How does geomagnetic disturbances affect MS incidence? I haven't a clue. #MSBlog #MSResearch
"I don't know what to make of the data below? These Iranian investigators' have linked MS incidence (new cases) in Iran and Greece with geomagnetic disturbances (GMD) with a one or two year lag. The correlation coefficients are very high. The obvious question is how does geomagnetic disturbances interact with the immune system and the MS causal pathway? Can magnetic fields affect immune function? The author's correctly point out that association does not imply causation. Maybe GMD affect the environment in other ways that are linked to causation; could the affect viral pandemics or sun exposure? What is hard to reconcile is that MS causation probably begins in utero and MS begins many years before the clinical onset of disease or the diagnosis of the disease. I think as a starter we need to ask other countries with good incidence databases to reproduce this data. If this is reproducible we then need to ask how does geomagnetic disturbances interact with the macro (population) and micro-environment (individual) to affect MS causation. Any ideas? Iran is also a country with an odd demographic; they have a very population waist due to rapid rise in fertility 30-odd years ago and this waist is now passing through the MS at-risk period. Therefore a proportion of the increasing MS incidence may simply represent background demographic or population trends. Population demographics does not explain the effect of GMD on MS incidence. The other possibility is that the correlation is purely by chance. There is a website dedicated to spurious correlations; it is worth looking at some of the examples on this site. "
BACKGROUND: Recently, we introduced solar related geomagnetic disturbances (GMD) as a potential environmental risk factor for multiple sclerosis (MS).
AIM: The aim of this study was to test probable correlation between solar activities and GMD with long-term variations of MS incidence.
METHODS: After a systematic review, we studied the association between alterations in the solar wind velocity (VSW) and planetary A index (AP, a GMD index) with MS incidence in Tehran and western Greece, during the 23(rd) solar cycle (1996-2008), by an ecological-correlational study.
RESULTS: We found moderate to strong correlations among MS incidence of Tehran with VSW (rS = 0.665, P = 0.013), with 1 year delay, and also with AP (rS = 0.864, P = 0.001) with 2 year delay. There were very strong correlations among MS incidence data of Greece with VSW (r = 0.906, P < 0.001) and with AP (r = 0.844, P = 0.001), both with 1 year lag.
CONCLUSION: It is the first time that a hypothesis has introduced an environmental factor that may describe MS incidence alterations; however, it should be reminded that correlation does not mean necessarily the existence of a causal relationship. Important message of these findings for researchers is to provide MS incidence reports with higher resolution for consecutive years, based on the time of disease onset and relapses, not just the time of diagnosis. Then, it would be possible to further investigate the validity of GMD hypothesis or any other probable environmental risk factors.