Sessile serrated adenomas in the proximal colon are likely to be flat, large and occur in smokers

Table 1 Comparison of patient characteristics among proximal and distal sessile serrated adenoma group n (%)

	Proximal SSA (n = 47)	Distal SSA (n = 73)	Univariate OR (95%CI)	P value	Multivariate OR (95%CI)
Race (CC)	37 (78.7)	54 (74.0)	1.30 (0.54-3.12)	0.66	-
Gender (male)	21 (44.7)	27 (37.0)	1.38 (0.65-2.90)	0.45	-
Age (yr) (≥ median)	28 (59.6)	40 (54.8)	1.22 (0.58-2.56)	0.71	-
Obesity	22 (46.8)	36 (49.3)	0.90 (0.43-1.88)	0.85	-
Family history	11 (23.4)	5 (6.8)	4.16 (1.34-12.89)	0.01	4.72 (1.43-15.55)
					P = 0.01
Diabetes mellitus	14 (29.8)	23 (31.5)	0.92 (0.42-2.05)	1.00	-
Smoking	30 (63.8)	30 (41.0)	2.53 (1.19-5.39)	0.02	2.63 (1.17-5.90)
					P = 0.02
Triglyceride (mean ± SD, mg/dL)	124.9 ± 63.9	129.7 ± 67.9	-4.80 (-29.38-19.78)	0.69	-
Cholesterol (mean ± SD, mg/dL)	179.1 ± 45.8	180.9 ± 43.8	-1.80 (-18.31-14.71)	0.83	-

SSA: Sessile serrated adenoma.

Table 2 Comparison of adenoma characteristics in the proximal and distal sessile serrated adenoma n (%)

	Proximal SSA (n = 47)	Distal SSA (n = 73)	Univariate OR (95%CI)	P value
Flat SSA	47 (100.0)	57 (78.0)	-	0.0001
≥ 6 mm SSA	31 (66.0)	29 (39.7)	2.94 (1.37-6.31)	0.0080
≥ 1 cm SSA	21 (44.7)	11 (15.0)	4.55 (1.92-10.77)	0.0005

SSA: Sessile serrated adenoma.

Table 3 Comparison of patient and adenoma characteristics among proximal sessile serrated adenoma and proximal tubular adenoma groups n (%)

	Proximal SSA (n = 47)	Proximal TA (n = 78)	Univariate OR (95%CI)	P value
Family history	11 (23.4)	14 (18.0)	1.40 (0.57-3.40)	0.4900
Smoking	30 (63.8)	26 (33.3)	3.53 (1.65-7.54)	0.0010
Adenoma size ≥ 1 cm	21 (44.7)	11 (14.1)	4.92 (2.08-11.61)	0.0002
Flat morphology	47 (100.0)	46 (59.0)	-	< 0.00001

SSA: Sessile serrated adenoma; TA: Tubular adenoma.