Onions and colorectal cancer.

Data about onions was provided by 4 cohorts.
No associations were found with colon (6, 9), rectal (6, 9), or total colorectal (23) cancer risk in any cohort.

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Author

Cohort name

Subjects

Years of follow-up

Cases

End point

Consumption of

Relative Risk (RR)

Adjustments

23) Lin J. (2005)

The Women's Health Study.

36,976 women aged > or = 45 years.
(USA)

223?

Colorectal cancer risk

Cooked onions, or
Raw onions

Intakes of individual vegetable items were found not appreciably to be associated with colorectal cancer risk (data not shown).

age, randomized treatment assignment, BMI, family history of colorectal cancer, history of colon polyps, physical activity, smoking status, baseline aspirin use, red meat intake, alcohol consumption, total energy intake, menopausal status, baseline post-menopausal HT use, folate intake and multivitamin use. Glycemic load in the multivariate model did not change the overall results.

9) Dorant E (1996)

The Netherlands Cohort Study.

120,852 subjects (58,279 men and 62,573 women) aged 55-69.

3.3
(1986-1989)

Colon: 150 men, and 143 women.

Proximal colon: 65 men, and 68 women.

Distal colon: 71 men, and 56 women.

Rectum: 93 men, and 57 women.

Colorectal cancer incidence
(only carcinoma)

Onions

**Men:**
Colon	Proximal colon	Distal colon	Rectum
RR = 0.87 (0.48-1.65; P = 0.47) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 1.01 (0.62-1.64). < 0.5: RR = 0.97 (0.59-1.59). ≥ 0.5: RR = 0.87 (0.48-1.65).	RR = 0.93 (0.39-2.23; P = 0.51) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 0.97 (0.49-1.93). < 0.5: RR = 0.67 (0.31-1.43). ≥ 0.5: RR = 0.93 (0.39-2.23).	RR = 1.47 (0.61-3.53; P = 0.30) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 1.29 (0.61-2.71). < 0.5: RR = 1.48 (0.71-3.09). ≥ 0.5: RR = 1.47 (0.61-3.53).	RR = 0.66 (0.28-1.52; P = 0.34) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 1.12 (0.61-2.08). < 0.5: RR = 0.99 (0.53-1.85). ≥ 0.5: RR = 0.66 (0.28-1.52).

**Women:**
Colon	Proximal colon	Distal colon	Rectum
RR = 1.49 (0.79-2.81; P = 0.32) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 1.21 (0.70-2.09). < 0.5: RR = 1.11 (0.65-1.90). ≥ 0.5: RR = 1.49 (0.79-2.81).	RR = 1.50 (0.62-3.60; P = 0.46) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 1.09 (0.50-2.36). < 0.5: RR = 1.05 (0.49-2.23). ≥ 0.5: RR = 1.50 (0.62-3.60).	RR = 1.78 (0.68-4.64; P = 0.26) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 1.21 (0.51-2.84). < 0.5: RR = 1.27 (0.56-2.91). ≥ 0.5: RR = 1.78 (0.68-4.64).	RR = 1.34 (0.55-3.31; P = 0.25) for the highest vs lowest quartile of consumption. Amount specific data (number/day): 0: RR = 1. < 0.25: RR = 0.36 (0.13-0.99). < 0.5: RR = 1.00 (0.47-2.21). ≥ 0.5: RR = 1.34 (0.55-3.31).

Age, quetelet index, alcohol intake, vitamin C and beta carotene, smoking status, education, family history of large intestinal cancer, history of cholecystectomy and chronic intestinal disease.

6 Lin J. (2006)

The Nurses's Health Study + The Health Professionals Follow Up Study.

71,976 women and 35,425 men. (USA)

10
(1990-2000)

878 of which 701 colon (408 women, 293 men), and 177 rectal (90 women, 87 men)

Colorectal cancer risk

Onions (including onion consumed as a garnish or as a vegetable)


Women:	Men:
RR = 1.13 (0.84-1.53; P = 0.81) for the highest vs lowest quintile of consumption. Amount specific data (servings): 0-0.5/wk: RR = 1. 0.6-1/wk: RR = 1.06 (0.70-1.60). 2-4/wk: RR = 1.19 (0.88-1.61). 5-6/wk: RR = 1.16 (0.86-1.56). ≥ 1/day: RR = 1.13 (0.84-1.53).	RR = 0.92 (0.65-1.29; P = 0.64) for the highest vs lowest quintile of consumption. Amount specific data (servings): 0-0.5/wk: RR = 1. 0.6-1/wk: RR = 0.79 (0.51-1.21). 2-4/wk: RR = 1.00 (0.73-1.37). 5-6/wk: RR = 1.00 (0.73-1.39). ≥ 1/day: RR = 0.92 (0.65-1.29).

Age, BMI, family history of colorectal cancer, history of colorectal polyps, prior sigmoidoscopy screening, physical activity, smoking status, red meat intake, alcohol consumption, total energy intake, total calcium intake, total folate intake, total fiber intake, aspirin use, and multivitamin use. Among women, multivariate models also included adjustment for postmenopausal hormone replacement therapy.

6) Michels KB. (2000)

The Nurses' Health Study
&
The Health Professionals' Follow-up Study.

88,764 women aged 34-59 and 47,325 men aged 40-75.
(USA)

Women: 16
(1980-1996).

Men: 10
(1986-1996)

1,181?
(937 colon cancer [368 men, 569 women], 244 rectal cancer [89 men, 155 women])

Colorectal cancer risk

onions

Intake of individual vegetables that constitute the composite items was not appreciably associated with colon or rectal cancer risk in women or men (No data shown).
Note that onion consumption was only measured in 1 (out of 4) of the female FFQs (1990), and in 1 (out of 2) of the male FFQs (1990).

age, family history of colorectal cancer, sigmoidoscopy, height, body mass index, pack-years of smoking, alcohol intake, physical activity, (women: menopausal status, postmenopausal hormone use,) aspirin use, vitamin supplement intake (ever use of multivitamins or vitamins A, C, or E), total caloric intake, and red meat consumption.

Cancer & Diet. A systematic review.

Literature review.

Relating various aspects of our diet
to colorectal cancer risk & mortality.

Onions and colorectal cancer.

Cancer & Diet. A systematic review.

Literature review.

Relating various aspects of our dietto colorectal cancer risk & mortality.

Onions and colorectal cancer.

Relating various aspects of our diet
to colorectal cancer risk & mortality.