Figure 2. (A) Mean SMI in young, middle-aged and elderly men. (B) Mean SMI in young, middle-aged and elderly women. (C) Mean SMI in young women with normal BMI (18.5-23.9) as well as middle-aged and elderly women. ** P ≤0.01 vs 18-39y, *** P <0.001 vs 18-39y, ### P <0.001 vs 40-59y.