Table 1 shows baseline demographics and laboratory data classified by lumbar BMD group (normal, n = 57; osteopenia, n = 27; osteoporosis, n = 11). Advanced age (p = 0.001), low body height (p = 0.002), low pre- and post-HD body weight (p < 0.001), low BMI (p = 0.008), small waist circumference (p = 0.005), low serum TG level (p = 0.027), high serum ALP level (p = 0.022), high URR (p = 0.009), high Kt/V (p = 0.015), and high serum FGF21 level (p < 0.001) were found to be associated with lower lumbar T-score. The gene discussed is FGF21; the disease is Osteopenia.