Solar cycles, geomagnetic effects may be linked to giant cell arteritis, RA incidence

Recorded solar cycles correlated with the onset of giant cell arteritis and rheumatoid arthritis with consistent lag times, according to researchers from Johns Hopkins University, Princeton University and the Mayo Clinic.The researchers studied medical records from Olmsted County, Minn., that included diagnoses of giant cell arteritis (GCA) made between 1950 and 2004 and of rheumatoid arthritis (RA) made between 1955 and 2007 to compute the yearly average as well as the yearly 3-year centered moving average of incident rates. The incidence rates were adjusted for age and sex based on white people living in the U.S. in 2000.