Background:
Oxidative stress is induced by tobacco smoking and is also associated with COPD. Malondialdehyde (MDA) has become one of the most used biomarkers that can evaluate the effects of oxidative stress.

Objective:
This study corelated tobacco use and COPD with oxidative stress markers useful in clinical practice.

Methods:
Oxidative stress was evaluated according to the biological variables in 51 (smoking/non-smoking /ex-smoking) patients diagnosed with COPD in different stages of the disease. Smoking status was quantified in pack-years (PYs) in the case of smoker/ ex-smoker patients. Other useful parameters assessed are: serum total cholesterol, triglycerides, low density lipoproteins (LDLChol), high density lipoproteins (HDL-Chol), glucose and lactate dehydrogenase (LDH).

Results:
In the case of smokers, the descriptive analysis showed a mean concentration value for MDA of 2.83 μmol/L (range: 1.69–5.55) that was much higher than the mean concentration in the case of non-smoking patients (2.03 μmol/L; range: 0.7–2.77). A positive correlation was observed between serum concentrations of MDA and triglycerides (r=0.31, p<0.05), MDA and LDH (r=0.5, p<0.05). Based on the statistical results, it can be concluded that MDA (F=3.35, p=0.042), triglycerides (F=2.83, p=0.09) and PY (F=27.12, p=0.0001) were the factors of highest importance for the discrimination of the three groups considered (smokers/ non-smokers/ex-smokers). Lower concentrations of uric acid were found in smokers (mean concentration=5.47 mg/dL) versus non-smokers (mean concentration=6.61 mg/dL), suggesting a decreased endogenous production.

Conclusions:
The discriminatory analysis of smokers showed a direct correlation between MDA concentrations and the intensity of smoking. The findings of this study suggest that smoking is associated with lipid peroxidation and antioxidant response in COPD patients.