While reduced circulating sclerostin has been shown in the first week of GC treatment [33], serum sclerostin and Dkk-1 levels have been found to significantly increase after 1 week of GC treatment and decrease afterwards [32]; recently, a reduction of Dkk-1 and sclerostin levels has been shown in early RA patients after 4 weeks of GC treatment [34]. Here, DKK1 is linked to rheumatoid arthritis.