Association between hemoglobin-to-red blood cell distribution width ratio and cognitive impairment in elderly Americans.

This study aimed to investigate the potential association between the hemoglobin-to-red blood cell distribution width ratio (HRR) and cognitive impairment in a representative sample of elderly Americans. Data from National Health and Nutrition Examination Survey 1999 to 2002 were utilized to analyze demographic information, cognitive function assessments, and laboratory data. Binary Logistic regression was conducted to analyze the associations. Subgroup analyses and sensitivity analyses were performed simultaneously. In the univariable logistic regression analysis, the odds ratio was 0.13 (95% confidence interval [CI]: 0.06-0.25; P < .001). After adjusting for all covariates in the multivariable regression analysis, the odds ratio was 0.25 (95% CI: 0.11-0.6; P = .002). Compared to the lowest HRR group, the higher HRR groups had significantly lower odds of cognitive impairment: Q2 (OR = 0.6, 95% CI: 0.42-0.84, P = .003), Q3 (OR = 0.54, 95% CI: 0.37-0.77, P = .001), and Q4 (OR = 0.56, 95% CI: 0.38-0.82, P = .003). Subgroup and sensitivity results were stable and consistent. These results suggest that higher levels of HRR may be associated with a lower risk of cognitive impairment in elderly Americans.