Serum vitamin D levels in male blood donors and human immunodeficiency virus and tuberculosis coinfected male patients: a comparative study

Abstract

Introduction Vitamin D plays a role in the immune function and itsdeficiency is associated with higher incidence of immune system disorders and faster progression of some infectious diseases. Tuberculosis is a major cause of death among people living with Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome. Evidence that vitamin D protects against tuberculosis has been supported by in vitro, epidemiological and some preliminary clinical studies. Broad objective: To compare vitamin D levels in healthy males and Human Immunodeficiency Virus and Tuberculosis co-infected males. Specific objectives: 1. To compare vitamin D levels in male blood donors and malesco-infected with Human Immunodeficiency Virus patients and Tuberculosis. 2. To determine the prevalence of vitamin D deficiency in patients co-infected with Human Immunodeficiency virus and Tuberculosis. 3. To determine the reference interval for vitamin D in blood donors. Methodology; Study Design This was a cross-sectional study, prospective descriptive study. Study Area Study area was Mbagathi District Hospital Tuberculosis clinic. Study Population and Sample Size Human immunodeficiency virus and tuberculosis co infected males and male blood donors were recruited to the study after giving their informed consent. Sample size was 240. Male blood donors were 120 and 120 male HIV/TB male patients. Specimen Analysis Vitamin D was run on the Cobas platform. xi Data Analysis Data was entered and stored using Microsoft excel 2013. Data was imported using STATA 13, coded, cleaned and analyzed. Numeric (continuous/categorical) data were summarized using measures of central tendency and dispersion; summaries were presented in tables. Histograms were plotted to show distributions. Pearson correlation tests were used to evaluate the linear relationship between variables. Pearson correlation statistic and corresponding p-values was reported. Two independent sample t-tests were used to compare the means of serum vitamin D between the two populations. The t statistics with corresponding p-values were reported. Reference interval determination was done using male blood donors. The lower and upper reference limits of vitamin D levels will be obtained by X/±1.96 SD. Ethical Consideration Ethical approval was sought from the Kenyatta National Hospital Data /University of Nairobi ethical review committee before carrying out this research. Results The distribution of serum vitamin D was significantly different (K-sample test for equality of medians: chi-sq=86.38; p-value<0.001) between blood donors and HIV/TB patients. Among blood donors, serum vitamin D level ranged from 42.6nmol/L to 106.7 nmol/L. Median 68.7 and mean was 69.6()nmol/L. For HIV/TB patients’ Vitamin D levels ranged between 33.9-89.8 median 44.0 and mean 44.3() nmol/L. Out of 121 HIV/TB co-infected patients had 69 vitamin D deficiency (57.0%) and 49/121 had insufficiency (37.2%) based on the WHO reference interval. Out of 121 patients, 75.2% (91) were on the intensive phase of treatment tuberculosis and 23.1% (28) in the continuation phase. Among the patients’ majority Vitamin D deficiency was more frequent (68.5%) among patients in the intensive tuberculosis compared to those in the continuation phase. There was a significant association between tuberculosis phase and vitamin D status of the patient (chi-sq=27.67; p<0.001). xii Based on the reference interval obtained in this study, 10/121 HIV/TB patients had deficient vitamin D. Prevalence of vitamin D deficiency among these patients was 8.3%. Achi-square test done to evaluate the association between HIV-TB co-infection and serum vitamin D status was significant (P value 0.002). Conclusion HIV/TB co-infected patients have a lower serum vitamin D levels as compared to blood donors (57% vs.5.7% as per WHO reference range). Prevalence of VDD is high among HIV/TB coinfected patients (57% as per WHO reference range). Using the reference interval determined in this study the prevalence of VDD was 8.3% in the HIV/TB co-infected patients. Serum vitamin D reference interval among blood donors was lower than WHO reference values. Co-infected patients in the intensive phase have lower Vitamin D than in those in the continuation phase (68.5% vs. 21.4%). Recommendations 1. Patients with Human immunodeficiency virus co-infected with Tuberculosis should have their serum vitamin D measured. 2. Reference intervals obtained in this study should be used in the KNH laboratory. 3. Every laboratory is encouraged to establish reference intervals for serum Vitamin D. 4. Further study to establish serum vitamin D reference interval in females is recommended