Oxidative imbalance increases the risk for colonic polyp and colorectal cancer development

Table 1 Patients’ main characteristics

	Αdenocarcinoma, n = 56	Colon polyps, n = 33	Controls, n = 81
Age in yr, n (%)
50-59	1 (1.8)	8 (24.2)	9 (11.1)
60-69	20 (35.7)	12 (36.4)	44 (54.3)
70-79	28 (50.0)	11 (33.3)	16 (19.8)
80-94	7 (12.5)	2 (6.1)	12 (14.8)
Sex
Men	35 (62.5)	21 (63.6)	44 (54.3)
Women	21 (37.5)	12 (36.4)	37 (45.7)
Smoking
Yes	50 (89.3)	17 (51.5)	68 (84.0)
No	6 (10.7)	16 (48.5)	13 (16.0)
Number of cigarettes/d
< 20	4 ± 8.0	3 ± 17.6	0 ± 0.0
20	10 ± 20.0	6 ± 35.3	20 ± 29.4
> 20	36 ± 72.0	8 ± 47.1	48 ± 70.6
Smoking duration in yr (mean ± SD)	37.7 ± 10.0	33.5 ± 9.1	40.3 ± 6.2

Values are presented as n (%) or mean ± SD.

Table 2 Distribution (median 25-75 percentile) of antioxidants and oxidants compounds in the plasma by group

	Αdenocarcinoma, n = 56	Colon polyps, n = 33	Controls, n = 81
Αntioxidants
Αntioxidant capacity in μmol/L	185.0 (177.0-190.0)	190.0 (182.0-196.2)	305.0 (298.0-324.0)
Vitamin Α in μg/L	391.5 (288.3-493.8)	572.0 (480.0-609.0)	380.0 (350.0-416.0)
Vitamin C in μg/L	4.7 (3.9-6.5)	6.0 (4.7-10.0)	6.0 (4.5-9.0)
Vitamin E in mg/L	3.5 (2.4-3.9)	3.8 (3.5-4.2)	3.7 (3.2-4.0)
Vitamin D in ng/mL	9.0 (6.7-13.0)	9.0 (6.8-20.5)	24.0 (20.0-26.0)
Se in μg/L	62.0 (45.5-78.8)	78.0 (72.0-80.0)	76.0 (69.5-80.0)
Zn in μg/L	626.5 (594.5-782.5)	800.0 (711.0-840.0)	809.0 (780.5-842.5)
B12 in pg/L	211.0 (159.3-297.0)	250.0 (220.0-355.0)	289.0 (200.0-340.0)
Folic acid in ng/L	4.3 (3.3-4.6)	4.2 (3.9-4.6)	4.0 (3.8-4.4)
Οxidants
Οxidant activity in μmol/L	368.8 (330.8-409.0)	378.0 (348.5-409.1)	172.0.0 (167.5-178.5)
Μalondialdehyde in μmol/L)	1.9 (1.6-2.4)	1.2 (0.9-2.0)	1.8 (1.7-1.9)
Fe2+ in μg/dL)	64.0 (49.3-92.3)	110.0 (90.0-127.0)	68.0 (51.0-95.0)

Se: Selenium; Zn: Zinc; B12: Vitamin B12/cobalamin; Fe²⁺: Ferum.

Table 3 Percent change (and 95%CIs respectively) in the levels of serum antioxidant and oxidant substances compared to the control group

	Colon polyps	Colon adenocarcinoma
	% Change (95%CI)	% Change (95%CI)
Antioxidants
Antioxidant capacity	-40.1 (-41.6 to -38.5)	-40.7 (-41.8 to -39.5)
Vitamin Α	32.2 (20.8 to 44.7)	0.1 (-6.9 to 7.6)
Vitamin C	-3.1 (-15.8 to 11.6)	-12.7 (-21.9 to -2.4)
Vitamin E	4.2 (-5.0 to 14.2)	-12.3 (-18.4 to -5.7)
Vitamin D	-46.0 (-54.9 to -35.4)	-56.8 (-62.6 to -50.2)
Se	1.7 (-6.3 to 10.4)	-19.4 (-24.5 to -14.0)
Zn	-6.7 (-12.9 to 0.0)	-20.2 (-24.5 to -15.7)
B12	6.0 (-11.7 to 27.2)	-15.0 (-26.5 to -1.8)
Folic acid	2.1 (-6.9 to 12.0)	-8.2 (-14.7 to -1.3)
Oxidants
Oxidant activity	120.1 (111.7 to 128.9)	113.4 (106.8 to 120.2)
Malondialdehyde	-31.6 (-39.8 to -22.3)	10.1 (-0.6 to 21.9)
Fe2+	43.5 (22.2 to 68.5)	-8.9 (-19.8 to 3.5)

Results from multiple log-linear regression models controlling for age, sex, serum triglycerides, and smoking habits.

Table 4 Results from multiple logistic regression models (odds ratios and 95%CIs) for the risk of colon adenocarcinoma in comparison to the control group¹

	Odds ratio	95%CI	P value
Antioxidants
Vitamin Α, per 99.6 μg/L	1.20	0.77-1.88	0.430
Vitamin C, per 2.8 μg/L	0.71	0.44-1.15	0.168
Vitamin E, per 0.7 mg/L	0.57	0.39-0.84	0.004
Vitamin D, per 8.2 ng/mL	0.04	0.02-0.12	< 0.001
Se, per 13.6 μg/L	0.35	0.22-0.55	< 0.001
Zn, per 128.5 μg/L	0.16	0.09-0.31	< 0.001
B12, per 157.1 pg/L	0.80	0.51-1.26	0.337
Folic acid, per 38.1 ng/L	0.77	0.54-1.11	0.170
Oxidants
Malondialdehyde, per 0.5 μmol/L	2.09	1.27-3.45	0.004
Fe2+, per 33.9 μg/dL	0.73	0.47-1.13	0.154

¹Controlling for age, sex, serum triglycerides, and smoking habits. Se: Selenium; Zn: Zinc; B12: Vitamin B12/cobalamin; Fe²⁺: Ferum.

Table 5 Multiple logistic regression results (odds ratios and 95%CIs) for the risk of colon polyp development in comparison to the control group¹

	Odds ratio	95%CI	P value
Antioxidants
Vitamin Α, per 99.6 μg/L	8.84	3.76-20.74	< 0.001
Vitamin C, per 2.8 μg/L	0.99	0.58-1.70	0.982
Vitamin E, per 0.7 mg/L	1.51	0.87-2.63	0.141
Vitamin D, per 8.2 ng/mL	0.27	0.15-0.48	< 0.001
Se, per 13.6 μg/L	1.68	0.82-3.42	0.157
Zn, per 128.5 μg/L	0.39	0.16-0.94	0.036
B12, per 157.1 pg/L	1.51	0.92-2.46	0.103
Folic acid, per 38.1 ng/L	1.42	0.74-2.72	0.299
Οxidants
Malondialdehyde, per 0.5 μmol/L	0.35	0.20-0.60	< 0.001
Fe2+, per 33.9 μg/dL	2.58	1.53-4.33	< 0.001

¹Controlling for age, sex, serum triglycerides, and smoking habits. Se: Selenium; Zn: Zinc; B12: Vitamin B12/cobalamin; Fe²⁺: Ferum.