Skip to main content
. 2012 Jul 27;7(7):e42357. doi: 10.1371/journal.pone.0042357

Figure 4. Correlation between NAD+ levels and Age in (A) Males (B) Females.

Figure 4

(A) NAD+ concentrations decline with age in males. NAD+ levels decreased significantly in males aged between 0–77 years (line a; p = 0.0007; n = 27). Pearson's correlation coefficient for a normally distributed population, r = −0.769. The post-pubescent data for male subjects also showed a decline in NAD+ levels with age (line b; r = −0.706; p = 0.0001; n = 19). An exponential (first-order) least squares fit was used to generate the nonlinear trend lines (line a and b). (B) NAD+ concentrations decreased significantly with age (36–76) in post-pubescent females (p = 0.01; n = 22). Pearson's correlation coefficient for a normally distributed population,r = −0.537. An exponential (first-order) least squares fit was used to generate the nonlinear trend line.