Dose-dependent Effects of Cigarette Smoke on Blood Biomarkers in Healthy Japanese Volunteers: Observations from Smoking and Non-smoking

Cigarette smoking is one of the avoidable causes for diseases such as lung cancers, but biomarkers for health condition by cigarette cessation are expected. Biochemical data in plasma from 3053 Japanese in Tokyo were investigated who underwent an annual health check-up from 2003 to 2007 with amount and duration of cigarette smoking. Dose-dependent effects of cigarette smoking as indicated by Brinkman index (daily number of cigarettes × years) were observed on increased circulating white blood cell counts in men and women, red blood cell in women, and plasma triglycerides concentrations in men. Higher levels of hemoglobin and hematocrit in females were seen with ≤ 400 of Brinkman index, but these increases were observed in the male group with ≤ 800 of index. Decreased high-density lipoprotein cholesterol levels in blood were seen in men (> 800 of index). Decreased low-density lipoprotein cholesterol levels and enhanced glucose levels were only seen in a pooled heavy smoker group. Since increased ratios for the white blood cell counts in men and women by cigarette smoking were high among the markers tested in this study, the recovery of these parameters by cigarette cessation was investigated. The white blood cell counts were recovered time-dependently after quitting smoking for 1-3 years as evident with 38 other former smokers. These results suggest white blood cell counts would be sensitive biomarkers for smoking exposures and time-dependent recovery in hearty volunteers in monitoring and educating cigarette smoking and cessation.