Association of coffee consumption with risk of colorectal cancer: a meta-analysis of prospective cohort studies

// 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 1 Department of Social Medicine and Health Management, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China 2 Bao’an Central Hospital of Shenzhen, Shenzhen, Guangdong, China 3 Department of Management, School of Economics and Management, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China 4 Department of Pathophysiology, Shenyang Medical College, Shenyang, Liaoning, China 5 National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, Changping, China 6 Division of Health System, Policy and Management, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China * These authors have contributed equally to this work Correspondence to: Zuxun Lu, e-mail: zuxunlu@yahoo.com Xiaoxv Yin, e-mail: yinxiaoxv@yahoo.com Keywords: coffee, colorectal cancer, prospective cohort, meta-analysis, epidemiology Received: October 28, 2015     Accepted: March 23, 2016     Published: April 07, 2016 ABSTRACT 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.