The Association Between Red Cell Distribution Width and Grip Strength in Older Adults

Background The red cell distribution width (RDW), an index of variation of erythrocyte volume (anisocytosis), has traditionally been used in the differential diagnosis of anemia. However, recent studies reported that increased RDW may be associated with adverse aging-related health outcomes. Methods The present cross-sectional study analyzed data from the National Health and Nutrition Examination Survey to examine the association between RDW categories (≤ 13.0%, 13.1 - 14.0%, 14.1 - 15.0%, ≥ 15.1%) and maximum grip strength (GS) (kg) in a nationally representative sample of adults aged 60 years and older. Anemia was defined according to the WHO criteria as a hemoglobin concentration of < 13 g/dl in men and < 12 g/dl in women. Results A total of 2,955 participants with a mean age of 69.3 years represented the study sample. General linear models demonstrated that men and women with RDW ≥ 15.1% were 3.2 kg and 1.4 kg weaker than their counterparts with RDW ≤ 13.0%, respectively. Notably, non-anemic older men in the highest RDW category had a mean GS 3.9 kg lower than those in the lowest RDW category. In contrast, this association was attenuated in women without anemia. Conclusion RDW was inversely associated with GS, particularly in older men. Moreover, this association remained unchanged even among men without anemia.