Fig. 1
From: Respiratory viral infections and the risk of rheumatoid arthritis
Incident rheumatoid arthritis trends in 2012 and 2013. The x-axis represents the study period from 2012 to 2013. Because respiratory virus data (exposure) are provided weekly, the number of incident RA cases (outcome) is also represented weekly from the first week of January 2012 to the last week of December 2013. The y-axis represents the weekly number of incident RA cases in each week