http://jama.ama-assn.org/cgi/content/short/293/2/172

Meat Consumption and Risk of Colorectal Cancer
Ann Chao, PhD; Michael J. Thun, MD, MS; Cari J. Connell, MPH; Marjorie L.
McCullough, ScD; Eric J. Jacobs, PhD; W. Dana Flanders, MD, ScD; Carmen
Rodriguez, MD, MPH; Rashmi Sinha, PhD; Eugenia E. Calle, PhD


JAMA. 2005;293:172-182.

Context Consumption of red and processed meat has been associated with
colorectal cancer in many but not all epidemiological studies; few studies
have examined risk in relation to long-term meat intake or the association
of meat with rectal cancer.

Objective To examine the relationship between recent and long-term meat
consumption and the risk of incident colon and rectal cancer.

Design, Setting, and Participants A cohort of 148 610 adults aged 50 to
74 years (median, 63 years), residing in 21 states with population-based
cancer registries, who provided information on meat consumption in 1982
and again in 1992/1993 when enrolled in the Cancer Prevention Study II
(CPS II) Nutrition Cohort. Follow-up from time of enrollment in 1992/1993
through August 31, 2001, identified 1667 incident colorectal cancers.
Participants contributed person-years at risk until death or a diagnosis
of colon or rectal cancer.

Main Outcome Measure Incidence rate ratio (RR) of colon and rectal
cancer.

Results High intake of red and processed meat reported in 1992/1993 was
associated with higher risk of colon cancer after adjusting for age and
energy intake but not after further adjustment for body mass index,
cigarette smoking, and other covariates. When long-term consumption was
considered, persons in the highest tertile of consumption in both 1982 and
1992/1993 had higher risk of distal colon cancer associated with processed
meat (RR, 1.50; 95% confidence interval [CI], 1.04-2.17), and ratio of red
meat to poultry and fish (RR, 1.53; 95% CI, 1.08-2.18) relative to those
persons in the lowest tertile at both time points. Long-term consumption
of poultry and fish was inversely associated with risk of both proximal
and distal colon cancer. High consumption of red meat reported in
1992/1993 was associated with higher risk of rectal cancer (RR, 1.71; 95%
CI, 1.15-2.52; P = .007 for trend), as was high consumption reported in
both 1982 and 1992/1993 (RR, 1.43; 95% CI, 1.00-2.05).

Conclusions Our results demonstrate the potential value of examining
long-term meat consumption in assessing cancer risk and strengthen the
evidence that prolonged high consumption of red and processed meat may
increase the risk of cancer in the distal portion of the large intestine.