Low serum vitamin D in North Indian multi-drug resistant pulmonary tuberculosis patients: the role of diet and sunlight

Figures & data

Table 1. Smear and culture status and disease severity in patients with MDR-TB and DS-PTB.

	MDR-TB (N = 354) n (%)	DS-PTB (N = 60) n (%)	p-value
Bacillary load^a
3^b	87 (25)	29 (48)
2^b	102 (28)	8 (13)	<0.001
1	161 (46)	18 (30)
Scanty	4 (1)	5 (8)
Culture status
Positive	354 (100)	47 (78)
Negative	0 (0)	13 (22)	<0.001
Radiographic severity^b
Unilateral	24 (7)	21 (35)
Bilateral	330 (93)	39 (65)	<0.001
Minimal	11 (3)	7 (12)
Moderately advanced	94 (27)	40 (67)	<0.001
Far advanced	249 (70)	13 (21)

^aBacillary load grading of acid-fast bacilli counts on Ziehl-Neelsen stained sputum slides as per.

WHO grading guidelines [30].

^bChest radiograph severity grading was performed by consensus of two investigators, as per the.

National Tuberculosis Association of the USA’s guidelines [31].

Table 2. Demographic details and comparison of daily nutrient intake and weekly sunlight exposure in MDR-TB and DS-PTB patients with healthy controls.

Baseline clinical characteristic of patients with MDR-TB, PTB Cat I and healthy controls
	MDR-TB (n = 354)	DS-PTB (n = 188)	Healthy controls (n = 205)	p-value
Age (yrs)	27.5 ± 10.4	27.1 ± 9.3	29.0 ± 8.9	0.10
Sex M:F	228:126	135:53	140:65	0.20
BMI (kg/m^2)	15.9 ± 2.5	17.5 ± 2.4	23.4 ± 3.0	<0.001
Energy (KJ)	1065.8 ± 238.8	1553.8 ± 489.4	1808.7 ± 481.3	<0.001
Protein (g)	32.5 ± 9.4	47.5 ± 17.9	57.8 ± 19.8	<0.001
Carbohydrate (g)	169.5 ± 41.0	258.9 ± 92.9	289.9 ± 83.1	<0.001
Fat (g)	27.9 ± 10.7	35.0 ± 14.4	45.3 ± 18.1	<0.001
Dietary fibre (g)	9.0 ± 3.2	12.5 ± 4.6	14.5 ± 4.9	<0.001
Dietary phytin (mg)	44.2 ± 32.8	57.6 ± 48.3	97.6 ± 46.1	<0.001
Dietary phosphorus (mg)	580.1 ± 187.3	934.6 ± 415.8	1008.6 ± 383.7	<0.001
Dietary calcium (mg)	294.1 ± 161.7	367.9 ± 260.8	525.7 ± 293	<0.001
Dietary vitamin D (μg)	0.1 ± 0.3	0.22 ± 0.4	1.34 ± 1.4	<0.001
Sun exposure (hrs per week)	3.7 ± 5.5	6.3 ± 7.9	3.3 ± 3.8	<0.001
BSA (%)	16.6 ± 4.9	15.8 ± 4.8	16.5 ± 4.9	0.17
SEI*	0.6 ± 1.1	1.0 ± 1.4	0.5 ± 0.6	<0.001

*Percentage of body surface area exposed to sunlight × number of hours of sun exposure per week.

MDR-TB: multidrug-resistant tuberculosis; DS-PTB: drug-susceptible pulmonary tuberculosis; M: male; F: female; BMI: body mass index; BSA: body surface area exposed; SEI: sun exposure index.

All data expressed as mean ± standard deviation except male and female sex ratio.

Figure 1. Comparison of serum vitamin D levels during seasonal variations among different study groups. Box plot showing median (line), interquartile range (boxes), and 25% to 75% percentile (whiskers): HC, healthy controls; MDR, multi-drug resistant tuberculosis, PTB Cat I, pulmonary tuberculosis Category I; Seasons (Winter-December, January, Febuary; Summer-March, April and May; Monsoon- June, July, August and September; Post Monsoon- October, November.

Figure 2. Overall comparison of serum vitamin D levels by seasons. Box plot showing median (line), interquartile range (boxes), and 25% to 75% percentile (whiskers); Seasons (Winter-December, January, Febuary; Summer-March, April and May; Monsoon- June, July, August and September; Post Monsoon- October, November) *p-value as compared to winter; #p-value as compared to Summer; @p-value monsoon vs post monsoon; Statistical method- Kruskal-Wallis Test (p < 0.05)and multiple comparision by Wilcoxon ranksum with Bonferroni correction (p < 0.08) were considered statistically significant.

Table 3. Baseline biochemical parameters of study groups.

Parameters	MDR-TB (n = 354)	DS-PTB (n = 60)	Healthy controls (n = 205)	p-value
Serum total protein (g/dL)	6.8 ± 1.1	8.0 ± 0.9	8.3 ± 0.8	<0.001
Serum albumin (g/dL)	3.5 ± 0.8	3.9 ± 0.8	4.7 ± 0.7	0.6
Serum globulin (g/dL)	3.3 ± 0.9	4.1 ± 0.8	3.7 ± 0.7	<0.001
Serum calcium (mg/dL)	5.9 ± 1.9	6.4 ± 1.1	9.0 ± 0.5	<0.001
Serum ionized calcium (mg/dL)	3.0 ± 0.9	3.2 ± 0.6	4.5 ± 0.3	<0.001
Corrected serum calcium (mg/dL)^a	6.9 ± 2.0	9.4 ± 1.6	9.5 ± 1.6	<0.001
Serum iPTH (pg/mL)	41.2 ± 31.3	29.4 ± 16.3	26.3 ± 16.9	<0.001
Serum 25(OH)D (ng/mL)^b	5.4 ± 4.0	11.6 ± 8.4	14.0 ± 10.5	<0.001

^aCorrected calcium (mg/dL) = measured total calcium (mg/dL) + 0.8 (4.4-serum albumin (g/dL)), where 4.4 represents the average albumin level.

^bSerum 25(OH) D (ng/mL) for MDR-TB= 315, DS-PTB = 50, and healthy controls = 205.

MDR-TB: multidrug-resistant tuberculosis; DS-PTB: drug-susceptible pulmonary tuberculosis.

iPTH: intact parathyroid hormone.

Data expressed as mean ± standard deviation.

Figure 3. Correlation of serum vitamin D levels with dietary vitamin D in MDR-TB, PTB Cat I and healthy controls. Scatter plot are shown between dietary vitamin D (μg/d) in X-axis and serum vitamin D levels (ng/ml)) in Y axis with correlation ccoefficient (r) and significance of correlation (p).

Table 4. Correlation of dietary vitamin D with other parameters in MDR-TB, DS-PTB and healthy controls.

	Number of participants (n)	Spearman rho correlation (r)	p-value
Serum calcium (mg/dL)	619	0.33	<0.001
Corrected serum calcium (mg/dL)^a	619	0.2	<0.001
Ionized serum calcium (mg/dL)	619	0.33	<0.001
Serum 25(OH)D (ng/mL)	570	0.3	<0.001
Serum iPTH (pg/mL)	570	−0.11	0.009
Dietary calcium (mg)	747	0.4	<0.001

^aCorrected calcium (mg/dL) = measured total calcium (mg/dL) + 0.8 (4.4- serum albumin (g/dL), where 4.4 represents the average albumin level.

747 participants: MDR-TB = 354, DS-PTB = 188 and healthy controls = 205.

619 participants: MDR-TB = 354, DS-PTB = 60, healthy controls = 205.

570 participants: MDR-TB = 315, DS-PTB = 50, and healthy controls = 205.

MDR-TB, multidrug-resistant tuberculosis; DS-PTB, drug-susceptible pulmonary tuberculosis.

iPTH: intact parathyroid hormone.

Table 5. Correlation of serum vitamin D with other parameters in all three groups.

	Number of participants (n)	Spearman rho correlation (r)	p-value
Serum calcium (mg/dL)	570	0.32	<0.001
Corrected serum calcium (mg/dL)^a	570	0.29	<0.001
Ionized serum calcium (mg/dL)	570	0.32	<0.001
Sun exposure (hours per week)	570	0.08	0.03
Body surface area exposed (%)	570	0.02	0.68
Sun exposure Index^b	570	0.08	0.02

^aCorrected calcium (mg/dL) = measured total calcium (mg/dL) + 0.8 (4.4- serum albumin (g/dL), where 4.4 represents the average albumin level.

^bPercentage of body surface area exposed to sunlight × number of hours of sun exposure per week 570 participants: MDR-TB = 315, DS-PTB = 50, and healthy controls = 205.

MDR-TB: multidrug-resistant tuberculosis; DS-PTB: drug-susceptible pulmonary tuberculosis.

Table 6. Association of study parameters with severe vitamin D deficiency in patients and healthy controls (univariate analysis).

Parameters	Healthy controls				PTB Cat I patients				MDR-TB Patients
	VDD (>10) %	Severe VDD (<10) %	Univariable OR (95%CI)	p-value*	VDD (>10) %	Severe VDD (<10) %	Univariable OR (95%CI)	p-value*	VDD (>10) %	Severe VDD (<10) %	Univariable OR (95%CI)	p-value*
Sex
Female	34	29	1		14	38	1		39	29	1
Male	66	71	1.29 (0.7-–2.3)	0.39	86	62	0.27 (0.06–1.14)	0.07	61	71	1.53 (0.79-2.96)	0.2
X-ray
Unilateral	–	–	–		33	38	1		5	8	1
Bilateral	–	–	–	–	67	62	0.81 (0.25–2.65)	0.73	95	92	0.56 (0.12–2.5)	0.45
Severity
Mild/Moderate	–	–	–		72	86	1		30	27	1
Far advanced	–	–	–	–	28	14	0.63 (0.311–1.28)	0.20	70	73	1.05 (0.74–1.49)	0.75
Cavity
No	–	–	–		10	28	1		11	13	1
Yes	–	–	–	–	90	72	0.27 (0.05–1.46)	0.13	89	87	0.86 (0.31–2.34)	0.7
Smoking
No	78	77	1		76	86	1		45	46	1
Yes	22	23	1.1 (0.57–2.13)	0.76	24	14	0.51 (0.11–2.19)	0.36	55	54	0.97 (0.51–1.84)	0.93
Alcohol
No	88	95	1		52	72	1		43	46	1
Yes	12	5	0.4 (0.14–1.23)	0.99	48	28	0.41 (0.12–1.36)	0.14	57	54	0.9 (0.47–1.71)	0.75
Resistant
RH + other drugs	–	–	–		–	–	–		41	55	1
RH	–	–	–	–	–	–	–	–	59	45	0.56 (0.29–1.08)	0.08
Serum ionized calcium
≥4.05	96	97	1		5	7	1		18	14	1
<4.05	4	3	0.8 (0.19–4.04)	0.87	95	93	0.67 (0.05–7.97)	0.75	82	86	1.4 (0.6–3.25)	0.08
Serum total calcium (mg/dL)
≥8.1	98	97	1		5	7	1		18	15	1
<8.1	2	3	1.7 (0.29–10.9)	0.5	95	93	0.67 (0.05–7.97)	0.75	82	85	1.24 (0.54–2.87)	0.6
Serum albumin (g/dL)
≥4.0	84	86	1		62	38	1		23	24	1
<4.0	16	14	0.82 (0.38–1.79)	0.6	38	62	2.65 (0.83–8.4)	0.09	77	76	0.93 (0.43–1.98)	0.85
Serum total protein (g/dL)
≥6.6	97	98	–	–	95	100	–	–	86	79	1
<6.6	3	2	–	–	5	0	–	–	14	21	1.68 (0.67–4.18)	0.26
Protein (g/day)
Male ≥60, Female ≥55	45	45	1		24	10	1		2	0
Male <60, Female <55	55	55	1.01 (0.58–1.76)	0.95	76	90	2.7 (0.56–12.9)	0.2	98	100	–	–
Energy Kcal/day)
Male ≥2320, Female ≥1900	16	20	1		10	3	1		0	0
Male <2320, Female <1900	84	80	0.76 (0.37–1.55)	0.45	90	97	2.94 (0.24–34.8)	0.3	100	100	–	–
Diet Calcium (mg/day)
≥600	34	21	1		24	0	–	–	125	3	1
<600	66	79	1.92 (1.02–3.61)	0.04	76	100	–	–	75	97	10.95 (4.11–29.1)	<0.001
Sun exposure (hours/week)
≥0.5	36	40			72	41	1		91	32	1
<0.5	64	60	0.83 (0.47–1.46)	0.51	28	59	3.54 (1.06–11.7)	0.03	9	68	21.5 (7.45–62.03)	<0.001
Body surface exposed (%)
≥18	1	2	1		14	7	1		27	2	1
<18	99	98	0.41 (0.03–4.68)	0.47	86	93	2.25 (0.34–14.83)	0.39	73	98	25.03 (7.61–82.2)	<0.001
Num of hr per week
≥3.5	40	44	1		71	31	1		84	32	1
<3.5	60	56	0.84 (0.48–1.48)	0.56	29	69	5.5 (1.62–19.02)	0.006	16	68	11.37 (4.87–26.5)	<0.001
iPTH (pg/mL)
≥21.3	49	51	1		71	14	1		30	26	1
<21.3	46	54	1.12 (0.65–1.95)	0.6	29	86	15.62 (3.78–64.5)	<0.001	70	74	1.18 (0.58–2.38)	0.64
Diet vit D (µg/day)
≥0.65	68	44	1		19	7	1		20	4	1
<0.65	32	56	2.69 (1.52–4.75)	0.001	81	93	3.17 (0.52–19.2)	0.2	80	96	6.7 (2.55–17.65)	<0.001

*p-value less than 0.05 was considered statistically significant; VDD: vitamin D deficiency; MDR-TB: multi-drug resistant tuberculosis; PTB Cat I: pulmonary tuberculosis Category I; OR: odds ratio; CI: confidence interval; R: Rifampicin; H: Isoniazid; Num of hr: number of hours; iPTH: intact parathyroid hormone; vit: vitamin.

Table 7. Association of diet calcium and sun exposure with severe vitamin D deficiency in study participants (multivariate analysis).

Parameters	Healthy controls		PTB Cat I patients		MDR-TB patients
	Multivariable OR (95%CI)	p-value*	Multivariable OR (95%CI)	p-value*	Multivariable OR (95%CI)	p-value*
Diet Calcium (mg/day)
≥600	1		–		1
<600	1.9 (1.02–3.6)	0.04			4.18 (1.21–14.4)	0.024
Body surface exposed (%)
≥18	–		–		1
<18					7.83 (2.05–29.9)	0.003
Sun exposure (hours/week)
≥0.5	–		–		1
<0.5					14.55 (4.9–43.02)	<0.001
Num of hr per week
≥3.5	–		1		–
<3.5			3.56 (0.9 4–13.37)	0.06

*p-value less than 0.05 was considered statistically significant and p-value more than 0.05 was considered statistically insignificant; MDR-TB, multi-drug resistant tuberculosis; PTB Cat I: pulmonary tuberculosis Category I; OR: odds ratio; CI: confidence interval; Num of hr: number of hours.

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Data availability statement

The data that support the findings of this study are available from the corresponding author, [Dr Jaishriram Rathored], upon reasonable request.