Increasing CD4+ Lymphocytes in HIV Patients Treated with Antiretroviral Therapy
Vitamin D insufficiency is common in patients with HIV infection, due to chronic inflammation and treatment with antiretroviral therapy (ART). Additionally, Vitamin D insufficiency is associated with lower CD4+ lymphocyte counts.4 A study of 97 HIV-positive adults being treated with ART compared subjects who were Vitamin D sufficient to those considered insufficient (defined as 25(OH)D of ≥ 30ng/mL or <30ng/mL, respectively).4 Participants with insufficient levels received open-label Vitamin D3 50,000 IU twice weekly, for five weeks, and then 8000 IU twice weekly to complete 24 weeks. The primary endpoint was success or failure to achieve 25(OH)D of ≥ 30ng/mL at week 24.
The researchers found that Vitamin D supplementation was effective in repleting 25(OH)D levels after 24 weeks. Every 1ng/mL of 25(OH)D was associated with a 3.3cell/mm3 increase in CD4+. The researchers concluded that the study “supports a benefit of Vitamin D supplementation on immunologic recovery, which is particularly relevant to the HIV-infected population.”
Vitamin D Insufficiency Increases Susceptibility to Multiple Sclerosis
While the association between low 25(OH)D level and multiple sclerosis (MS) is well-established, it is still unclear whether this association is causal.5 To investigate this question, a Mendelian Randomization study (MR)5 was conducted, describing the effect of genetically lowered 25(OH)D on the odds of contracting MS, using data from the International Multiple Sclerosis Genetic Consortium study (including up to 14,498 cases and 24,091 healthy controls). The researchers weighted alleles according to their relative effect on 25(OH)D level and also performed sensitivity analyses. They found that each genetically determined 1-standard-deviation decrease in log-transformed 25(OH)D conferred a two-fold increase in the odds of MS.
Heart Failure Mortality and Vitamin D
Heart failure (HF) patients frequently have Vitamin D deficiency as well as hyperparathyroidism. Low 25(OH)D levels and elevated parathyroid hormone (PTH) both play an important role in cardiac remodeling and HF worsening.6 A prospective study6 of 170 HF patients found that serum levels of 1,25(OH)D decreased with increased HF severity. Most of the patients had levels of 1,25(OH)D below 30ng/mL. The 1,25(OH)D to PTH(1-84) ratio and the 1,25(OH)D2 to PTH(1-84) ratio were found to be most significantly related to HF severity. After a median follow-up of 1.4 years, 106 out of the 170 patients had suffered CV death. The researchers concluded that 1,25(OH)D and its ratios to PTH(1-84) independently predicted CV mortality in chronic HF.