Vitamin D insufficiency is associated with poorer CD4 cell recovery among women who start HIV treatment late, US
investigators report in the online edition of AIDS. After taking into account factors such as viral load, the
authors found a significant relationship between low levels of vitamin D and
impaired immune reconstitution.
“Our study found that vitamin D
insufficiency is associated with late CD4 recovery after HAART [highly active
antiretroviral therapy] initiation,” comment the investigators.
Vitamin D has an important role in overall
health. Deficient levels have been linked to immune dysfunction, cardiovascular
disease, impaired control of infections and depression.
Several studies have found a high
prevalence of vitamin D deficiency in people with HIV. Moreover, research
conducted in HIV-positive men starting antiretroviral treatment late found that
low levels of the vitamin were associated with impaired immune reconstitution.
Investigators from the Women’s Interagency
HIV Study (WIHS) wanted to see if this was also the case in HIV-positive women.
They therefore designed a study involving
204 women who initiated HIV therapy when their CD4 cell count was below 200
cells/mm3. The investigators examined the relationship between
vitamin D levels and the magnitude of CD4 cell recovery at three time points:
- Six months after the initiation
of treatment – association with a CD4 cell recovery of at least 50 cells/mm3.
- Twelve months after treatment
initiation – association with an increase in CD4 cell count of 100 cells/mm3
- 24 months after starting
therapy – association with a CD4 cell gain of 200 cells/mm3.
Vitamin D insufficiency was defined as ≤30 ng/dl.
Most of the women (60%) were African American and 89%
had vitamin D insufficiency prior to starting HIV therapy.
Those with vitamin D insufficiency were
more likely to aged over 38 years (94 vs 85%) and overweight or obese (98
vs 82%) than women with adequate levels of the vitamin. There was no
relationship between CD4 cell recovery and vitamin D six and twelve months
after initiating treatment.
Six months after starting HIV therapy, the
presence of an undetectable viral load was associated with increased chances of
having a CD4 cell gain of at least 50 cells/mm3 (OR = 8.89; 95% CI,
Follow-up at twelve months after the
initiation of treatment showed that an undetectable viral load was similarly
associated with a CD4 cell gain of 100 cells/mm3 or more at this
time point (OR = 7.68; 95% CI, 3.46-17.03).
However, after 24 months of therapy,
vitamin D insufficiency was found to reduce the changes of a CD4 cell gain of
200 cells/mm3 by 80% (OR = 0.20; 95% CI, 0.05-83). Once again, an
undetectable viral load was associated with robust gains in CD4 cell count (OR
= 11.38; 95% CI, 4.31-30.05).
The mean increase in CD4 cell count from
baseline to month 24 was 188 cells/mm3 for women with vitamin D
sufficiency compared to 134 cells/mm3 among those with insufficient
levels of this vitamin.
Controlling for age, race, body mass index
(BMI), HIV treatment history and undetectable viral load, the investigators
found a significant relationship between vitamin D levels and immune reconstitution
over time (p < 0.01).
“There may be biological mechanisms that
explain the effect of vitamin D insufficiency on late CD4 cell recovery after
HAART initiation,” comment the investigators. “Vitamin D insufficiency could be
related to production of naïve T cells.”
They conclude, “vitamin D insufficiency is
associated with impaired late CD4 recovery on HAART in the WIHS cohort. The
mechanism of this association…may be impaired late vitamin D-associated
production of naïve CD4 cells during immune reconstitution, however this merits