Table 2.

Hazard ratios (HR) and 95% confidence intervals (CI) of colorectal, colon and rectum cancer for quintiles of total nitrate and nitrite, and nitrate and nitrite intakes from animal, plant, and preserved food sources

Quintile of exposure	Median intake (mg/day)	Colorectal Cancer		Colon Cancer		Rectum Cancer
		Cases	HRa (95% CI)	Cases	HRa (95% CI)	Cases	HRa (95% CI)
TOTAL
Nitrate
Q1	98.7	129	1.00	83	1.00	46	1.00
Q2	144.1	109	0.90 (0.69, 1.17)	70	0.90 (0.65, 1.25)	39	0.90 (0.58, 1.40)
Q3	182.4	106	0.88 (0.66, 1.16)	65	0.84 (0.59, 1.20)	41	0.95 (0.60, 1.50)
Q4	229	138	1.14 (0.85, 1.54)	87	1.13 (0.77, 1.66)	51	1.17 (0.72, 1.90)
Q5	313.2	137	1.08 (0.73, 1.59)	78	0.98 (0.59, 1.63)	59	1.26 (0.69, 2.32)
P trend			0.39		0.75		0.29
Nitrite
Q1	0.56	129	1.00	72	1.00	57	1.00
Q2	0.74	126	1.09 (0.85, 1.40)	81	1.27 (0.92, 1.76)	45	0.87 (0.58, 1.29)
Q3	0.87	123	1.10 (0.85, 1.43)	75	1.23 (0.88, 1.73)	48	0.94 (0.63, 1.42)
Q4	1.01	122	1.10 (0.84, 1.44)	80	1.34 (0.94, 1.90)	42	0.81 (0.52, 1.25)
Q5	1.23	119	1.05 (0.77, 1.42)	75	1.26 (0.85, 1.86)	44	0.80 (0.49, 1.29)
P trend			0.78		0.27		0.35
ANIMAL SOURCE
Nitrate
Q1	0.51	130	1.00	77	1.00	53	1.00
Q2	0.85	142	1.31 (1.03, 1.66)	86	1.34 (0.98, 1.82)	56	1.26 (0.86, 1.85)
Q3	1.13	113	1.12 (0.87, 1.45)	72	1.21 (0.87, 1.68)	41	1.00 (0.66, 1.52)
Q4	1.45	124	1.28 (0.99, 1.66)	79	1.38 (1.00, 1.91)	45	1.14 (0.76, 1.73)
Q5	2.06	110	1.15 (0.88, 1.50)	69	1.22 (0.87, 1.72)	41	1.05 (0.68, 1.61)
P trend			0.46		0.33		0.97
Nitrite
Q1	0.05	151	1.00	90	1.00	61	1.00
Q2	0.08	121	0.96 (0.75, 1.23)	74	0.99 (0.72, 1.35)	47	0.92 (0.63, 1.36)
Q3	0.11	121	1.06 (0.82, 1.35)	78	1.14 (0.83, 1.56)	43	0.93 (0.62, 1.39)
Q4	0.14	107	0.97 (0.75, 1.26)	72	1.09 (0.79, 1.51)	35	0.79 (0.51, 1.23)
Q5	0.19	119	1.17 (0.90, 1.51)	69	1.14 (0.81, 1.59)	50	1.21 (0.81, 1.82)
P trend			0.27		0.38		0.49
PLANT SOURCE
Nitrate
Q1	97.6	128	1.00	83	1.00	45	1.00
Q2	142.8	110	0.92 (0.70, 1.19)	70	0.90 (0.65, 1.26)	40	0.94 (0.61, 1.46)
Q3	181.1	106	0.88 (0.67, 1.17)	64	0.83 (0.58, 1.19)	42	0.99 (0.63, 1.56)
Q4	227.8	137	1.15 (0.85, 1.55)	87	1.15 (0.78, 1.68)	50	1.17 (0.72, 1.90)
Q5	311.9	138	1.10 (0.75, 1.63)	79	1.01 (0.61, 1.68)	59	1.28 (0.70, 2.36)
P trend			0.35		0.66		0.31
Nitrite
Q1	0.47	120	1.00	65	1.00	55	1.00
Q2	0.63	130	1.17 (0.91, 1.50)	82	1.38 (0.99, 1.93)	48	0.91 (0.62, 1.35)
Q3	0.75	133	1.22 (0.94, 1.58)	82	1.43 (1.02, 2.02)	51	0.97 (0.65, 1.45)
Q4	0.89	117	1.06 (0.80, 1.40)	76	1.34 (0.93, 1.91)	41	0.75 (0.48, 1.16)
Q5	1.11	119	1.03 (0.76, 1.39)	78	1.36 (0.92, 2.01)	41	0.67 (0.41, 1.09)
P trend			0.88		0.23		0.08
Preserved Foods
Nitrate
Q1	0.14	110	1.00	59	1.00	51	1.00
Q2	0.62	117	1.16 (0.90, 1.51)	72	1.35 (0.96, 1.91)	45	0.94 (0.63, 1.41)
Q3	1.65	124	1.20 (0.93, 1.55)	79	1.42 (1.01, 1.99)	45	0.95 (0.64, 1.42)
Q4	2.99	137	1.31 (1.02, 1.69)	92	1.64 (1.18, 2.28)	45	0.93 (0.62, 1.39)
Q5	8.24	131	1.13 (0.87, 1.45)	81	1.28 (0.92, 1.80)	50	0.95 (0.64, 1.40)
P trend			0.75		0.61		0.87
Nitrite
Q1	0.01	113	1.00	60	1.00	53	1.00
Q2	0.02	126	1.25 (0.97, 1.62)	78	1.48 (1.06, 2.08)	48	1.00 (0.67, 1.48)
Q3	0.06	123	1.22 (0.94, 1.57)	76	1.42 (1.01, 1.99)	47	0.99 (0.67, 1.47)
Q4	0.11	124	1.21 (0.94, 1.56)	85	1.56 (1.12, 2.18)	39	0.81 (0.53, 1.22)
Q5	0.29	133	1.16 (0.90, 1.49)	84	1.36 (0.98, 1.90)	49	0.92 (0.62, 1.36)
P trend			0.78		0.44		0.59

^aAdjusted for age, energy intake, education, physical activity, dietary vitamin C intake, carotene and folate