New study suggests U-shaped curve for vitamin D and risk of mortality among infants with HIV

Posted on: January 16, 2015   by  Amber Tovey

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A recent study found that both high and low vitamin D levels are related to increased risk of mortality among both HIV-infected and HIV-exposed infants in Tanzania.

There are approximately 35 million people currently living with HIV. Although people are affected by HIV all around the world, 68% of new cases are in sub-Saharan Africa. HIV is a sexually transmitted infection, but it can also spread from mother to child during pregnancy, childbirth, or breastfeeding.

When a person is infected with HIV, their immune system becomes weaker, causing them to become more susceptible to infections and cancer. Since vitamin D plays an important role in the immune system, researchers have become interested in whether it plays a role in HIV.

Research has primarily focused on the relationship between vitamin D and HIV in adult populations, with one study suggesting a relationship between vitamin D deficiency and increased mortality.

In an effort to investigate the role of vitamin D status in HIV during infancy, researchers analyzed data from 253 HIV-infected infants and 948 HIV-exposed infants. They wanted to determine whether vitamin D status was related to morbidity and mortality among the infants.

The researchers collected data from a randomized controlled trial that evaluated the effects of multivitamins (not including vitamin D) on HIV-exposed and HIV-infected infants. During this trial, mothers and infants were followed-up through monthly clinic visits and quarterly clinical exams for two years. Vitamin D levels were measured when the infants were five to seven weeks of age.

The researchers wanted to first examine the relationship between vitamin D status and morbidity.

Here is what they found after adjusting for potential confounding factors:

  • Among HIV-exposed infants, vitamin D levels greater than or equal to 30 ng/ml were associated with a 34% increased incidence of clinical malaria (p < 0.01).
  • Among HIV-exposed infants, vitamin D levels below 10 ng/ml were associated with a 47% increased incidence of oral candidiasis, a condition in which a fungus grows along the lining of your mouth due to a suppressed immune system (p = 0.046).
  • HIV-exposed infants with vitamin D levels below 10 ng/ml were associated with a 71% increased incidence of wasting, which is the unintended progressive weight loss that is often accompanied by weakness, nutritional deficiencies, and fever (p < 0.01).

The researchers then looked to see if there was a relationship between vitamin D levels and mortality. Here is what they found after adjusting for potential confounding factors:

  • HIV-infected infants with vitamin D levels greater than or equal to 30 ng/ml were 2.47 times more likely to die than those with vitamin D levels between 20 and 29.9 ng/ml (p < 0.01).
  • HIV-exposed infants with vitamin D levels greater than or equal to 30 ng/ml were 4.00 times more likely to die than those with vitamin D levels between 20 and 29.9 ng/ml (p < 0.01)
  • HIV-infected infants with vitamin D levels below 10 ng/ml were 1.43 times more likely to die than those with vitamin D levels between 20 and 29.9 ng/ml, but this was insignificant (p = 0.29)
  • HIV-exposed infants with vitamin D levels below 10 ng/ml were 1.9 times more likely to die than those with vitamin D levels between 20 and 29.9 ng/ml, but this was insignificant. (p = 0.09)

The researchers created a graph to illustrate the relationship between vitamin D status and mortality among HIV-infected infants.

HIV U-shaped curve

The data forms a U-shaped curve, showing that both low and high vitamin D status is associated with an increased risk for mortality among HIV-infected infants.

The researchers concluded,

“In this prospective cohort study of Tanzanian infants born to HIV-infected mothers, the relation between 25(OH)D concentrations at 5–7 weeks of age and mortality appeared to be U-shaped for both HIV-infected and HIV-exposed infants.”

They went on to offer possible explanations for their surprising results,

“Infants who are exposed to the outdoors and sun during infancy may also be at high risk of exposure to mosquitos, malaria, and other pathogens that produce malaria-like symptoms.”

The researchers emphasized that these results do not prove causation, but merely display an association. Randomized controlled trials are needed to evaluate the effects of healthy vitamin D levels on morbidity and mortality among both HIV-infected and HIV-exposed infants.

Source

Sudfeld C. et al. Vitamin D Status Is Associated with Mortality, Morbidity, and Growth Failure among a Prospective Cohort of HIV-Infected and HIV-Exposed Tanzanian Infants. The Journal of nutrition, 2015.

3 Responses to New study suggests U-shaped curve for vitamin D and risk of mortality among infants with HIV

  1. hlahore@gmail.com

    Wonder how they got high levels of vitamin D
    Are, perhaps, sick infants in Tanzania kept out in the sun more?

  2. beverly@its-alimentary.com

    As the authors state, there is an association, without proof of causation. Some researchers on vitamin D say that it is inappropriate in epidemiological studies to determine D levels without also examining A levels, because many folks with high D levels got their D from cod liver oil. CLO in an amount sufficient to create high D levels could cause vitamin A toxicity. Vitamin A toxicity could in turn account for morbidity associated with high ranges of vitamin D.

  3. rcbaker200@comcast.net

    A few possibilities why this study would contradict other studies that show decreased mortality.

    1) If infants were given more (vitamin D) enriched milk in Tanzania, they would tend to have a higher incident of the harmful effects of drinking cow’s milk, which would include diarrhea, infectious disease, and in some areas of the world, unfortunately death.

    2. A key sentence in the above summary is this:

    “Here is what they found after ADJUSTING for potential confounding factors”:

    “Adjusting” is the key word. I’ve seen studies “adjust” for factors they feel are confounding, and it turns out to reverse the conclusions, Another words, LESS illness becomes MORE illness. Years later the conclusion turns out to be 100% disproved. Two examples of such adjustments: the use of DES in pregnant women for decades with tragic consequences, the denial of mainstream medicine that dietary cholesterol/fat or cholesterol levels lead to atherosclerosis from before the 1970’s until 1987 in spite of significant evidence to the contrary. Going forward it’s important to examine studies that seemingly would discourage the use of vitamin D supplements to treat vitamin D insufficiency and contradict other solid studies that don’t have those “magical” adjustments. .

    Robert Baker MD

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