Fig. 2
From: Blood levels of nicotinic acid negatively correlate with hearing ability in healthy older men
Correlation between NA (nicotinic acid) levels and hearing thresholds at each frequency. A Correlation of NA levels (μM) with right and left-ear hearing thresholds at each frequency (dB HL). B and C Correlation between NA levels and right-ear hearing thresholds at 1000 Hz (B) and 2000 Hz (C). D-F Correlation between NA levels and left-ear hearing thresholds at 1000 Hz (D), 2000 Hz (E), and 4000 Hz (F). Comparisons were performed using Spearman’s rank correlation coefficient. The correlation coefficients and p-values analyzed excluding outliers are presented in parentheses. *P < 0.05; **P < 0.01; ***P < 0.001