A low nadir (lowest ever) CD4 cell count is associated
with increased lens density – a marker for cataract formation – in people with HIV, investigators report in the online edition of the Journal of Acquired Immune Deficiency
Syndromes. The authors suggest that increased lens density may be an
indicator of accelerated ageing in people with HIV.
“HIV-infected individuals receiving ART
[antiretroviral therapy] and who had low nadir CD4 cell counts…have a greater risk of increased ocular lens density when compared with HIV-seronegative individuals,”
write the researchers. “This provides corroborative evidence of accelerated
aging and that this may be associated with delayed initiation of ART.”
Improvements in treatment and care mean
that the prognosis of many people with HIV is now excellent. However,
there is accumulating evidence that HIV is associated with acceleration
in the ageing process. Increased rates
of many of the diseases of ageing have been seen in people living with HIV.
The prevalence of cataracts – cloudiness in the lens of the eye – increases with age. It is therefore possible that people with HIV
are vulnerable to cataract formation at an earlier age than would be otherwise
An international team of investigators
wanted to see if this was the case. They therefore designed a study comparing
lens density – an accurate marker of cataract formation – involving 242 people living with HIV and 248 age-matched controls recruited in Cape Town,
All were aged over 30 and none had a
history of serious eye disease or had diabetes, which can lead to ocular
Lens density was measured using
densitometry imaging. This uses a 360-degree rotating non-contact camera that
provides a rapid and precise three-dimensional view of the lens, cornea and
Overall, the patients and controls were
well matched, and had a mean age of approximately 41 years. However, patients
with HIV were less likely to smoke and had lower alcohol consumption than the
controls. Both of these factors have been associated with eye disease.
The majority of HIV-positive patients (88%)
were taking antiretroviral therapy. The median duration of treatment was 59
months. The current median CD4 cell count among the patients taking therapy was
468 cells/mm3 and 84% had an undetectable viral load.
Overall, there was no difference in lens
density measurements between the patients and controls. The median value for
both groups was 9.8.
However, further analysis that took into
account potential confounders, showed that patients on HIV treatment whose
nadir CD4 cell count was below 200 cells/mm3 were more likely to
have high lens density than HIV-negative individuals (p = 0.04).
This association between low nadir CD4 cell
count and increased lens density was also significant when analysis was
restricted to patients with HIV (p = 0.04).
“Low nadir CD4 count has been identified as
an independent predictor of several premature age-related co-morbidities in
HIV-infected individuals,” note the authors.
There was no association between current
CD4 cell count and lens density. However, there was a non-significant trend
suggesting that a detectable viral load despite HIV therapy increased lens
“We found HIV-infected individuals on ART
with low nadir CD4 counts to have an increased risk of higher lens density
compared to HIV-seronegative individuals,” conclude the authors. They suggest
that early initiation of antiretroviral therapy could help prevent the
accelerated ageing observed in people with HIV. “Premature aging may well
have important socio-economic and healthcare implications for the many millions of
people living with HIV long-term on ART in sub-Saharan Africa.”