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.
Dr Chao and colleagues from America undertook a study in order to examine the relationship between recent and long-term meat consumption and the risk of incident colon and rectal cancer.
The research team enrolled a cohort of 148 610 adults aged 50 to 74 years (median, 63 years), residing in 21 states with population-based cancer registries.
The participants provided information on meat consumption in 1982 and again in 1992/1993 when enrolled in the Cancer Prevention Study II (CPS II) Nutrition Cohort.
The researchers were able to identify 1667 incident colorectal cancers from follow-up from time of enrollment in 1992/1993 through to August 31, 2001.
Participants contributed person-years at risk until death or a diagnosis of colon or rectal cancer.
The research team calculated the incidence rate ratio (RR) of colon and rectal cancer.
|Persons in the highest tertile of consumption had higher risk of distal colon cancer associated with processed meat|
The researchers found that a high intake of red and processed meat reported in 1992/1993 was associated with higher risk of colon cancer.
This result was revealed after having adjusted for age and energy intake but not after further adjustment for body mass index, cigarette smoking, and other covariates.
When the researchers considered long-term consumption, persons in the highest tertile of consumption in both 1982 and 1992/1993 had higher risk of distal colon cancer associated with processed meat.
In addition, the research team found that those in the highest tertile had a higher ratio of red meat to poultry and fish relative to those persons in the lowest tertile at both time points.
The researchers found that 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, as was high consumption reported in both 1982 and 1992/1993.
Dr Chao concluded, "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."