Pulmonary functional parameters and blood cotinine level in chronic obstructive pulmonary disease.

INTRODUCTION

Smoking is the leading cause of chronic obstructive pulmonary disease (COPD) and cotinine is reliable marker of tobacco exposure. We aimed to investigate the relationship between pulmonary function tests (FVC%, FEV1, FEV1/FVC and FEF25-75%), smoking history and blood cotinine levels in healthy volunteers as a control and patients who have COPD in our study.

MATERIALS AND METHODS

One hundred and two COPD patients and 106 healthy volunteers who admitted to our institution were included. Spirometric investigations of the patients and volunteers were performed. A simple, rapid and reliable gas chromatography-mass spectrometry (GC-MS) method was used for determination of cotinine levels in blood samples.

RESULT

The cut-off value of cotinine was determined as 41.12 ng/mL (97.2% sensitivity and 100% specificity). A significant relationship was observed between average pack-year and cotinine level in current smoker group (p< 0.05). The mean cotinine levels were 6.1, 8.8, and 467.0 ng mL-1 in never smokers, ex-smokers and current smokers, respectively. No relationship was observed between cotinine level and FVC%, FEV1% and FEV1/FVC (p> 0.05). In patient group, there was also no relationship between FEF25-75% and cotinine level however, in control group-smokers a negative correlation was found (p< 0.05; r= -0.372).

CONCLUSIONS

We observed once again with our study that cotinine is a reliable marker of tobacco exposure. The most obvious result is the negative correlation between FEF25-75% value and cotinine level and this result may be caused by the effect of smoking in the peripheral airways at early stages of COPD.