Which Environmental Factor Is Correlated with Long-Term Multiple Sclerosis Incidence Trends: Ultraviolet B Radiation or Geomagnetic Disturbances?

Figure 4

The Shetland Islands data. Panel (a): annual average of the received UV (1958–85). Panel (b): MS incidence of the Shetland Islands (1938–85), adapted from the report of Cook et al. [13]. Panel (c): annual average of global GMD based on the index (1938–85). Panel (d): the result of lagged correlation between received UV and MS incidence. Panel (e): the result of lagged correlation between GMD and MS incidence. The dashed lines in those panels (d and e) are the threshold for significant correlation. The horizontal solid lines in these panels indicate coefficient of correlation .