Oxidative stress, obesity and chronic inflammation in smokers according to smoking duration and heaviness

Abstract

Background: Smoking and obesity are rising worldwide in an epidemic manner being common risk factors associated with the increase in the overall mortality. Smoking generates oxidative stress and chronic inflammation in the lungs, and the same mechanisms are involved in the pathogenesis of obesity.

Aim: To assess the relationship between cigarette smoking, spirometry parameters and some anthropometric and inflammatory variables, as well as their association with the levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx).

Methods: We performed a cross-sectional study of 94 smokers without any chronic diseases (mean age 52.7±6.4 years), divided into four groups according to their pack years. We performed a questionnaire, anthropometry, spirometry and biochemical tests. The erythrocyte activities of cellular SOD and GPx were measured.

Results: We found that pack years correlated positively with body mass index (BMI) (p=0.002, r=0.323), waist circumference (WC) (p<0.0001, r=0.418), C-reactive protein (CRP) (p=0.023, r=0.242) and negatively with FEV₁ (p=0.047, r= -0.205). BMI and WC were significantly associated with CRP. GPx concentrations were influenced by BMI (p=0.017, β= -0.358) and the number of cigarettes smoked per day (p=0.025, β= -0.398). SOD was also negatively influenced by BMI and WC (p<0.05 for both). FEV₁ was related negatively with WC (p=0.047, β= -0.31).

Conclusion: There is an increased oxidative stress and chronic inflammation in heavy smokers with long smoking history. These processes are closely linked with obesity, which along with smoking increase the risk of early decline in lung function.