Smoking Status Effect on Inflammatory Markers in a Randomized Trial of Current and Former Heavy Smokers

Abstract

Background. The level of systemic inflammation as measured by circulating levels of C-reactive protein (CRP) and interleukin-6 (IL-6) is linked to an increased risk for cardiovascular diseases (CVD) and cancer. Methods. We recruited 154 current and former smokers between 40 and 80 years of age with 25 or more pack-years of smoking history to study the relationship between inflammatory markers (CRP and IL-6) and smoking status. Results. Our results show that male smokers had significantly higher levels of serum IL-6 compared to male former smokers. We did not find any gender specific differences for smoking and CRP levels but the IL-6 levels were slightly lower in females compared to males. Additionally, our results show that CRP is significantly associated with IL-6 regardless of smoking status. Modelling indicates that the significant predictors of CRP levels were biomarkers of the metabolic syndrome while the significant predictors of IL-6 levels were age and plasma triglycerides among former smokers and the numbers of smoked packs of cigarettes per year among smokers. Conclusions. In conclusion, our study showed that CRP levels were not associated with markers of smoking intensity. However, IL-6 levels were significantly associated with smoking especially among current smokers.

Smoking cessation reduces ratio of total cholesterol/high density lipoprotein (HDL) cholesterol levels on adult people in Yogyakarta Special Region

“…21,26,27 as well in reduced systemic inflammation marker IL-6. 28 In our study, no significantly different in serum CRP level between smoker, former smoker and non-smoker due to the high biological variability (high standard deviation) was observed. This result was also observed in other studies.…”

“…This result was also observed in other studies. 16,28,29 However, although statistically the serum CRP level was not significantly different, it tended to be higher in smoker compared to former smoker and non-smoker. It was indicated smoker is still in higher inflammation state.…”

Longitudinal Impact of Smoking and Smoking Cessation on Inflammatory Markers of Cardiovascular Disease Risk

“…In some population-based studies, active cigarette smoking has been associated with elevated levels of each of the 6 inflammatory markers we investigated; 19–23,25–27 however, these studies have had conflicting results, especially for the most commonly studied markers, CRP 20,23 and WBC count. 20,25 These discrepant findings may have been due to the evolution of the population of smokers, imprecise assessment of smoking status and burden, and changes in laboratory measurement technology over time.…”

“…21,22 However, no studies that we are aware of have investigated the longitudinal effects of smoking cessation and continued smoking on inflammatory markers associated with CVD risk. 20,23 Furthermore, the observational studies published to date have had important limitations: some were small, they often did not adjust for confounders that affect inflammatory marker levels ( i.e., age, sex, adiposity, insulin resistance), did not study newer inflammatory markers, and importantly, participants likely were not representative of contemporary smokers who tend to be more overweight than historical cohorts. 24 …”

Mediastinal and Subcutaneous Chest Fat Are Differentially Associated with Emphysema Progression and Clinical Outcomes in Smokers

“…IL-6 and C-reactive protein (CRP) values were natural logtransformed and their association with baseline BMI, subcutaneous fat, mediastinal fat, and outcomes was assessed by multivariate linear regression modeling with adjustments for age, current smoking status, and appropriate covariates as noted above [22]. Path analysis, a subset of structural equation modeling, is a statistical technique useful for assessing complex interactions between different variables on an outcome [23].…”