Fig. 5

Correlations between DTI metrics and age. A Despite the higher AD in HIV than SN (regardless of MJ use), the two groups showed similar slopes for age-dependent increases in AD. The AD in the body of the corpus callosum (BCC) is illustrated as an example. B Although HIV+ had lower FA than SN, both groups (regardless of MJ use) showed similar age-dependent declines; see in left anterior limb of the internal capsule (ALIC) FA for example. C Greater age-related declines in the BCC FA were observed in HIV+ individuals, with or without MJ use, than SN subjects (HIV × age-interaction p = 0.037). D, E Compared to all nonusers (blue line), MJ users with or without HIV (dark green line) showed greater age-related declines in FA in left superior longitudinal fasciculus (SLF: MJ × age-interaction p = 0.044) and left external capsule (EC: MJ × age-interaction p = 0.007). F Age-related decline in the right GP_FA was observed in SN-MJ users only (3-way interaction p = 0.02); the other three groups already showed lower levels of FA at younger ages. SN, HIV-seronegative nonuser group; SN + MJ, HIV-seronegative marijuana user group; HIV, HIV-seropositive nonuser group; HIV + MJ, HIV-seropositive marijuana user group