Case Control Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 21, 2016; 22(27): 6257-6267
Published online Jul 21, 2016. doi: 10.3748/wjg.v22.i27.6257
Effect of dietary vitamin C on gastric cancer risk in the Korean population
Bach Viet Hoang, Jeonghee Lee, Il Ju Choi, Young-Woo Kim, Keun Won Ryu, Jeongseon Kim
Bach Viet Hoang, Young-Woo Kim, Jeongseon Kim, Department of Cancer Control and Policy, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang-si, Gyeonggi-do 10408, South Korea
Jeonghee Lee, Jeongseon Kim, Molecular Epidemiology Branch, Research Institute, National Cancer Center, Goyang-si, Gyeonggi-do 10408, South Korea
Il Ju Choi, Young-Woo Kim, Keun Won Ryu, Center for Gastric Cancer, National Cancer Center Hospital, National Cancer Center, Goyang-si, Gyeonggi-do 10408, South Korea
Author contributions: Hoang BV and Lee J contributed equally to this work; Hoang BV and Lee J analyzed and interpreted the data; Hoang BV and Kim J wrote the manuscript; Choi IJ, Kim YW and Ryu KW contributed to data collection; and Kim J had primary responsibility for the final content.
Institutional review board statement: The study was reviewed and approved by the National Cancer Center Institutional Review Board.
Informed consent statement: All study participants or their legal guardian provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Data sharing statement: The technical appendix, statistical code, and dataset are available from the corresponding author at jskim@ncc.re.kr. The participants gave informed consent for data sharing. No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Jeongseon Kim, Professor, Department of Cancer Control and Policy, Graduate School of Cancer Science and Policy, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 10408, South Korea. jskim@ncc.re.kr
Telephone: +82-31-9202570 Fax: +82-31-9202579
Received: March 19, 2016
Peer-review started: March 22, 2016
First decision: May 12, 2016
Revised: June 3, 2016
Accepted: June 28, 2016
Article in press: June 29, 2016
Published online: July 21, 2016
Processing time: 118 Days and 5.1 Hours
Abstract

AIM: To investigate the effects of dietary vitamin C and foods containing vitamin C on gastric cancer risk.

METHODS: Our study included 830 control subjects and 415 patients. Data regarding demographics, medical history, and lifestyle, including dietary and nutrient intake, were collected using reliable self-administered questionnaires. Dietary intake information was collected from the participants using a food frequency questionnaire that has been previously reported as reliable and valid. A rapid urease test and a histological evaluation were used to determine the presence of Helicobacter pylori (H. pylori) infection. Twenty-three vitamin C-contributing foods were selected, representing over 80% of the cumulative vitamin C contribution.

RESULTS: In analyses adjusted for first-degree family history of gastric cancer, education level, job, household income, smoking status, and regular exercise, an inverse association between vitamin C intake and gastric cancer risk was observed for the highest (≥ 120.67 mg/d) vs the lowest (< 80.14 mg/d) intake category [OR (95%CI): 0.64 (0.46-0.88)], with a significant trend across the three intake categories (P = 0.007). No protective effect of vitamin C was detected after stratification by gender. No effect of vitamin C intake on the gastric cancer incidence was found in either men or women infected with H. pylori. Vitamin C-contributing foods, including cabbage [0.45 (0.32-0.63), 0.50 (0.34-0.75), 0.45 (0.25-0.81)], strawberries [0.56 (0.40-0.78), 0.49 (0.32-0.74), 0.52 (0.29-0.93)], and bananas [0.40 (0.29-0.57), 0.41 (0.27-0.62), 0.34 (0.19-0.63)], were protective factors against the risk of gastric cancer based on the results of the overall adjusted analyses and the results for men and women, respectively.

CONCLUSION: A protective effect of vitamin C and vitamin C-contributing foods against gastric cancer was observed. Further studies using larger sample sizes are required to replicate our results.

Keywords: Vitamin C; Vitamin C-contributing foods; Helicobacter pylori; Gastric cancer; Korean population

Core tip: An increased intake of vitamin C and vitamin C-contributing foods, including vegetables and fruits, may protect individuals against the risk of gastric cancer. However, we have no sufficient evidence to support the hypothesis that vitamin C has protective effect against gastric cancer in individuals infected with Helicobacter pylori.