The relationship of white cell count, platelet count, and hematocrit to cigarette smoking in adolescents: the Oslo Youth Study.

This article reports on the relationship between cigarette smoking, white blood cell count (WBC), platelet count (PC), and hematocrit in a Norwegian adolescent population. Data were obtained on 439 youths, 14 to 16 years old, as part of the Oslo Youth Study, an investigation of risk factors and behaviors for cardiovascular disease and cancer among adolescents. Analyses of covariance, controlling for height, weight, age, sexual maturation, high-density lipoprotein (HDL) cholesterol, and hematocrit revealed that both male and female regular smokers (those reporting smoking at least once a week) had significantly higher mean WBCs. Male regular smokers also had significantly higher PCs than nonsmokers, and female regular smokers had higher PCs than young women who smoked less often than once a month. Hematocrit, after adjustment for height, weight, age, sexual maturation, and HDL cholesterol, was significantly lower in male regular smokers, while female regular smokers had higher hematocrit values than nonsmokers or occasional smokers. Results of this study show that WBC and PC were increased in adolescents who started smoking relatively recently. This indicates that the increase in white cell count observed in smokers is unlikely to be due to a longstanding smoking-induced chronic disease condition.