Both rheumatoid arthritis (RA) and giant cell arteritis (GCA) are autoimmune conditions in which the body’s own immune system mistakenly attacks the organs and the tissues. RA causes joint swelling, which leads to pain and loss of physical function, and GCA causes headaches, jaw pain, and vision problems as the walls of the arteries become inflamed.
For this study, first author Simon Wing and coauthor Lisa Rider paired physicists and medical researchers together.
First, the physicists compared incidences of RA and GCA with solar cycles, where they found that incidences of both diseases correlated with the sun’s magnetic activity cycle.
Solar cycles can cause dramatic changes to the earth as solar outbursts hurl millions of magnetic and electrical plasmas against the earth’s magnetosphere surrounding the the planet.
The researchers compared incidences of extreme ultraviolet solar radiation during 1950 and 2007 to 1,179 incidences of RA and 207 of GCA. Incidences of both diseases were strongest when solar activity was high. GCA cases peaked within one year of the strongest geomagnetic activity, and RA cases fell during the year of lowest geomagnetic activity.
The researchers did not establish an explanation for the connection, but they did highlight five disease occurrences that could only be explained due to geomagnetic activity.
Uncovering the link of RA and GCA to solar cycles is important as it can aid in detecting susceptible individuals and could help develop strategies to better control RA and GCA during solar cycles.