High prevalence of vitamin A deficiency in Crohn's disease patients according to serum retinol levels and the relative dose-response test

Table 1 Clinical characteristics of the Crohn's disease population

Parameters	n (%)	mean ± SD
Disease activity (n = 38)
In remission	34 (89.4)
Moderate activity	4 (10.52)
Severe activity	0 (0)
Disease Location (n = 35)
Ileum (L1)	12 (34.3)
Colon (L2)	8 (22.9)
Ileocolonic (L3)	15 (42.9)
Upper digestive tract (L4)	0 (0)
Phenotype (n = 31)
Non-stricturing and non-penetrating (B1)	6 (19.4)
Stricturing (B2)	9 (29.0)
Penetrating (B3)	16 (51.6)
Surgery (n = 38)
None	18 (47.4)
Small bowel resection	5 (13.1)
Colonic resection	3 (7.9)
Other procedures	12 (31.6)
Medical treatment (n = 38)
5-ASA	25 (65.8)
Immunosuppressants	28 (73.7)
Corticosteroids	3 (7.9)
Anti-TNF therapy	3 (7.9)
Antibiotics	1 (2.6)
Body composition parameters (n = 34)
LBM (kg)		42.01 ± 11.63
BMC (kg)		2.39 ± 9.73
Body fat (kg)		20.34 ± 0.51
Body fat (%)		31.59 ± 10.89

LBM: Lean body mass; BMC: Bone mineral content.

Table 2 Serum retinol levels and relative dose response test results with mean and standard deviation

Serum retinol categories1	CD Patients		Controls
	n (%)	Serum retinol values	n (%)	Serum retinol values
Normal levels (≥ 1.05 μmol/L)	27 (71)	2.69 ± 1.47	28 (85)	2.63 ± 1.29
Deficiency (< 1.05 μmol/L)	11 (29)	0.49 ± 0.26	5 (15)	0.74 ± 0.32
Mild deficiency (1.05-0.70 μmol/L)	2 (5)	1.00 ± 0.00	3 (9)	0.96 ± 0.05
Moderate deficiency (0.70-0.35 μmol/L)	5 (13)	0.46 ± 0.05	1 (3)	0.50 ± 0.00
Severe deficiency (< 0.35 μmol/L)	4 (11)	0.28 ± 0.02	1 (3)	0.3 ± 0.00
RDR test
Positive (≥ 20%)	14 (37)	0.97 ± 0.87	4 (12)	0.67 ± 0.33
Negative (< 20%)	24 (63)	2.68 ± 1.59	29 (88)	2.58 ± 1.30

¹WHO, 1996[29]. CD: Crohn's disease; RDR: Relative dose response.

Table 3 Relationship between normal and low serum retinol levels and negative and positive relative dose response test results in Crohn's disease patients and controls

Serum retinol levels	RDR test
	Negative		Positive
	CD	CT	CD	CT
Normal	22	28	5	0
Low	2	1	9	4
Total	24	29	14	4

CT: Controls; CD: Crohn's disease; RDR: Relative dose response.

Table 4 Body composition parameters, vitamin A intake, disease duration and clinical characteristics of interest in Crohn's disease patients, according to serum retinol level

Parameters	< 1.05 μmol/L(n = 11)	≥1.05 μmol/L(n = 27)	P value
BMI (kg/m2)	21.69 ± 2.74	25.65 ± 5.48	0.029
Weight (kg)	58.75 ± 9.46	68.96 + 15.59	0.051
Body fat (%)	26.13 ± 10.32	33.27 ± 11.68	0.131
LM (kg)	38.66 ± 8.35	43.04 ± 10.03	0.272
BMC (kg)	2.21 ± 0.55	2.44 ± 0.50	0.273
Body fat (kg)	13.22 ± 5.43	22.53 ± 11.28	0.032
Vitamin A intake (μg/d)	1125.7	1163.9	0.561
Disease duration (yr)	6.73 ± 7.89	2.41 ± 2.94	0.164
Bowel resection	7 (63)	13 (48)	0.386
Ileal resection	2 (18)	3 (11)	0.956
Ileal involvement	10 (90)	20 (74)	0.430
Active disease (HB index)	3 (27)	1 (4)	0.330
High CRP levels	2 (18)	9 (33)	0.430
Low HB levels	1 (9)	5 (18)	0.345

Data are represented as mean ± SD, median or n (%). BMI: Body mass index; LM: Lean body mass; BMC: Bone mineral content.