Age was negatively correlated with BMAL1 expression only in the moderate IDD group (Grade II: y = –0.414 4x + 100.2, r = 0.334 4, P = 0.030 3; Grade III: y = –0.688 2x + 98.52, r = 0.266, P < 0.000 1; Grade IV: y = –0.085 25x + 44.71, r = 0.002 829, P = 0.689 1; Grade V: y = –0.283 3x + 33.93, r = 0.058 47, P = 0.255 0), suggesting that age as a factor influences the expression of BMAL1 in the early stage of IDD, while other factors, such as abnormal loading, may play a more significant role in the later progression of IDD. Here, BMAL1 is linked to intervertebral disk degenerative disorder.