Evidence for a moderating effect of drinking severity but not HIV status on brain age in heavy episodic drinkers

Background Chronic HIV infection and alcohol use have been associated with brain changes and neurocognitive impairment. However, their combined effects are less well studied. We correlated measures of “brain age gap” (BAG) and neurocognitive impairment in participants with and without HIV/AIDS and heavy episodic drinking (HED). We predicted that BAG will be greater in PWH who engage in HED and that these effects will be particularly pronounced in frontoparietal and subcortical regions. Method 69 participants were recruited from a community health centre in Cape Town: HIV-/HED-(N = 17), HIV+/HED- (N = 14), HIV-/HED+ (N = 21), and HIV+/HED+ (N = 17). Brain age gap (BAG) was derived from thickness, area and volumetric measurements from the whole brain or one of six brain regions. Linear regression models were employed to identify differences in BAG between patient groups and controls. Associations between BAG and clinical indicators of HIV and HED status were also tested using bivariate statistical methods. Results Compared to controls, greater whole brain BAG was observed in HIV-/HED+ (Cohen’s d = 1.61, p < 0.001), and HIV+/HED+ (d = 1.52, p = 0.005) participants. Differences in BAG between patients and controls were observed subcortically, as for the cingulate and the parietal cortex. An exploratory analysis revealed that higher relative brain ageing in HED participants with the highest drinking scores (W = 66, p = 0.036) but did not vary as a function of nadir CD4 count or current HIV viral load. Conclusion The association between heavy episodic drinking and BAG, independent of HIV status, points to the importance of screening for and targeting alcohol use disorders in primary care. Our findings also point to the utility of assessing the contribution of brain regions to the BAG.