Association between hemoglobin-to-red blood cell distribution width ratio and abdominal aortic calcification in adults aged ≥40 years: a cross-sectional study based on NHANES 2013–2014 database

Background: Abdominal aortic calcification (AAC) is a well-established predictor of cardiovascular risk. Accumulating evidence indicates that the hemoglobin-to-red blood cell distribution width ratio (HRR) is associated with a range of cardiovascular diseases. However, the relationship between the HRR and AAC among middle-aged and older adults has yet to be explored. Methods: A cross-sectional analysis was performed using data from the National Health and Nutrition Examination Survey 2013–2014. The severity of AAC was quantified using the Kauppila scoring method, carried out through lateral dual-energy X-ray absorptiometry. HRR was calculated by dividing hemoglobin concentration (g/dL) by red blood cell distribution width. Participants were stratified into tertiles according to their HRR values. Multivariate linear and logistic regression models were used to assess the association of HRR with AAC score and the risk of severe AAC, respectively. Results: A total of 3049 participants were included in this study. After adjusting for potential confounders, HRR was significantly inversely associated with AAC scores (β = −1.28; 95% confidence interval [CI]: −2.19 to −0.37; P = 0.006) but not with severe AAC. Compared with participants in the lowest HRR tertile, those in the highest tertile exhibited a reduction in AAC scores of approximately 0.39 units after full adjustment. For severe AAC, a higher HRR was found to be significantly associated with a decreased risk in both the unadjusted model (odds ratio: 0.17; 95% CI: 0.08–0.34; P < 0.001) and the partially adjusted model (odds ratio: 0.28; 95% CI: 0.11–0.73; P = 0.009). However, this association did not persist after full adjustment. Conclusion: These findings suggest an inverse association between higher HRR levels and AAC scores, highlighting its potential role in vascular calcification. HRR may serve as a promising biomarker for assessing the severity of AAC.