Although the use of antiretroviral therapy has been a rousing success in terms of suppressing HIV and enabling people with the virus to live normal or near-normal life spans, the disease may take its toll in the form of the amplification of certain measures of aging. As such, a European study team set out to determine whether having HIV makes people “older” than their chronological age.
The team, led by Davide De Francesco, a research statistician and PhD candidate at the Institute for Global Health, part of University College London, analyzed data on 134 people living with HIV who were taking antiretroviral therapy, 79 HIV-negative controls who were chosen because they had lifestyle factors comparable to the HIV-positive subjects, and 35 blood donors who were free of HIV, hepatitis, syphilis, and other infectious diseases and were matched by age to the HIV-positive and HIV-negative subjects.
The HIV-positive and HIV-negative matched enrollees, all at least 45 years old, were culled from sexual health clinics in London and Amsterdam. Some HIV-negative enrollees were recruited from those same clinics, while others were drawn from community groups, churches, and advertisements. The blood donors came from a blood bank in Amsterdam.
The investigators looked at 10 biomarkers of aging used by a European Union-backed project called the MARK-AGE study.
“The study recruited approximately 3300 subjects aged between 30 and 74 years, from 8 European countries, and collected information on nearly 400 candidate biomarkers of aging, including DNA-based markers, markers of metabolism and oxidative stress,” said Mr. De Francesco in an interview with Contagion®
. “Candidate biomarkers were selected either because they had been already known to correlate with age or they had been shown to be related to aspects of aging.”
From this set of 400 biomarkers, the study team then chose the 10 they felt best revealed how quickly or slowly subjects aged. They then looked at these biomarkers in combination to determine approximately ‘where’ in the subjects’ lifespans they actually were versus how many years they had been alive.
The results? People with HIV may be biologically “older”
than the general population. The study found that the HIV-positive subjects were an average of 13.2 years older than their chronological ages would indicate, while their lifestyle-matched HIV-negative counterparts were an average of 5.5 years older. The age-matched blood donors, however, were an average of 7 years younger biologically than chronologically.
The study’s authors noted that the aging seen in the study subjects was not progressive.
“Whilst HIV-positive individuals report a greater age advancement at study entry, they did not subsequently appear to age at an accelerated rate compared to the HIV-negative controls in the study, suggesting a static 1-time hit attributable to HIV,” said Mr. De Francesco. “This result is more suggestive of an accentuation rather than an acceleration of the aging process due to treated HIV disease. However, in order to more properly assess this hypothesis, we would need longitudinal data to see changes [over] time in the three groups.”
Why are people with HIV biologically older than their real ages would suggest? The study suggests that co-infections
with diseases such as cytomegalovirus and hepatitis, which are common in people with HIV, take a toll on the immune system. Prior exposure to antiretroviral therapy—particularly the drug saquinavir—may cause cell toxicity. However, the subjects’ history of smoking, which is a habit disproportionately practiced by HIV-positive individuals, did not seem to have any impact on age advancement in this study.
Limitations of the study include the possibility of confounders that weren’t taken into account, such as city living vs rural life, diet, level of physical activity, and sleep habits, all of which affect health. Because the subjects were all at least 45 years old, it is unknown whether the results of this study would apply to younger people. The blood donor cohort was comprised of more women than was the case in the other 2 groups, which could have skewed the results as the men in this study showed greater age advancement overall. The researchers also suggested that, due to strict blood-donation requirements in the Netherlands, the blood donors may, in general, have been a fairly robust group.
The study, “Do people living with HIV experience greater age advancement than their HIV-negative counterparts?
,” is published in press in AIDS
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