Elevated blood eosinophil (bEOS) counts are markers of inflammation associated with poorer outcomes in individuals with asthma and chronic obstructive pulmonary disease (COPD).

A new study published in The Journal of Allergy and Clinical Immunology aimed to determine the association between individual characteristics and bEOS counts in individuals with asthma, COPD and non-asthma/COPD controls.

This study selected participants of National Health and Nutrition Examination Surveys (NHANES; 2001-2016) aged ≥18 years who had asthma or COPD and non-asthma/COPD controls. Associations between bEOS counts and age, sex, race/ethnicity, body mass index (BMI) and smoking status were investigated.

The findings revealed that bEOS counts were significantly higher in individuals with asthma than in non-asthma/COPD controls; otherwise, there was no significant difference between the two groups. While the median bEOS counts were consistently higher in men and in those with higher BMI, and lower in individuals of black race. On the other hand, bEOS counts increased with age in non-asthma/COPD controls, but not in individuals with asthma or COPD. Among non-asthma/COPD controls and in individuals with asthma, bEOS counts were higher in current and former smokers compared to those who never smoked, but no such association was found between bEOS counts and smoking status in individuals with COPD.

In inference, it was stated that among individuals with asthma or COPD, sex, race and BMI should be considered when interpreting bEOS counts. In addition, smoking history should also be interrogated in individuals with asthma.