Fig. 3
From: Relationships of serum CC16 levels with smoking status and lung function in COPD
CC16 levels vary by smoking status in COPD (left); CC16 levels are positively correlated with FEV1/FVC among former smokers with COPD (right). A A box and whisker plot depicts distribution of CC16 level across smoking status. The median is represented by a solid line and the box represents the interquartile range, whiskers are the minimum and maximum. Serum CC16 levels in COPD were highest among never smokers, followed by former and current (N = 245, P for trend < 0.0001). B A scatter plot depicts a positive correlation between CC16 level (log) and FEV1/FVC among former smokers with COPD (N = 148, p = 0.0009). r = Pearson correlation coefficient