Age-dependent changes in the association between sleep duration and impaired glucose metabolism

Figure 4 Relationship between HbA1c levels and sleep duration according to age groups divided by decades. Each point and vertical bar represent the mean ± SE. Correlation coefficients and P values of Pearson’s correlation were r = -0.03, P < 0.0001 for the 20s, r = -0.05, P < 0.0001 for the 30s, r = -0.01, P = 0.41 for the 40s, r = 0.01, P = 0.52 for the 50s, and r = -0.01, P = 0.32 for the 60-70s, respectively. The corresponding number of subjects is shown in the side of the bar.