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.