Smoking-induced leukocytosis can persist after cessation of smoking.

BACKGROUND

Associations between smoking and leukocytosis or elevated hemoglobin concentrations in the blood need to be validated using multivariate analysis.

METHODS

A total of 2,511 male subjects aged 25-62 years participated in an annual health examination held at their workplace. The relationship between white blood cells (WBC) and hemoglobin (Hb) levels in blood and smoking status was then evaluated using a cross-sectional survey and multiple logistic regression analysis. Age, body mass index (BMI), smoking and drinking status, diastolic blood pressure, and physical activity were used as covariate factors.

RESULTS

Odds ratios (ORs) and 95% confidence intervals (95% CIs) of WBC of >9,000 counts/mm3 of total blood for current smokers and ex-smokers with a period of 5-9.9 years since smoking cessation vs. that of nonsmokers were 12.1 (7.0-21.0) and 3.8 (1.2-12.0), respectively. OR (95% CI) of Hb level >16 g/dL of total blood for current smokers vs. nonsmokers was 1.6 (1.1-2.3). Significant ORs for elevated Hb level in total blood were also observed for age (OR, 1.0; 95% CI, 0.9-1.0), BMI >25 (OR, 2.2; 95% CI, 1.6-3.1), and diastolic blood pressure of >90 mmHg (OR, 2.2; 95% CI, 1.5-3.2).

CONCLUSIONS

Current smoking is associated with increase in WBC count and Hb levels in total blood, the former relationship recognized in subjects who have stopped smoking for 5-9.9 years. Obesity and aging are inversely related with Hb level in blood.