Association of Smoking Status and Complete Blood Count Parameters among Adults in Central India: A Cross-Sectional Comparative Study

Background: Complete blood count (CBC) indices are widely available, but their associations with smoking among rural Indian adults remain insufficiently characterized. Objective: To compare CBC parameters between smokers and non-smokers in Central India and examine their associations with cumulative smoking exposure. Methods: This community-based, frequency-matched cross-sectional comparative study included 200 daily bidi and/or cigarette smokers and 200 never-smokers aged 20–65 years. Groups were frequency-matched by age, sex, and residential sub-district. EDTA blood samples were analyzed within 4 hours using an automated hematology analyzer. Group comparisons used independent-sample t-tests or Mann–Whitney U tests. Multivariable linear regression adjusted for age, sex, body mass index, alcohol consumption, and occupational status. Results: Smokers had higher total white blood cell (WBC) counts (8.39 ± 1.68 ×10⁹/L versus 6.35 ± 1.42 ×10⁹/L), hemoglobin (15.2 ± 1.4 versus 13.8 ± 1.3 g/dL), hematocrit (46.1 ± 3.8% versus 42.2 ± 3.2%), and mean corpuscular volume (MCV; 91.4 ± 5.2 versus 86.2 ± 4.8 fL); all p < 0.001. Neutrophil and lymphocyte counts were also higher (both p < 0.001). Platelet counts did not differ significantly (242 ± 58 ×10⁹/L versus 251 ± 62 ×10⁹/L; p = 0.142), whereas mean platelet volume was higher in smokers (10.4 ± 1.1 fL versus 9.5 ± 0.9 fL; p < 0.001). Pack-years were positively associated with WBC count (B = 0.112), hemoglobin (B = 0.084), MCV (B = 0.215), and MPV (B = 0.041) after adjustment (all p < 0.001). Conclusion: Smoking was associated with differences in erythrocytic, leukocytic, and platelet indices in this rural Central Indian cohort. Smoking history should be considered when interpreting CBC results. The cross-sectional design does not establish causality.