Comparative Effects of Cigarette and Hookah Smoking on Oral Microbiota Composition and Blood Indices in Young Adult Males.

Cigarette and hookah smoking remain prevalent worldwide, yet their comparative effects on oral microbiota and hematological parameters are not fully understood. This cross-sectional study investigated these impacts among 87 healthy males (18-40 years) in Sulaymaniyah, Iraq, divided into cigarette smokers, hookah smokers, and non-smokers (n = 29 each). Oral rinses were analyzed for microbial load and species distribution using selective media and standard identification techniques, while venous blood samples were evaluated for complete blood counts using an automated analyzer. Cigarette smokers exhibited the highest oral bacterial load (5.96 ± 0.19 log10 CFU/mL) compared with non-smokers (3.70 ± 0.10; p < 0.001), followed by hookah smokers. Colonization by Candida albicans and Gram-positive cocci (Staphylococcaceae, Streptococcaceae) was more frequent in smokers. Both smoking methods significantly increased RBC count, hemoglobin, and hematocrit levels (p < 0.01). Mean corpuscular volume increased significantly only in cigarette smokers, whereas red cell distribution width and mean platelet volume were significantly higher in hookah smokers (p < 0.01). Exploratory correlation analysis revealed strong positive associations between oral bacterial load and erythrocyte-related parameters (RBC, HGB, HCT; r = 0.91-0.94), while weak correlations were observed with inflammatory and platelet indices (WBC, RDW, MPV). These findings indicate that cigarette and hookah smoking disrupt oral microbial balance and alter hematological parameters, with distinct patterns between smoking types. The observed correlations likely reflect parallel systemic effects of smoking-related toxicants rather than a direct causal link between oral dysbiosis and erythropoiesis. Overall, the results reinforce that hookah smoking is not a safer alternative to cigarette use and highlight the need for targeted public health interventions.