A dose-response meta-analysis reveals an association between vitamin B12 and colorectal cancer risk.

Nai-Hui Sun; Xuan-Zhang Huang; Shuai-Bo Wang; Yuan Li; Long-Yi Wang; Hong-Chi Wang; Chang-Wang Zhang; Cong Zhang; Hong-Peng Liu; Zhen-Ning Wang; Sun, Nai-Hui; Huang, Xuan-Zhang; Wang, Shuai-Bo; Li, Yuan; Wang, Long-Yi; Wang, Hong-Chi; Zhang, Chang-Wang; Zhang, Cong; Liu, Hong-Peng; Wang, Zhen-Ning

<bold>Objective: </bold>The current meta-analysis evaluated the association between vitamin B12 intake and blood vitamin B12 level and colorectal cancer (CRC) risk.<bold>Design: </bold>The PubMed and EMBASE databases were searched. A dose-response analysis was performed with generalized least squares regression, with the relative risk (RR) and 95 % CI as effect values.<bold>Setting: </bold>The meta-analysis included seventeen studies.<bold>Subjects: </bold>A total of 10 601 patients.<bold>Results: </bold>The non-linear dose-response relationship between total vitamin B12 intake and CRC risk was insignificant (P=0·690), but the relationship between dietary vitamin B12 intake and CRC risk was significant (P<0·001). Every 4·5 μg/d increment in total and dietary vitamin B12 intake was inversely associated with CRC risk (total intake: RR=0·963; 95 % CI 0·928, 0·999; dietary intake: RR=0·914; 95 % CI 0·856, 0·977). The inverse association between vitamin B12 intake and CRC risk was also significant when vitamin B12 intake was over a dosage threshold, enhancing the non-linear relationship. The non-linear dose-response relationship between blood vitamin B12 level and CRC risk was insignificant (P=0·219). There was an insignificant association between every 150 pmol/l increment in blood vitamin B12 level and CRC risk (RR=1·023; 95 % CI 0·881, 1·187).<bold>Conclusions: </bold>Our meta-analysis indicates that evidence supports the use of vitamin B12 for cancer prevention, especially among populations with high-dose vitamin B12 intake, and that the association between CRC risk and total vitamin B12 intake is stronger than between CRC risk and dietary vitamin B12 intake only.

COLON cancer risk factors; VITAMIN B in human nutrition; DOSE-response relationship in biochemistry; BLOOD testing; EVIDENCE-based medicine; COLON tumors; COMPARATIVE studies; DIET; RESEARCH methodology; MEDICAL cooperation; META-analysis; RECTUM tumors; RESEARCH; VITAMIN B12; EVALUATION research

Public Health Nutrition, 2016, Vol 19, Issue 8, p1446

1368-9800

Academic Journal

10.1017/S136898001500261X