In multivariable stepwise linear regression models, the factors independently associated with walking less in the 6MWT were: older age (56–65 years and > 65 years vs. < 55 years), elevated waist circumference (≥ 102 cm in men and 88 cm in women), NT-pro BNP > 125 pg/mL, C-reactive protein ≥ 3 mg/dL, troponin T ≥ 14 pg/mL, and anemia (hemoglobin < 13 g/dL in men and < 12 g/dL in women) (p < 0.05 for all) Table 2. This evidence concerns the gene NPPB and anemia (phenotype).