Is dietary fat associated with the risk of colorectal cancer? A meta-analysis of 13 prospective cohort studies.
BACKGROUND
The results of animal studies suggest there is a significant role for dietary fat in the development of colorectal cancer (CRC). However, inconsistent results have been reported by epidemiological studies.


OBJECTIVE
To evaluate the association between total dietary fat and risk of colorectal cancer development using a meta-analysis based on prospective cohort studies.


METHODS
Published literature was retrieved from Medline, Embase and CNKI (China Knowledge Resource Integrated Database) databases updated to 1st May, 2009. Overall, thirteen prospective cohort studies with 3,635 cases and 459,910 participants were included.


RESULTS
The combined relative risk (RR) [95% confidence interval (95%CI)] for the risk of CRC was 0.99 (0.89,1.09) when the highest level of total dietary fat was versus (vs.) the lowest level. Stratified analyses according to gender, ethnicity, country and age showed that the highest level of total dietary fat did not increase the risk of CRC [RR (95%CI): 0.89 (0.77,1.03) for males; 1.09 (0.94,1.26) for females; 1.08 (0.94,1.25) for Caucasians; 0.90 (0.77,1.04) for Asians; 1.13 (0.94,1.36) for Americans; 0.92 (0.81,1.04) for individuals older than 40]. Besides those, the highest level of total fat diet also did not increase the risk of neither colon cancer [RR (95%CI): 0.96 (0.82,1.13)] nor rectal cancer [RR (95%CI):1.07 (0.63,1.82)]. Furthermore, neither animal fat nor plant fat were associated with the risk of CRC [RR (95%CI): 1.05 (0.91-1.22) for animal fat and 0.96 (0.82-1.11) for plant fat].


CONCLUSIONS
This meta-analysis suggests that dietary fat may not be associated with the increased risk of CRC. More well-designed studies with larger population performed among Asians are needed to further evaluate the associations. In addition, probable bias caused by measurement error should be noticed in this meta-analysis, and measurement error needs to be adjusted in the future studies.
Liu
Liu
L
Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Nan Chang University, 330006, Nanchang City, Jiangxi Province, China. wkjyliu@gmail.com
Zhuang
Wen
W
Wang
Ruo-Qi
RQ
Mukherjee
Rajarshi
R
Xiao
Shuo-Meng
SM
Chen
Zhong
Z
Wu
Xiao-Ting
XT
Zhou
Yong
Y
Zhang
Hai-Yan
HY
D000328:Adult; D044466:Asian People; D002681:China; D003110:Colonic Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D004041:Dietary Fats / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D044465:White People
D004041:Dietary Fats