Fig. 2From: Association of plasma mitochondrial DNA with COPD severity and progression in the SPIROMICS cohortPlasma mtDNA levels were higher in subjects with mild/moderate COPD but falls in severe disease. P-mtDNA was measured in SPIROMICS participants, including never smokers (n = 100; red), smokers without airflow obstruction (n = 199; green), participants with mild/moderate COPD (n = 201; blue), and severe COPD (n = 200; purple). Data are presented as median with box indicating upper and lower quartiles, whiskers indicating extrema, and with p-values calculated by Tukey’s range testBack to article page