Sirtuin1 (Sirt1), a nicotinamide adenine dinucleotide oxidized (NAD+)-dependent class III deacetylase, regulates the activity of FoxOs, and changes in the levels of Sirt1 expression are associated with the onset of degenerative diseases characterized by increased ROS, including osteoporosis [42, 43]. The gene discussed is SIRT1; the disease is osteoporosis.