Insomnia remission in the CBT-I group was associated with the greatest difference in p16INK4a expression values over time, such that those enrolled in the CBT-I who had full remission of insomnia exhibited a significant decrease in p16INK4a by 24 months, a significant change from baseline in this group (P = 0.02). This evidence concerns the gene CDKN2A and insomnia.