Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Genetic Epidemiology Branch (TKL and PRT), Nutritional Epidemiology Branch (NDF, SMD, and CCA), and the Division of Cancer Control and Population Sciences, Epidemiology and Genomics Research Program (TKL), Rockville, MD; and the Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China (J-HF and Y-LQ).
Am J Clin Nutr. 2013 Nov;98(5):1289-97. doi: 10.3945/ajcn.113.061267. Epub 2013 Sep 11.
China has some of the highest incidence rates for gastric adenocarcinoma (GA) and esophageal squamous cell carcinoma (ESCC) in the world. Prospective studies suggested that vitamin C may reduce risks; however, associations are unclear because of limited sample size.
The objective was to examine the relation between prediagnostic plasma vitamin C and the risk of GA and ESCC.
A case-cohort study was used to assess the association between prediagnostic plasma vitamin C and incidence of GA (n = 467) and ESCC (n = 618) in the General Population Nutrition Intervention Trial. With the use of multivariate Cox proportional hazards models, we estimated the HRs and 95% CIs. We also conducted a meta-analysis of the literature up to 1 October 2012 on the relation between circulating vitamin C and gastric cancer incidence. Two cohort studies and the current study were included to assess the body of evidence.
For GA, each 20-μmol/L increase in plasma vitamin C was associated with a 14% decrease in risk (HR: 0.86; 95% CI: 0.76, 0.96). Compared with individuals with low plasma vitamin C concentrations (≤28 μmol/L), those with normal concentrations (>28 μmol/L) had a 27% reduced risk of GA (HR: 0.73; 95% CI: 0.56, 0.94). No association between vitamin C concentrations and ESCC was seen. Meta-analysis showed that the risk of incident GA among those with the highest concentration of plasma vitamin C was 31% lower (random-effects-pooled-odds ratio 0.69; 95% CI: 0.54, 0.89) than those in the lowest category.
Our data provide evidence that higher circulating vitamin C was associated with a reduced risk of incident GA, but no association was seen for ESCC.
中国是世界上胃癌（GA）和食管癌（ESCC）发病率最高的国家之一。前瞻性研究表明，维生素 C 可能降低风险；然而，由于样本量有限，关联尚不清楚。
本研究旨在探讨诊断前血浆维生素 C 与 GA 和 ESCC 风险之间的关系。
使用病例-队列研究评估了一般人群营养干预试验中诊断前血浆维生素 C 与 GA（n=467）和 ESCC（n=618）发生率之间的关系。使用多变量 Cox 比例风险模型，我们估计了 HR 和 95%CI。我们还对截至 2012 年 10 月 1 日有关循环维生素 C 与胃癌发病率之间关系的文献进行了荟萃分析。两项队列研究和本研究用于评估证据体。
对于 GA，血浆维生素 C 每增加 20μmol/L，风险降低 14%（HR：0.86；95%CI：0.76，0.96）。与低血浆维生素 C 浓度（≤28μmol/L）的个体相比，正常浓度（>28μmol/L）的个体 GA 风险降低 27%（HR：0.73；95%CI：0.56，0.94）。维生素 C 浓度与 ESCC 之间没有关联。荟萃分析显示，血浆维生素 C 浓度最高的个体发生 GA 的风险降低 31%（随机效应-合并优势比 0.69；95%CI：0.54，0.89）。
我们的数据提供了证据表明，较高的循环维生素 C 与较低的 GA 发病风险相关，但与 ESCC 无关。
