SPP1 and Osteopenia: Five types of comparisons were conducted: osteoporosis versus control (OP vs Control), osteopenia versus control (OPN vs Control), osteoporosis versus osteopenia (OP vs OPN), osteoporosis versus non-osteoporosis (OP vs Non-OP; including both OPN and controls), and combined osteoporosis and osteopenia versus control (OP&OPN vs Control; see Figure 3).