The association between (A) relative citrate concentration and smoking status, and (B) U-Cd and U-8-oxodG. (A) Normalized citrate levels in never, past and current smokers. ** statistically significant difference to 'never smoked' group, P < 0.01 (Kruskal-Wallis with Mann-Whitney post-test). Correlation coefficient (citrate versus smoking status), ρ = -0.225, P = 0.002 (Spearman's rho). Never smoked n = 108, past smoker n = 35, current smoker n = 32. (B) * statistically significant difference, P < 0.05 (Mann-Whitney test). N = 40, 20 per group. Median values marked with 95% confidence intervals represented as error bars. Data points falling outside these confidence intervals are marked.
Ellis et al. BMC Medicine 2012 10:61 doi:10.1186/1741-7015-10-61