Cognitive ageing is premature among a community sample of optimally treated people living with HIV

OBJECTIVES

Evidence of premature cognitive ageing amongst people living with HIV (PLHIV) remains controversial due to previous research limitations including underpowered studies, samples with suboptimal antiretroviral access, varying rate of virological control, high rate of AIDS, over-representation of non-community samples, and inclusion of inappropriate controls. The current study addresses these limitations, while also considering mental health and non-HIV comorbidity burden to determine whether PLHIV showed premature cognitive ageing compared with closely comparable HIV-negative controls.

METHODS

This study enrolled 254 PLHIV [92% on antiretroviral therapy; 84% with HIV RNA < 50 copies/mL; 15% with AIDS) and 72 HIV-negative gay and bisexual men [mean (SD) age = 49 (10.2) years] from a single primary care clinic in Sydney, Australia. Neurocognitive function was evaluated with the Cogstate Computerized Battery (CCB) at baseline and 6 months after. Linear mixed-effects (LME) models examined main and interaction effects of HIV status and chronological age on the CCB demographically uncorrected global neurocognitive z-score (GZS), adjusting for repeated testing, and then adjusting sequentially for HIV disease markers, mental health and comorbidities.

RESULTS

HIV status and age interacted with a lower GZS (β = -0.43, P < 0.05). Higher level of anxiety symptoms (β = -0.11, P < 0.01), historical AIDS (β = -0.12, P < 0.05) and historical HIV brain involvement (β = -0.12, P < 0.05) were associated with lower GZS.

CONCLUSIONS

We found a robust medium-sized premature ageing effect on cognition in a community sample with optimal HIV care. Our study supports routine screening of cognitive and mental health among PLHIV aged ≥ 50 years.

'TB or not TB': the conundrum of pre-European contact tuberculosis in the Pacific

Tuberculosis (TB) is a major global health threat, infecting one-third of the world's population. Despite this prominence, the age, origin and spread of the disease have been topics of contentious debate. Molecular studies suggest that Mycobacterium tuberculosis 'sensu stricto', the most common strain of TB infecting humans today, originated in Africa and from there spread into Europe and Asia. The M. tuberculosis strains most commonly found across the Pacific and the Americas today are most closely related to European strains, supporting a hypothesis that the disease only reached these regions relatively recently via European sailors or settlers. However, this hypothesis is inconsistent with palaeopathological evidence of TB-like lesions in human remains from across the Pacific that predate European contact. Similarly, genetic evidence from pre-European South American mummies challenges the notion of a European introduction of the disease into the Pacific. Here, we review the complex evidence for the age and origin of TB in the Pacific, and discuss key gaps in our knowledge and how these may be addressed. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.