Fig. 5
From: Relationships of serum CC16 levels with smoking status and lung function in COPD
Correlations between CC16 level and pack-years smoked (former and current smokers with COPD) and years since last smoked (former smokers) with COPD. A Scatter plot demonstrates correlations between CC16 level (log), and pack years smoked for current (N = 73) and former smokers (N = 148) with COPD. There is no statistically significant correlation between serum CC16 levels and pack-years smoked among current smokers with COPD (p = 0.66). There is a significant inverse relationship between pack-years smoked and CC16 levels among former smokers with COPD (r = − 0.2, p = 0.03); CC16 levels decline as pack-years smoked increase. B Scatter plot depicts serum CC16 levels are positively correlated with years since last smoked among former smokers with COPD. r = Pearson correlation coefficient