Overweight and abdominal fat are associated with normal bone mineral density in patients with ulcerative colitis

Table 1 Demographic, clinical, nutritional, and bone density characteristics of patients with ulcerative colitis

Variable	UC (n = 68)	Control (n = 66)	P value
Age (yr), median (IR)	39.0 (31.0-44.8)	36.5 (29.0-43.0)	0.484
Sex (female), n (%)	42 (61.8)	39 (59.1)	0.867
Smoking (yes), n (%)	2 (2.9)	4 (6.1)	0.437
Regular physical activity (yes), n (%)	16 (23.5)	15 (22.7)	1.000
Duration of illness (yes), median (IR)	5.0 (2.0-8.0)
Disease remission (yes), n (%)	66 (97.1)
Intestinal resection history (yes), n (%)	2 (2.9)
Extent of disease, n (%)
Proctitis	13 (19.1)
Left colitis	25 (36.8)
Extensive colitis	30 (44.1)
Use of glucocorticoids (yes), n (%)	12 (17.6)
Use ≥ 3 mo (yes), n (%)	8 (66.7)
Accumulated dose of glucocorticoids (g), median (IR)	1.7 (1.2-2.5)
Calcium supplement (yes), n (%)	3 (4.4)	0 (0)	0.245
Vit D supplement (yes), n (%)	5 (7.4)	0 (0)	0.058
Serum calcium (mmol/L), median (IR)	2.3 (2.2-2.4)	2.4 (2.3-2.4)	0.065
Serum albumin (g/dL), median (IR)	4.3 (4.1-4.5)	4.4 (4.1-4.6)	0.801
C-RP mg/dL, median (IR)	1.4 (0.6-5.2)	5.0 (1.0-6.2)	0.004
BMI (kg/m2), median (IR)	23.7 (20.6-26.5)	26.3 (22.8-29.0)	0.16
BMI classification, n (%)			0.020
Thinness	5 (7.4)	1 (1.5)
Eutrophy	40 (58.8)	26 (39.4)
Overweight	16 (23.5)	28 (42.4)
Obesity	7 (10.3)	11 (16.7)
WC (cm), median (IR)	80.5 (72.0-89.1)	84.6 (79.7-93.7)	0.156
LBM (kg), median (IR)	40.1 (34.5-49.4)	41.5 (35.3-52.2)	0.604
BF (kg), median (IR)	17.8 (11.5-22.6)	23.2 (17.8-28.4)	0.001
BF (%), median (IR)	32.9 (23.7-37.6)	34.8 (28.1-42.3)	0.168
TBF (kg), median (IR)	8.6 (6.3-12.5)	12.8 (7.8-16.5)	0.354
BMD (g/cm2), median (IR)
Femoral neck	0.99 (0.90-1.07)	1.06 (0.96-1.15)	0.120
Lumbar spine	1.16 (1.08-1.26)	1.21 (1.13-1.31)	0.120
Total body	1.17 (1.11-1.24)	1.22 (1.19-1.29	0.000

UC: Ulcerative colitis; SD: Standard deviation; IR: Interquartile range; BMI: Body mass index; WC: Waist circumference; LBM: Lean body mass; BF: Body fat; TBF: Trunk body fat; BMD: Bone density; C-RP: C-reactive protein.

Table 2 Demographic and clinical characteristics according to normal and low bone mineral density of patients with ulcerative colitis

Variable	Normal BMD (n = 40)	Low BMD (n = 28)	P value
Age (yr), median (IR)	37.5 (30.0-43.0)	40.0 (32.5-46.0)	0.193
Age group, n (%)
< 45 yr	31 (77.5)	20 (71.4)	0.57
≥ 45 yr	9 (22.5)	8 (28.6)
Sex, n (%)
Male	11 (27.5)	15 (53.6)	0.03
Female	29 (72.5)	13 (46.4)
Regular physical activity, n (%)
No	27 (67.5)	25 (89.3)	0.04
Yes	13 (32.5)	3 (10.7)
Duration of illness (yr), median (IR)	5.0 (2.0-9.0)	4.5 (1.2-6.7)	0.98
Extent of disease, n (%)
Proctitis	12 (30.0)	1 (3.6)	0.01
Left colitis	11 (27.5)	14 (50.0)
Extensive colitis	17 (42.5)	13 (46.4)
Use of glucocorticoids, n (%)
No	33 (84.6)	22 (78.6)	0.75
Yes	6 (15.4)	6 (21.4)
Use of glucocorticoids ≥ 3 mo, n (%)
No	3 (50.0)	1 (16.7)	0.54
Yes	3 (50.0)	5 (83.3)
Accumulated dose of glucocorticoids (g), median (IR)	1.8 (1.3-2.3)	1.5 (1.1-3.5)	0.55
Serum calcium (mmol/L), median (IR)	2.3 (2.3-2.4)	2.2 (2.2-2.3)	0.03
Serum albumin (g/dL), median (IR)	4.4 (4.1-4.6)	4.3 (4.0-4.5)	0.57
PCR mg/dL, median (IR)	3.1 (0.9-6.1)	1.6 (1.6-6.3)	0.56

SD: Standard deviation; IR: Interquartile range; BMD: Bone mineral density; C-RP: C-reactive protein.

Table 3 Prevalence and prevalence ratio of low bone mineral density according to demographic, clinical, and nutritional characteristics of patients with ulcerative colitis

Variable	Prevalence of low BMD, n (%)		PR (95%CI)	P value
Sex
Female	15	57.7	1.00
Male	13	31.0	1.86 (1.07 – 3.26)	0.029
Age group
< 45 yr	20	39.2	1.00
≥ 45 yr	8	47.1	1.38 (0.46 – 4.16)	0.583
Regular physical activity
Yes	3	18.8	1.00
No	25	48.1	2.56 (0.89 – 7.39)	0.081
Steroid use
No	23	38.3	1.00
Yes	5	62.5	1.63 (0.87 – 3.05)	0.126
Steroid use
< 3 mo	1	25.0	1.00
≥ 3 mo	5	62.5	2.50 (0.42 – 14.8)	0.313
BMI classification
Not overweight	23	51.1	1.00
Overweight	5	21.7	0.43 (0.19 – 0.97)	0.043
WC classification
Normal	21	52.5	1.00
Elevated	6	23.1	0.44 (0.21 – 0.94)	0.034
BF classification (%)
Normal	10	45.5	1.00
Elevated	18	39.1	0.86 (0.48 – 1.54)	0.614

PR: Prevalence ratio; CI: Confidence interval; BMI: Body mass index; WC: Waist circumference; BF: Body fat; BMD: Bone density; C-RP: C-reactive protein.