The Journal of Association of Chest Physicians

ORIGINAL ARTICLE
Year
: 2022  |  Volume : 10  |  Issue : 2  |  Page : 89--96

25-OH vitamin D3 level in tuberculosis: A cross-sectional study in a tertiary care center


Surajit Chatterjee1, Pratik Biswas2, Rituparna Bose3, Megha Agarwal4,  
1 Department of TB and Respiratory Medicine, IPGME&R and SSKM Hospital, Kolkata, West Bengal, India
2 ILS Hospitals, Howrah, West Bengal, India
3 Department of TB and Respiratory Medicine, Diamond Harbour Government Medical College and Hospital, West Bengal, India
4 Calcutta Skin Institute, Kolkata, West Bengal, India

Correspondence Address:
Rituparna Bose
Department of TB and Respiratory Medicine, Diamond Harbour Government Medical College, 210 Panch Masjid Road, Thakurpukur, Kolkata 700063, West Bengal
India

Abstract

Abstract Introduction: The immunomodulatory role of 25-hydroxycholecalciferol (25-OH vitamin D3) has been under evaluation for a long time. As tuberculosis (TB) and MDR-TB continue to be global health problems, evaluation of the role of 25-OH vitamin D3 deficiency in TB and its relation with bacillary load may help us in formulating a preventive therapy for the disease. Aims and Objectives: To assess serum 25-OH vitamin D levels in patients suffering from TB for the first time and to find the relation between serum 25-OH vitamin D levels in patients with bacillary load in respiratory samples. Results: The serum 25-OH vitamin D level was analyzed for bacillary load in the respiratory specimen in this study, which revealed that as the serum 25-OH vitamin D level decreased, the bacillary load was found to increase in the respiratory specimen.



How to cite this article:
Chatterjee S, Biswas P, Bose R, Agarwal M. 25-OH vitamin D3 level in tuberculosis: A cross-sectional study in a tertiary care center.J Assoc Chest Physicians 2022;10:89-96


How to cite this URL:
Chatterjee S, Biswas P, Bose R, Agarwal M. 25-OH vitamin D3 level in tuberculosis: A cross-sectional study in a tertiary care center. J Assoc Chest Physicians [serial online] 2022 [cited 2023 Mar 28 ];10:89-96
Available from: https://www.jacpjournal.org/text.asp?2022/10/2/89/364443


Full Text



 Introduction



The human skin produces large amounts of the secosteroid molecule 25-hydroxycholecalciferol (25-OH vitamin D) when exposed to sunlight. It functions as a hormone in the body and plays a vital role in the overall metabolism of the bony skeleton. Vitamin D deficiency (VDD) is now a globally recognized pandemic.[1] The leading cause of VDD is lack of sunlight exposure, sunscreen use, winter, latitude, malabsorption, and use of medications like glucocorticoids, rifampicin, antiretroviral therapy, etc.

Several studies have suggested possible links between vitamin D and cardiovascular disease risk,[2],[3] diabetes,[4],[5] hypertension,[6] and dyslipidemia.[7],[8] Every day, >20,000 people become infected with TB, >5000 develop TB, and >1000 die. In other words, two people die of TB every 3 minutes.[9] VDD has long been implicated in tuberculosis (TB) activation.[10] Paradoxically, prolonged treatment of TB also causes a decline in serum vitamin D levels due to antitubercular drugs like isoniazid and rifampicin.[11] Several studies have suggested that vitamin D is a potent immunomodulator of innate immune responses[12],[13] by acting as a cofactor to induce antimycobacterial activity.[14]

The emergence of MultiDrug Resistant Tuberculosis (MDR-TB) and Exrtensively Drug Resistant Tuberculosis (XDR-TB), for which existing chemotherapy is mainly ineffective, has made immunomodulator-based therapy attractive. From this perspective, the current study is undertaken to evaluate the level of 25-OH vitamin D in patients suffering from TB and to find a correlation between the level of acid-fast bacilli (AFB) in respiratory samples and the level of 25-OH vitamin D level in them.

 Aims and Objectives



To assess serum 25-OH vitamin D levels in patients suffering from TB for the first time.To find the relation between serum 25-OH vitamin D levels in patients with bacillary load in respiratory samples (AFB in sputum/induced sputum/gastric lavage/bronchoalveolar lavage (BAL)/bronchial brush/bronchial biopsy/postbronchoscopy sputum).

 Materials and Methods



Study setting: West Bengal and its neighborhood.

Timelines: 1 year (between February 2014 and February 2015).

Definition of the problem: Hypovitaminosis D is a risk factor for TB disease and is associated with antitubercular drug therapy. Since vitamin D plays an important role in augmenting cell-mediated immunity for the containment of tubercle bacilli, it is important to assess the 25-OH vitamin D level in patients suffering from TB. If found deficient or insufficient, it is necessary to correct them [Figure 1],[Figure 2],[Figure 3],[Figure 4],[Figure 5].{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}

Study population: Indoor and outdoor patients attending the Department of Pulmonary Medicine, IPGME&R and SSKM Hospital, Kolkata, India.

Sample size: In this study, 140 adult patients diagnosed with TB per selection criteria were included.

Inclusion criteria: TB patients with age >15 years, either sex.

Exclusion criteria:

Age < 15 years,Body Mass Index (BMI) < 18.5 kg/m2,history of TB or history of antitubercular drug intake and on Anti Retroviral Theraoy (ART),chronic liver disease and kidney disease,patients on corticosteroids, andhistory of vitamin D supplementation.

Method of data collection: Subjects were evaluated by a predesigned case record format. Detailed history and examination were made. History included an inquiry about adequate exposure to sunlight.

Sputum collection: Two sputum samples were collected at the designated microscopy center (DMC) per National Tuberculosis Elimination Programme (NTEP) protocol [Table 1],[Table 2],[Table 3],[Table 4],[Table 5],[Table 6],[Table 7].{Table 1}{Table 2}{Table 3}{Table 4}{Table 5}{Table 6}{Table 7}

Sputum induction: Sputum induction was done with 3% hypertonic saline after pretreatment with 200 mg of albuterol for 5 minutes.

Gastric lavage: For those unable to produce sputum after induction, gastric lavage was done with an appropriate-sized Nasogastric (NG) tube.

Bronchoscopy: Bronchoscopy was done in patients with clinical or radiological suspicion of TB who could not produce sputum or with negative sputum, induced sputum, or gastric lavage.

Estimating serum 25-OH vitamin D3: Solid-phase enzyme-linked immunoassay based on the principle of competitive binding was used to estimate serum vitamin D3.

To find out the specific objective of our study, patients were divided into five major groups based on the bacillary load in the respiratory sample:AFB load = 0: all respiratory samples negative for AFB.AFB load = 1: sputum for AFB negative but induced sputum, gastric lavage, BAL, or postbronchoscopy sputum for AFB positive.AFB load = 2: sputum for AFB 1+by fluorescent microscopy at DMC under Revised National Tuberculosis Programme (RNTCP).AFB load = 3: sputum for AFB 2+ by fluorescent microscopy at DMC under RNTCP.AFB load = 4: sputum for AFB 3+ by fluorescent microscopy at DMC under RNTCP.

Statistical analysis

Data were first entered into a Microsoft Excel spreadsheet and then analyzed by Statistica version 6 (StatSoft Inc, Tulsa, OK), MedCalc version 11.6 (MedCalc Software, Mariakerke, Belgium), and SPSS Statistics version 17 (SPSS Inc, Chicago, IL). To assess if there is a statistically significant difference in vitamin D levels in different AFB load categories, one-way Analysis of Variance (ANOVA) was followed by the Tukey test if ANOVA returns P < 0.05. Pearson and Spearman correlation coefficients were used to evaluate the correlation between various parameters.

 Results and Analyses



This study included 140 (n = 140) adult patients, 42.85% females (n = 60) and 57.14% males (n = 80), making male:female ratio as 1.33:1.

In the case of males, the average mean ± standard deviation (SD) value of serum 25-OH vitamin D level was 17.54 ± 7.964 ng/mL. The lowest value was 3.4 ng/mL, whereas the highest was 43.93 ng/mL, with a median of 16.45 ng/mL.

Among females, the average mean ± SD of serum 25-OH vitamin D level was 14.48 ± 7.846 ng/mL. The lowest value was 3.2 ng/mL, whereas the highest was 41.01 ng/mL, with a median of 13.61 ng/mL.

It was found that 66.25% (n = 53) males had deficient serum 25-OH vitamin D level, 26.25% (n = 21) had insufficient level, and rest 7.5% (n = 6) had normal level of serum 25-OH vitamin D. Among females, 80% (n = 48) of them had deficient levels, 15% (n = 9) had insufficient levels, and rest 5% (n = 3) had normal vitamin D level.

The significant deficiency was seen in the age groups 20 to 29 and 30 to 39 years, followed by 40 to 49 years and <20 years.

Only 27.85% (n = 39) of the total cases (n = 140) had adequate sunlight exposure, that is, 30 minutes of exposure of the skin over the arms and face to sunlight, and sunscreen, preferably between 10 am and 2 pm daily. In this group, the average mean ± SD of serum 25-OH vitamin D level was 18.15 ± 8.061 ng/mL. Rest, that is, 72.14% (n = 101) had inadequate exposure. The average mean ± SD of serum 25-OH vitamin D level was 15.49 ± 7.935 ng/mL.

Prevalence of VDD was 101/140, that is, 72.14% (95% confidence interval [CI]: 64.72–79.57%). The prevalence of vitamin D insufficiency was 30/140, 21.43% (95% CI: 14.63–28.23%). Prevalence of vitamin D suboptimal status was 131/140, that is, 93.57% (95% CI: 89.51–97.63: total number of deficient and insufficient cases).

Vitamin D descriptive statistics for individual AFB load groups

The cases (n = 140) were divided into five groups based on AFB load in the respiratory samples numbered AFB load 0, 1, 2, 3, and 4.

The analysis shows that as the serum 25-OH vitamin D level decreased, the bacillary load was found to increase in the respiratory specimen (either sputum/induced sputum/gastric lavage/BAL/bronchial brush/biopsy/postbronchoscopy sputum) which was significant (P < 0.001), but due to the presence of outliers (extreme values), the Spearman coefficient of rank correlation (rho) was found to be weak (−0.361).

 Discussion



Vitamin D has pleiotropic action, one of them being immunomodulation. It plays a vital role in enhancing cell-mediated immunity, ultimately leading to the containment of tubercular infection. The purpose of the present study is to evaluate the prevalence of deficiency or insufficiency of serum 25-OH vitamin D levels in patients suffering from TB, as it has been emphasized that hypovitaminosis D is a risk factor of active TB, and if not corrected in time, will fall further after commencement of therapy due to antitubercular drugs isoniazid and rifampicin.

In our study, we found that among 140 cases, 72.14% (n = 101) had VDD (i . e., <20 ng/mL), 21.43% (n = 30) had vitamin D insufficiency (i . e., 20–30 ng/mL), therefore 93.57% (95% CI: 89.51%–97.63%) of the total 140 cases had suboptimal status of vitamin D (deficiency and insufficiency).

Our study was a cross-sectional observational study, not a case–control study. A prospective study by Davies et al.[11] in the UK in 1985, comprising 50 consecutive patients presenting with TB showed that patients had lower serum concentrations of vitamin D than healthy matched controls on average. According to the Mann–Whitney U test, the difference between patients (range: 0.9–29.7, median: 6.4 ng/mL) and matched controls (range: 3.6–53.0, median: 10.9 ng/mL) was highly significant (P < 0.005).

A study by Sasidharan et al.[15] in Kerala in the year 1999 showed that the mean value of 25-OH vitamin D3 in patients with TB was 10.7 ng/mL compared to the control group, which had a mean value of 19.4 ng/mL, and the difference was statistically significant (P < 0.005).

Of the 140 cases, 42.85% were females (n = 60) and the rest, that is, 57.14% were males (n = 80), and in the case of males, the average mean ± SD value of serum 25-OH vitamin D level was 17.54 ± 7.964 ng/mL. In contrast, the average mean ± SD of serum 25-OH vitamin D level among females was 14.48 ± 7.846 ng/mL.

It was found that 66.25% (n = 53) males had deficient serum 25-OH vitamin D level, 26.25% (n = 21) had insufficient level, on the other hand among females, 80% (n = 48) of them had deficient levels and 15% (n = 9) had insufficient levels.However, a study by Ho-Pham et al.[16] on the Vietnamese population showed that the prevalence of vitamin D insufficiency was 35.4% in men with TB and 19.5% in controls (P = 0.01). In women, there were no significant differences in serum vitamin D between tubercular patients and controls. The prevalence of vitamin D insufficiency in women with TB is 45.3%, and without TB, 47.6% (P = 0.91).[16]

The serum 25-OH vitamin D level was analyzed for bacillary load in the respiratory specimen in this study, which revealed that, as the level of serum 25-OH vitamin D decreased, the bacillary load was found to increase in the respiratory specimen (either sputum/induced sputum/gastric lavage/BAL/bronchial brush/biopsy/postbronchoscopy sputum) which was significant (P < 0.001), but due to the presence of outliers (extreme values), the rho was found to be weak. The mean difference was significant between AFB load groups 0 and 4, 1 and 3, 1 and 4, and 2 and 4.

A case–control study by Wilkinson et al.[17] found that VDD was associated with active TB (odds ratio: 2.9, 95% CI: 1.3–6.5, P = 0.008), and undetectable serum vitamin D (<7 nmol/L) carried a higher risk of TB (odds ratio: 9.9, 95% CI: 1.3–76.2, P = 0.009).

The major drawback of our study was that it was a cross-sectional observational study, not a case–control study. The study was conducted only on the adult population, with the period of study limited to 1 year and the total number of cases only 140. Hence it cannot be projected to the general population.

Further studies are also required regarding longitudinal changes in the level of vitamin D in serum concerning sputum conversion and after the commencement of antitubercular drug therapy. Interventional study regarding dosing and frequency of vitamin D supplementation in patients of TB with hypovitaminosis D is also the need of the hour.

 Conclusion



To conclude, since several studies have suggested that vitamin D is a potent immunomodulator of innate immune responses by acting as a cofactor for induction of antimycobacterial activity and as there is a high prevalence of hypovitaminosis D in patients with TB, as evident in our study, it is suggested that serum 25-OH vitamin D level should be measured routinely in patients with TB and if found deficient, necessary correction should be done as vitamin D level falls further after commencement of therapy due to isoniazid and rifampicin.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patients have given their consent for their images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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