Yong Gan 1 , Jiang Wu 2 , Shengchao Zhang 2 , Liqing Li 1 , 3 , Shiyi Cao 1 , Naomie Mkandawire 1 , Kun Ji 4 , Chulani Herath 1 , Chao Gao 5 , Hong Xu 1 , Yanfeng Zhou 1 , Xingyue Song 1 , Shanquan Chen 6 , Yawen Chen 1 , Tingting Yang 1 , Jing Li 1 , Yan Qiao 1 , Sai Hu 1 , Xiaoxv Yin 1 , Zuxun Lu 1
7 April 2016
A meta-analysis was performed to assess the association of coffee consumption with colorectal cancer and to investigate the shape of the association. Relevant prospective cohort studies were identified by a comprehensive search of the PubMed, Embase and Web of Science databases from their inception through August 2015. Either a random-effects model or fixed-effects model was used to compute the pooled risk estimates when appropriate. Linear and nonlinear dose-response meta-analyses were also performed. Nineteen prospective cohort studies involving 2,046,575 participants and 22,629 patients with colorectal cancer were included. The risk of colon cancer was decreased by 7% for every 4 cups per day of coffee (RR=0.93, 95%CI, 0.88-0.99; P=0.199). There was a threshold approximately five cups of coffee per day, and the inverse association for colorectal cancer appeared to be stronger at a higher range of intake. However, a nonlinear association of rectal cancer with coffee consumption was not observed ( P for nonlinearity = 0.214). In conclusion, coffee consumption is significantly associated with a decreased risk of colorectal cancer at ≥ 5 cups per day of coffee consumption. The findings support the recommendations of including coffee as a healthy beverage for the prevention of colorectal cancer.