Peanut consumption and reduced risk of colorectal cancer in women: A prospective study in Taiwan

Table 1 Incidence and relative risk of colorectal cancer by social demographic characteristics in a Taiwan community-based cancer screening cohort (1991-2001)

Characteristic	Subject number	Personyr	Colorectal cancer
			Case number	Rate1	RR2 (95% CI3)	P
Age (yr)
< 50	12 902	129 055	18	13.9	1.00
50-59	6 679	66 812	51	76.3	5.47(3.20-9.36)	< 0.01
+     60	2 534	24 944	38	152.0	11.0 (6.30-19.4)	< 0.01
Gender
Women	11 192	112 007	39	34.8	1.00
Men	10 923	108 805	68	62.5	1.81 (1.22-2.68)	< 0.01
Education (yr)
None	4 576	45 806	30	65.5	1.00
≤ 6	9 126	91 009	56	61.5	0.94(0.61-1.47)	0.79
> 6	8 383	83 698	21	25.1	0.39(0.22-0.67)	< 0.01
Unknown	30	300	0	—	—
Ethnic group
Fukien	14 938	149 709	73	48.8	1.01(0.67-1.52)	0.96
Others4	7 128	70 612	34	48.2	1.00
Unknown	49	491	0	—	—
Residential area
Potzu	3 362	33 680	23	68.3	1.51(0.95-2.39)	0.08
Other5	18 753	187 132	84	44.9	1.00
Married
Yes	20 354	203 204	99	48.7	1.00
No	1 671	16 699	8	47.9	0.98(0.48-2.02)	0.97
Unknown	90	909	0	—	—
All	22 115	22 0812	107	48.5

¹Rate in 10⁵ persons/year;

²Relative risk;

³95% Confidence interval;

⁴Including mainland Chinese, Hskka and aborigines;

⁵Including Sanchi, Chutung, Kaoshu, Makung, Hushi and Paihsa.

Table 2 Incidence of colorectal cancer and relative risk by lifestyle factor in a Taiwan community-based cancer screening cohort among men (1991-2001)

Characteristic	Cases number	Rate1	RR2	95% CI3	P
BMI (kg/m2)
< 24.2	33	54.7	1.00
24.2-26.4	16	62.5	1.15	0.63-2.08	0.65
26.4-28.6	11	73.5	1.35	0.68-2.67	0.39
28.6 +	8	101.4	1.87	0.86-4.04	0.11
P for trend			0.11
Cholesterol (tertile4)
1	15	41.5	1.00
2	18	49.5	1.19	0.60-2.36	0.62
3	35	96.5	2.32	1.27-4.25	< 0.01
P for trend			0.004
Triglyceride (tertile5)
1	20	54.2	1.0
2	21	58.4	1.07	0.58-1.98	0.83
3	27	75.1	1.38	0.78-2.46	0.27
P for trend			0.26
Cigarette smoking (pack-yr)
0	22	45.2	1.00
1-25	21	56.7	1.26	0.69-2.28	0.46
26 +	24	105.0	2.32	1.30-4.13	< 0.01
Unknown	1	896.0	─
P for trend			0.006
Alcohol drinking
No	52	59.9	1.00
Yes	16	73.8	1.23	0.71-2.16	0.46

¹Incidence rate per 10⁵ persons/year;

²Relative risk;

³95% Confidence interval;

⁴The tertile of cholesterol level (mg/dL) was < 163, 163-197, 197+;

⁵The tertile of triglyceride level (mg/dL) was < 87, 87-145, 145 +.

Table 3 Incidence of colorectal cancer and relative risk by lifestyle factor in a Taiwan community-based cancer screening cohort among women (1991-2001)

Characteristic	Cases number	Rate1	RR2	95% CI3	P
BMI (kg/m2)
< 24.2	12	19.3	1.00
24.2-26.4	12	50.3	2.61	1.17-5.80	0.02
26.4-28.6	10	70.2	3.64	1.57-8.43	< 0.01
28.6 +	5	42.4	2.19	0.77-6.23	0.14
P for trend			0.012
Cholesterol (tertile4)
1	8	21.6	1.00
2	10	26.4	1.22	0.48-3.10	0.67
3	21	56.8	2.64	1.17-5.95	0.02
P for trend			0.012
Triglyceride (tertile5)
1	8	21.4	1.00
2	13	34.2	1.60	0.66-3.86	0.30
3	18	49.2	2.30	1.00-5.28	0.05
P for trend			0.046
Oral contraceptives
Never use	27	38.2	1.00
Ever use	7	21.7	0.57	0.25-1.31	0.19
Unknown	5	54.9
Intrauterine devices
Never use	15	35.8	1.00
Ever use	19	31.2	0.87	0.44-1.72	0.69
Unknown	5	54.5
Menopause
No	10	14.9	1.00
Yes	24	67.6	4.53	2.17-9.47	< 0.01
Unknown	5	53.5

¹Incidence rate per 10⁵ persons/year;

²Relative risk;

³95% Confidence interval;

⁴The tertile of cholesterol level (mg/dL) was < 165, 165-199, 199 +;

⁵The tertile of triglyceride level (mg/dL) was < 75, 75-126, 126 +.

Table 4 Incidence of colorectal cancer and relative risk associated with dietary factors in a Taiwan community-based cancer screening cohort (1991-2001)

Food variable	Men			Women
(meals/wk)	Cases (Rate1)	RR2 (95% CI3)	P	Cases (Rate1)	RR2 (95%CI3)	P
Folk Vegetarian
No	68 (63.9)	1.00		37 (34.1)	1.00
Yes	0			2 (67.4)	1.98(0.48-8.22)	0.35
Unknown	0	―		0	―
Sweet potato
0-1	8 (31.7)	1.00		8 (26.0)	1.00
2 +	60 (72.3)	2.26(1.08-4.73)	0.03	31 (38.4)	1.48(0.68-3.22)	0.32
Unknown	0	―		0	―
Bean products
0-1	24 (60.0)	1.00		13 (27.1)	1.00
2 +	43 (63.0)	1.04(0.63-1.71)	0.88	26 (41.0)	1.51(0.78-2.94)	0.23
Unknown	1	―		0	―
Peanut products
0-1	23 (70.8)	1.00		17 (40.4)	1.00
2 +	44 (58.1)	0.83(0.50-1.37)	0.45	21 (30.4)	0.75(0.40-1.43)	0.38
Unknown	1	―		1	―
Pickled foodstuffs
0-1	26 (68.9)	1.00		10 (21.2)	1.00
2 +	41 (58.2)	0.84(0.51-1.37)	0.48	29 (45.2)	2.13(1.04-4.37)	0.04
Unknown	1	―		0	―
Nitrated foodstuffs
0-1	59 (61.5)	1.00		34 (33.4)	1.00
2 +	6 (53.5)	0.87(0.38-2.01)	0.74	4 (44.1)	1.32(0.47-3.71)	0.60
Unknown	3	―		1	―
Smoked foodstuffs
0-1	60 (60.5)	1.00		36 (34.1)	1.00
2 +	5(65.1)	1.08(0.43-2.69)	0.87	2(38.2)	1.12(0.27-4.64)	0.88
Unknown	3	―		1	―

¹Incidence rate per 10⁵ persons/year; ²Relative risk;

³95% Confidence interval.

Table 5 Relative risk from multivariate analysis by Cox’s proportional hazard model of the community-based cancer screening cohort (1991-2001)

	Men			Women
Variables	RR1	95% CI2	P	RR1	95% CI2	P
Age (yr)	1.13	1.09-1.17	< 0.01	1.12	1.08-1.17	<0.01
Residential area
Potzu	2.13	1.24-3.68	< 0.01	NI4
Other3	1.00
Cigarette smoking (pack-yr)
0	1.00			NI4
1-25	1.77	0.97-3.26	0.06
26 +	1.51	0.83-2.74	0.18
Peanut products
0-1	1.00			1.00
2 +	0.73	0.44-1.21	0.22	0.42	0.21-0.84	0.01
Picked foodstuffs
0-1	NI 4			1.00
2 +				2.15	0.99-4.65	0.05
BMI (kg/m2)
< 24.2	1.00			NI4
24.2-26.4	1.19	0.65-2.17	0.58
26.4-28.6	1.26	0.62-2.57	0.53
28.6	1.98	0.91-4.30	0.09

¹Relative risk;

²95% Confidence interval;

³Including Sanchi, Chutung, Kaoshu, Makung, Hushi and Paihsa;

⁴Not included in the model.