Association between 25-OH vitamin D and insulin is independent of lipoatrophy in HIV

Association of Low Vitamin D with Complications of HIV and AIDS: A literature Review

With the advent of combination antiretroviral therapy (cART), the survival of HIV patients has improved dramatically, but the complications of the disease and treatment have become an important issue in the management of HIV patients. Vitamin-D deficiency is common in HIV patients. Low vitamin-D is associated with different comorbidities in the HIV uninfected general population. In this review, we first briefly describe vitamin D synthesis and mechanism of action and we focus on the epidemiological and clinical data dealing with the relationship between vitamin D deficiency in HIV infection with several comorbidities which has been found to be increasingly common in patients living with HIV infection. We searched the PubMed database using the keywords "HIV," "vitamin D" and other common disorders or conditions that are relatively common in HIV infection. The other conditions included in the search were osteoporosis and fracture, cardiovascular disease, diabetes and insulin resistance, active tuberculosis, hepatitis-C co-infection, and HIV disease progression. Articles presenting original data as well as systematic reviews and met analysis related to HIV population were included in our analysis. Vitamin-D deficiency seems to be associated with several adverse outcomes in HIV patients but a definite cause and effect relationship with vitamin-D is yet to be confirmed in most of the cases. However, the literature supporting the efficacy of vitamin-D supplementation is lacking.

Continued Interest and Controversy: Vitamin D in HIV

PURPOSE OF REVIEW

Vitamin D (VitD) deficiency is highly prevalent among HIV-infected individuals. Given the overlapping risk for several chronic disease and immunomodulatory outcomes from both long-standing HIV and VitD deficiency, there is great interest in clarifying the clinical role of VitD for this population.

RECENT FINDINGS

Recent studies have expanded our knowledge regarding the epidemiology and mechanisms of VitD deficiency-associated outcomes in the setting of HIV. Clinical trials focusing on VitD supplementation have demonstrated a positive impact on bone mineral density in subgroups of HIV-infected individuals initiating ART or on suppressive ART regimens; however, significant heterogeneity exists between studies and data are less consistent with other clinical outcomes. Further research is needed to clarify uncertainly in several domains, including identifying patients at greatest risk for poor outcomes from VitD deficiency, standardizing definitions and measurement techniques, and better quantifying the benefits and risks of VitD supplementation across different demographic strata for skeletal and extra-skeletal outcomes.

The Association of Gender, Age, Efavirenz Use, and Hypovitaminosis D Among HIV-Infected Adults Living in the Tropics

Vitamin D, which is important for calcium homeostasis and bone metabolism, has several noncalcemic actions. Low vitamin D levels have been observed in HIV-infected patients from high latitudes, with consequently reduced bone mineral density (BMD), but data from the tropics are scarce. We aimed to determine the prevalence of and risk factors for hypovitaminosis D among HIV-infected patients in the tropics. This was a cross-sectional study to determine serum 25-hydroxyvitamin D [25(OH)D] levels in HIV-infected patients who attended our HIV clinic in Bangkok, Thailand from July 2010 to June 2011. Hypovitaminosis D was defined as vitamin D insufficiency and deficiency [25(OH)D 20-30 ng/ml and <20 ng/ml, respectively]. Hypovitaminosis D prevalence was calculated and risk factors were determined using multivariate logistic regression. A total of 673 HIV-infected adults were included. The median age was 41 years and 47% were females. The median body mass index (BMI) was 21.9 kg/m(2) and 93% were using antiretroviral therapy (ART), with a median (IQR) duration of 8.9 (5.0-10.4) years. Thirty-one percent were using efavirenz (EFV). The prevalence of vitamin D insufficiency and deficiency was 40.6% and 29.9%, respectively. In multivariate analysis, female gender [odds ratio: OR (95% confidence interval: 95% CI) 1.7 (1.2-2.3), p = 0.005], age >37 years [OR (95% CI) 1.6 (1.1-2.4), p = 0.01], and EFV use [OR (95% CI) 2.0 (1.3-3.2), p = 0.004] were independent predictors of hypovitaminosis D. Even in tropical areas where the sun is abundant, hypovitaminosis D is highly prevalent. Thus, treatment of low vitamin D in HIV-infected patients at high risk should not be ignored to prevent reductions in BMD and other hypovitaminosis D-related comorbidities.

Vitamin D Levels and Markers of Inflammation and Metabolism in HIV-Infected Individuals on Suppressive Antiretroviral Therapy

Data on vitamin D insufficiency as a cause of inflammation and metabolic dysfunction in HIV-infected individuals are conflicting. We examined the relationships between levels of 25-hydroxyvitamin D [25(OH)D] and biomarkers of inflammation and metabolism in stored blood samples from a prospective trial of vitamin D repletion. Blood samples from HIV-infected individuals on antiretroviral therapy (ART) with HIV-1 RNA <200 copies/ml enrolled in a prospective study were analyzed for 25(OH)D levels, a broad panel of cytokines, highly sensitive C-reactive protein, D-dimer, adiponectin, leptin, and insulin. Correlations between markers and 25(OH)D levels were determined. The Wilcoxon Rank Sum test was used to compare markers between individuals 25(OH)D insufficient and sufficient at baseline and before and after repletion among those who were insufficient and repleted to ≥30 ng/ml after 12 weeks. Of 106 subjects with stored plasma [66 with 25(OH)D <30 ng/ml and 40 ≥ 30 ng/ml], the median age was 50, the CD4 count was 515 cells/mm(3), 94% were male, and the median baseline 25(OH)D was 27 ng/ml. Higher 25(OH)D levels were associated with lower tumor necrosis factor (TNF)-α (r = -0.20, p = 0.04) and higher adiponectin levels (r = 0.30, p = 0.002). Following successful repletion to 25(OH)D ≥30 ng/ml there were no significant changes in inflammatory or metabolic parameters. Our study found associations between low 25(OH)D levels and TNF-α and adiponectin. Repletion did not result in changes in markers of inflammation or metabolism. These data support continued study of the relationship between vitamin D, inflammation, and metabolism in treated HIV infection.

Vitamin D status in Well-Controlled Caucasian HIV Patients in Relation to Inflammatory and Metabolic Markers--A Cross-Sectional Cohort Study in Sweden

To study vitamin D (25OH D₃) in relation to (i) microbial translocation (ii) systemic inflammation and (iii) blood lipid markers, in Caucasian, well-controlled HIV patients and healthy controls, plasma and serum samples from n = 97 male, HIV patients on HAART with immeasurable viral load (<20 copies/ml) since median 6.5 years and no concurrent inflammatory or infectious disease and n = 30 healthy controls were analysed for (i) LPS; (ii) sCD14, hsCRP, IL-4, IL-6, IL-10, IL-17, MCP-1 and IFN-γ; as well as (iii) blood lipids. Vitamin D levels were similarly distributed and equally low in both HIV patients and controls. There was no association between vitamin D levels and markers of microbial translocation, systemic inflammation or dyslipidemia. LPS levels were similar in both groups but HIV patients expressed higher levels of sCD14 and hsCRP, with HIV as an independent risk factor. HIV patients had higher cholesterol and Apo B levels. Notably, more HIV patients smoked and smoking was associated with lower vitamin D levels. In conclusion; these well-treated Caucasian HIV patients had similar vitamin D levels as healthy controls. However, despite perfect virological control, they exhibited slightly increased inflammatory markers and disturbed blood lipids. However, neither of these parameters were associated with low vitamin D levels but appeared to be linked to the HIV-disease per se. Thus, the rationale for vitamin D substitution as a way to improve microbial translocation and systemic inflammation is not fully supported in this HIV population.

Associations between 25-hydroxyvitamin D and immunologic, metabolic, inflammatory markers in treatment-naive HIV-infected persons: the ANRS CO9 «COPANA» cohort study

Objectives

Low 25(OH)D has been associated with dyslipidemia, insulin resistance and inflammation in both general and HIV-infected (mostly treated) populations. We investigated these associations in antiretroviral-naïve HIV-infected persons.

Design

We measured plasma 25(OH)D, metabolic, immunologic and inflammatory markers in 355 persons (204 Whites, 151 Blacks) at enrollment in the ANRS COPANA cohort.

Methods

25(OH)D levels were categorized <10 ng/mL (severe deficiency) and <20 ng/mL (deficiency). Statistical analyses were adjusted for sampling season, ethnicity and the interaction between season and ethnicity.

Results

25(OH)D insufficiency (<30 ng/mL), deficiency (<20 ng/mL) and severe deficiency (<10 ng/mL) were highly prevalent (93%, 67% and 24% of patients, respectively). Blacks had significantly lower 25(OH)D than Whites (median: 13 vs. 17 ng/mL, P<0.001), with markedly less pronounced seasonal variation. Smoking and drinking alcohol were associated with having a 25 OHD level<10 ng/mL. In patients with 25(OH)D<10 ng/mL, the proportion of persons with a CD4 count<100/mm³ was higher than in patients with 25(OH)D≥10 ng/mL (18.8% vs. 10.7%, P = 0.04). Persons with 25 OHD<10 ng/mL had higher levels of hsCRP (1.60 mg/L [IQR: 0.59–5.76] vs. 1.27 mg/L [0.58–3,39], P = 0.03) and resistin (16.81 ng/L [IQR: 13.82–25.74] vs. 11.56 ng/L [IQR: 8.87–20.46], P = 0.02), and, among Blacks only, sTNFR2 (2.92 ng/mL [2.31–4.13] vs. 2.67 ng/mL, [1.90–3.23], P = 0.04). The strength and significance of the association between CD4<100/mm³ and 25 OHD<10 ng/mL were reduced after adjustment on sTNFR1, sTNFR2, and hsCRP levels. In multivariate analysis, a CD4 count <100/mm³, resistin concentration and smoking were independently associated with 25(OH)D<10 ng/mL.

Conclusions

Severe vitamin D deficiency was associated with low CD4 counts and increased markers of inflammation in ARV-naïve HIV-infected persons.

Vitamin D and HIV infection: a review of the clinical evidence

The positive effects of vitamin D in different acute and chronic diseases (e.g., bone and renal disorders, acute and chronic respiratory tract infections, and diabetes mellitus), and regulation of immune system function have been shown. In this review vitamin D status and the effects of its supplementation alone or in combination with other bone-modifying substances like calcium and bisphosphonates on the different aspects of human health have been investigated in HIV+ individuals. Three scientific electronic databases have been investigated for extracting related articles. Searching only PubMed yielded 59 results with ‘HIV OR AIDS’ and ‘Vitamin D’ keywords. Because many of the studies in this field are observational or cross-sectional, designing comprehensive and eligible randomized clinical trials has been recommended by several authors in order to develop evidence-based clinical practice guidelines to determine the best regimen of vitamin D supplementation in HIV-infected patients.

Vitamin D and insulin resistance in non-diabetic women's interagency HIV study participants

We explored the relationship between vitamin D levels and insulin resistance (IR) among 1082 nondiabetic (754 HIV-infected) women enrolled in the Women's Interagency HIV study (WIHS), a large and well-established cohort of HIV infected and uninfected women in the US. Vitamin D levels 20-29 ng/mL were considered insufficient and <20 ng/mL deficient. IR was estimated using the homeostasis model assessment (HOMA) and a clinically significant cut-off ≥2.6 was used for HOMA-IR. In the unadjusted analysis, women who were vitamin D insufficient or deficient were 1.62 (95% CI: 1.01-2.61, p=0.05) and 1.70 (95% CI: 1.11-2.60, p=0.02) times more likely to have HOMA values≥2.6 compared to women with sufficient vitamin D. The association did not remain significant after adjustment for factors associated with IR. Among the 754 HIV-infected women, current PI use (OR 1.61, 95% CI: 1.13-2.28, p=0.008) remained independently associated with HOMA ≥2.6 while vitamin D insufficiency (OR 1.80, 95% CI: 0.99-3.27, p=0.05) was marginally associated with HOMA ≥2.6 after adjustment. Ethnicity, body mass index, smoking status, and hepatitis C status were independently associated with insulin resistance in HIV-infected and uninfected women. We found a marginally significant association between vitamin D insufficiency and insulin resistance among nondiabetic HIV-infected WIHS women.

Prevalence and Factors Associated with Vitamin D Deficiency and Hyperparathyroidism in HIV-Infected Patients Treated in Barcelona

Vitamin D deficiency is an important problem in patients with chronic conditions including those with human immunodeficiency virus (HIV) infection. The aim of this cross-sectional study was to identify the prevalence and factors associated with vitamin D deficiency and hyperparathyroidism in HIV patients attended in Barcelona. Cholecalciferol (25OH vitamin D3) and PTH levels were measured. Vitamin D insufficiency was defined as 25(OH) D < 20 ng/mL and deficiency as <12 ng/mL. Hyperparathyroidism was defined as PTH levels >65 pg/mL. Cases with chronic kidney failure, liver disease, treatments or conditions potentially affecting bone metabolism were excluded. Among the 566 patients included, 56.4% were exposed to tenofovir. Vitamin D insufficiency was found in 71.2% and 39.6% of those had deficiency. PTH was measured in 228 subjects, and 86 of them (37.7%) showed high levels. Adjusted predictors of vitamin D deficiency were nonwhite race and psychiatric comorbidity, while lipoatrophy was a protective factor. Independent risk factors of hyperparathyroidism were vitamin D < 12 ng/mL (OR: 2.14, CI 95%: 1.19–3.82, P: 0.01) and tenofovir exposure (OR: 3.55, CI 95%: 1.62–7.7, P: 0.002). High prevalence of vitamin deficiency and hyperparathyroidism was found in an area with high annual solar exposure.