This was confirmed for CTX by cosinor analyses in both CKD (p = 0.003) and controls (p = 0.002) with an acrophase at around 3 o'clock a.m. (Fig. 2), however, we were unable to find significant rhythmicity for P1NP, osteocalcin, BAP or TRAcP by cosinor analysis. This evidence concerns the gene CYP27A1 and chronic kidney disease.