Red cell distribution width, anemia, and lower-extremity physical function among rural-dwelling older adults

BACKGROUND: Elevated red cell distribution width (RDW) has been associated with degenerative conditions in aging. AIMS: We aimed to evaluate the associations of RDW and anemia with lower-extremity physical function among rural-dwelling older adults. METHODS: This population-based cross-sectional study included 5093 rural residents (age ≥ 60 years, 57.3% women) who participated in the MIND-China Study in Shandong. Data were collected via face-to-face interviews, clinical examinations, and laboratory tests. RDW was categorized according to quartiles and the lower-extremity physical function was assessed using the Short Physical Performance Battery (SPPB), RESULTS: Multiple linear regression analyses suggested that the fourth quartile of RDW (vs. first quartile) was associated with lower SPPB summary score (β-coefficient – 0.38; 95% CI – 0.58 to – 0.18) and lower scores in balance test (– 0.09; – 0.17 to – 0.01), chair stand test (– 0.17; – 0.27 to – 0.07), and walking speed test (– 0.12; – 0.19 to − 0.05). Anemia was associated with a multiple-adjusted β-coefficient of – 0.34 (– 0.52 to – 0.16) for SPPB summary score. Stratified analysis by anemia showed that there was a linear association between RDW and SPPB in individuals without anemia but a J-shaped association in individuals with anemia. DISCUSSION: This large-scale population-based study revealed the associations of high RDW and anemia with poor lower-extremity physical function among rural-dwelling Chinese older adults. These findings suggest that an elevated RDW might be a biochemical marker for poor lower-extremity physical function among older adults. CONCLUSIONS: Anemia and an elevated RDW are associated with poor performance in lower-extremity physical function among rural-dwelling Chinese older adults.