Obesity is associated with decreased risk of microscopic colitis in women

Table 1 Characteristics of the study population

	Cases, n = 110		Controls, n = 252
	n	Percent	n	Percent
Agea
mean	63.2	12.7	54.5	11.8
Raceb
White	102	96.2	186	85.7
Non-White	4	3.8	31	14.3
Sexa
Female	94	86.2	176	69.8
Male	15	13.8	76	30.2
Marital status
Married	75	70.8	146	66.7
Not married	31	29.3	73	33.3
Educationa
Less than college	36	34.0	122	55.7
College or postgrad	70	66.0	97	44.3
Cigarette smokingc
Never smoker	48	45.3	107	48.9
Former smoker	46	43.4	66	30.1
Current smoker	12	11.3	46	21.0
Irritable bowel syndromeb
Yes	14	13.6	60	28.0
No	89	86.4	154	72.0

^aP < 0.001.

^bP < 0.005.

^cP < 0.05.

Table 2 Body mass index and risk of microscopic colitis

	Cases		Controls
	n = 101		n = 238		Crude	Adjusted1
BMI	n	%	n	%	OR (95%CI)	aOR (95%CI)
Overall
< 25	50	49.5	73	30.7	Ref.	Ref.
25 < 30	29	28.7	60	25.2	0.71 (0.40-1.25)	0.70 (0.37-1.31)
≥ 30	22	21.8	105	44.1	0.31 (0.17-0.55)	0.35 (0.18-0.66)
Women
< 25	47	53.4	47	28.7	Ref.	Ref.
25 -30	24	27.3	34	20.7	0.71 (0.36-1.37)	0.67 (0.32-1.40)
≥ 30	17	19.3	83	50.6	0.20 (0.10-0.40)	0.21 (0.10-0.45)
Men
< 25	3	23.1	26	35.1	Ref.	Ref.
25 -30	5	38.5	26	35.1	1.67 (0.36-7.71)	2.22 (0.41-12.05)
≥ 30	5	38.5	22	29.7	1.97 (0.42-9.19)	2.92 (0.52-16.22)
Lost weight
< 25	34	60.7	32	44.4	Ref.	Ref.
25 -30	13	23.2	17	23.6	0.72 (0.30-1.71)	0.89 (0.35-2.22)
≥ 30	9	16.1	23	31.9	0.37 (0.15-0.91)	0.49 (0.19-1.28)
No weight loss
< 25	10	31.3	20	19.4	Ref.	Ref.
25 -30	13	40.6	30	29.1	0.87 (0.31-2.36)	0.64 (0.20-2.04)
≥ 30	9	28.1	53	51.5	0.33 (0.12-0.96)	0.33 (0.10-1.11)
IBS
< 25	9	69.2	15	25.4	Ref.	Ref.
25-30	2	15.4	15	25.4	0.22 (0.04-1.21)	0.26 (0.04-1.50)
≥ 30	2	15.4	29	49.2	0.11 (0.02-0.60)	0.13 (0.02-0.76)
No IBS
< 25	39	47.6	47	32.6	Ref.	Ref.
25 -30	26	31.7	37	25.7	0.85 (0.44-1.63)	0.78 (0.39-1.58)
≥ 30	17	20.7	60	41.7	0.34 (0.17-0.68)	0.38 (0.18-0.79)

¹Adjusted for age and education. BMI: Body mass index; IBS: Irritable bowel syndrome.

Table 3 Reproductive factors and risk of microscopic colitis in women

	Cases		Controls
	n = 94		n = 176		Crude	Model 11	Model 22
	n	%	n	%	OR (95%CI)	aOR (95%CI)	aOR (95%CI)
Age of menarche
≤ 11	18	20.5	46	30.3	Ref.	Ref.	Ref.
12	24	27.3	36	23.7	1.70 (0.80-3.61)	1.30 (0.53-3.17)	1.41 0.52-3.83)
13	23	26.1	38	25.0	1.55 (0.73-3.28)	0.76 (0.31-1.85)	0.54 (0.20-1.43)
≥ 14	23	26.1	32	21.1	1.84 (0.86-3.94)	0.90 (0.36-2.28)	0.85 (0.30-2.42)
Parity
Nulliparous	15	16.5	29	19.0	Ref.	Ref.	Ref.3
Parous	76	83.5	124	81.1	1.04 (0.88-1.24)	1.02 (0.83-1.25)	1.00 (0.81-1.23)
Number of live births
None	15	16.5	29	19.0	Ref.	Ref.	Ref.3
1	13	14.3	20	13.1	1.26 (0.49-3.20)	1.16 (0.39-3.48)	1.19 (0.40-3.60)
2	42	46.2	60	39.2	1.35 (0.65-2.83)	1.20 (0.50-2.89)	1.15 (0.47-2.81)
3 or more	21	23.1	44	28.8	0.92 (0.41-2.08)	0.78 (0.28-2.16)	0.83-0.30-2.35)
Age of first live birth (among parous women)
≤ 19	13	17.1	32	25.8	Ref.	Ref.	Ref.
20-23	12	15.8	42	33.9	0.70 (0.28-1.75)	0.24 (0.07-0.82)	0.23 (0.07-0.85)
24-29	26	34.2	27	21.8	2.37 (1.02-5.49)	0.76 (0.24-2.43)	0.78 (0.23-2.63)
30+	25	32.9	23	18.6	2.68 (1.13-6.31)	1.07 (0.32-3.58)	1.02 (0.28-3.68)
Oral contraceptives
No	27	29.7	23	15.0	Ref.	Ref.	Ref.
Yes	64	70.3	130	85.0	0.42 (0.22-0.79)	0.38 (0.17-0.84)	0.20 (0.08-0.52)

¹Model 1 Adjusted for age, education and body mass index (BMI).

²Model 2 adjusted for age, education, BMI, age first live birth, number of live births, age of menarche.

³Omitted age of first live birth from model because of collinearity.

Table 4 Menopausal factors and risk of microscopic colitis in women

	Cases		Controls
	n = 94		n = 176		Crude	Adjusted
	n	%	n	%	OR (95%CI)	OR (95%CI)1
Menopausal status
Pre-menopausal	13	14.4	40	26.1	Ref.	Ref.
Post-menopausal	77	85.6	113	73.9	2.10 (1.05-4.18)	1.20 (0.45-3.20)
Age at menopause
< 45	17	24.3	49	45.8	0.37 (0.19-0.74)	0.64 (0.28-1.46)
45-54	43	61.4	46	43.0	Ref.	Ref.
55+	10	14.3	12	11.2	0.89 (0.35-2.27)	079 (0.28-2.22)
Menopausal type
Surgical	31	40.3	70	62.0	Ref.	Ref.
Natural menopause	46	59.7	43	38.1	0.41 (0.23-0.75)	0.76 (0.37-1.54)
Menopausal hormones2
No	46	60.5	90	81.1	Ref.	Ref.
Ever	30	39.5	21	18.9	2.80 (1.44-5.41)	1.63 (0.73-3.62)
Years Postmenopausal hormones2
None	46	60.5	90	81.8	Ref.	Ref.
1-7 yr	15	19.7	11	10	2.67 (1.13-6.28)	1.65 (0.59-4.65)
9+ yr	15	19.7	9	8.2	3.26 (1.33-8.02)	1.68 (0.60-4.73)

¹Adjusted for age, education and body mass index.

²Among women after menopause.