems that geomagnetic disturbances (GMD) have the ability to explain special features of MS such as the cause of its relapsing-remitting nature, incidence trends, geografical distribution and the birth time effect. Areas around geomagnetic 60 degree latitude (GM60L) experience the greatest amount of GMD. The easiest way to evaluate our hypothesis was to test the association of MS prevalence (MSP) with “angular distance to geomagnetic 60 degree latitude” (AMAG60) and compare it with the known association of MS with geographical latitude (GL). We did the same with “angular distance to geographic 60 degree latitude” (AGRAPH60) as a control.
English written papers with MSP keywords were retrieved from the PubMed. By meta-regression analyses, relationship of MSP with GL, AMAG60 and AGRAPH60 were evaluated separately. MSP data were weighted by square root of number of prevalent cases. Models were compared by their adjusted R square (AR2) and standard error of estimate (SEE).
111 MSP data were entered in the study. In each continent, AMAG60 had the best correlation with MSP, the largest AR2 and the least SEE. Merging both hemisphere data, AMAG60 explained 56% of MSP variations with the least SEE (R=0.75, AR2= 0.56, SEE= 57), while geographic latitude explained 17% (R=0.41, AR2=0.17, SEE=78.5) and AGRAPH60 explained 12% of those variations with the highest SEE (R=0.35, AR2=0.12, SEE=80.5).
Results confirmed that AMAG60 is the best describer of MSP variations and has the strongest association with MSP distribution. Those clarified that the well-known latitudinal gradient of MSP may be actually a gradient related to GM60L and supported that GMD can be the actual environmental risk factor for MS. We believe that this comprehensive hypothesis deserves to be considered for further validation studies.