Assessment of eosinophil-neutrophil ratio, eosinophil-lymphocyte ratio and eosinophil-monocyte ratio in post-reproductive women

Post-reproductive (post-menopausal) changes can alter white blood cell composition, including changes in lymphocyte percentages which controls eosinophil-to-lymphocyte ratio. The eosinophil-to-neutrophil ratio, eosinophil-to-lymphocyte ratio and eosinophil-to-monocyte ratio are new haematological markers that give clinical understanding into conditions like autoimmune disorders, allergies, and cancers. This study aimed to assess eosinophil-to-neutrophil ratio (ENR), eosinophil-to-lymphocyte ratio (ELR) and eosinophil-to-monocyte ratio (EMR) in post-reproductive women. This case–control study was conducted at Enugu State University Teaching Hospital from September 2024 to August 2025, involving 43 post-reproductive women (aged 60–80 years) and 30 sex-matched healthy controls. Total and absolute differential white blood cell count (neutrophils, lymphocytes, monocytes, eosinophils, basophils) was measured using an automated analyzer. The ENR, ELR and EMR were calculated by dividing the eosinophil count by neutrophil count, eosinophil count by lymphocyte count, eosinophil count by monocyte count respectively. Post-reproductive women had significantly increased absolute neutrophil count (5.177 ± 3.640 × 109/L) and absolute monocyte count (0.692 ± 0.208  x 109/L) compared with control (3.327 ± 1.998 x 109/L and 0.449 ± 0.243 x 109/L). There was a positive correlation between absolute eosinophil count and ENR, ELR & EMR (p= < 0.001). In post-reproductive women above 60 years, there was significant increase in neutrophil count and monocyte count and with insignificant difference for the ENR, ELR, EMR, lymphocyte count, eosinophil count and basophil count when compared between case and control group. In addition, eosinophil count had a positive correlation with eosinophil-to-neutrophil ratio, eosinophil-to-lymphocyte ratio and eosinophil-to-monocyte ratio.