Meta-Analysis
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Dec 28, 2012; 18(48): 7362-7370
Published online Dec 28, 2012. doi: 10.3748/wjg.v18.i48.7362
A meta-analysis of the effects of energy intake on risk of digestive cancers
Xiao-Feng Yu, Yi-Qian Wang, Jian Zou, Jie Dong
Xiao-Feng Yu, Yi-Qian Wang, Jian Zou, Jie Dong, Department of Gastroenterology, Huadong Hospital, Fudan University, Shanghai 200040, China
Author contributions: Yu XF and Zou J conceived the study; Data were acquired independently by Yu XF, Wang YQ and Dong J; Dong J and Zou J performed data analysis and interpretation; Zou J prepared the manuscript with contributions from all authors; all authors have read and approved the final manuscript.
Correspondence to: Dr. Jian Zou, Department of Gastroenterology, Huadong Hospital, Fudan University, 221 Yanan Xi Road, Shanghai 200040, China. apollozou@hotmail.com
Telephone: +86-21-62483180 Fax: +86-21-32140503
Received: September 14, 2012
Revised: October 4, 2012
Accepted: November 11, 2012
Published online: December 28, 2012
Processing time: 138 Days and 20.9 Hours
Abstract

AIM: To quantitatively assess the relationship between energy intake and the incidence of digestive cancers in a meta-analysis of cohort studies.

METHODS: We searched MEDLINE, EMBASE, Science Citation Index Expanded, and the bibliographies of retrieved articles. Studies were included if they reported relative risks (RRs) and corresponding 95% CIs of digestive cancers with respect to total energy intake. When RRs were not available in the published article, they were computed from the exposure distributions. Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator. We performed fixed-effects meta-analyses and meta-regressions to compute the summary RR for highest versus lowest category of energy intake and for per unit energy intake and digestive cancer incidence by giving each study-specific RR a weight that was proportional to its precision.

RESULTS: Nineteen studies consisting of 13 independent cohorts met the inclusion criteria. The studies included 995 577 participants and 5620 incident cases of digestive cancer with an average follow-up of 11.1 years. A significant inverse association was observed between energy intake and the incidence of digestive cancers. The RR of digestive cancers for the highest compared to the lowest caloric intake category was 0.90 (95% CI 0.81-0.98, P < 0.05). The RR for an increment of 239 kcal/d energy intake was 0.97 (95% CI 0.95-0.99, P < 0.05) in the fixed model. In subgroup analyses, we noted that energy intake was associated with a reduced risk of colorectal cancer (RR 0.90, 95% CI 0.81-0.99, P < 0.05) and an increased risk of gastric cancer (RR 1.19, 95% CI 1.08-1.31, P < 0.01). There appeared to be no association with esophageal (RR 0.96, 95% CI 0.86-1.07, P > 0.05) or pancreatic (RR 0.79, 95% CI 0.49-1.09, P > 0.05) cancer. Associations were also similar in studies from North America and Europe. The RR was 1.02 (95% CI 0.79-1.25, P > 0.05) when considering the six studies conducted in North America and 0.87 (95% CI 0.77-0.98, P < 0.05) for the five studies from Europe.

CONCLUSION: Our findings suggest that high energy intake may reduce the total digestive cancer incidence and has a preventive effect on colorectal cancer.

Keywords: Diet; Cancer prevention; Energy intake; Digestive cancer