Nutritional Epidemiology Group, School of Food Science and Nutrition, University of Leeds, Leeds, UK.
Eur J Clin Nutr. 2012 May;66(5):561-8. doi: 10.1038/ejcn.2011.197. Epub 2011 Nov 30.
BACKGROUND/OBJECTIVES: Vitamin C intake has been inversely associated with breast cancer risk in case-control studies, but not in meta-analyses of cohort studies using Food Frequency Questionnaires, which can over-report fruit and vegetable intake, the main source of vitamin C. This is the first study to investigate associations between vitamin C intake and breast cancer risk using food diaries.
SUBJECTS/METHODS: Estimated dietary vitamin C intake was derived from 4-7 day food diaries pooled from five prospective studies in the UK Dietary Cohort Consortium. This nested case-control study of 707 incident breast cancer cases and 2144 matched controls examined breast cancer risk in relation to dietary vitamin C intake using conditional logistic regression adjusting for relevant covariates. Additionally, total vitamin C intake from supplements and diet was analysed in three cohorts.
No evidence of associations was observed between breast cancer risk and vitamin C intake analysed for dietary vitamin C intake (odds ratios (OR)=0.98 per 60 mg/day, 95% confidence interval (CI): 0.88-1.09, P (trend)=0.7), dietary vitamin C density (OR=0.97 per 60 mg/day, 95% CI: 0.87-1.07, P (trend)=0.5 ) or total vitamin C intake (OR=1.01 per 60 mg/day, 95% CI: 0.99-1.03, P (trend)=0.3). Additionally, there was no significant association for post-menopausal women (OR=1.02 per 60 mg/day, 95% CI: 0.99-1.05, P (trend)=0.3).
This pooled analysis of individual UK women found no evidence of significant associations between breast cancer incidence and dietary or total vitamin C intake derived uniquely from detailed diary recordings.
背景/目的：维生素 C 摄入量与病例对照研究中的乳腺癌风险呈负相关，但在使用食物频率问卷的队列研究的荟萃分析中并非如此，因为食物频率问卷可能会过高报告水果和蔬菜的摄入量，而水果和蔬菜是维生素 C 的主要来源。这是第一项使用饮食日记研究维生素 C 摄入量与乳腺癌风险之间关系的研究。
研究对象/方法：从英国饮食队列研究联盟的五项前瞻性研究中汇集的 4-7 天饮食日记中得出估计的饮食维生素 C 摄入量。这项在英国进行的 707 例乳腺癌病例和 2144 例匹配对照的巢式病例对照研究，使用条件逻辑回归，根据相关协变量进行调整，分析了维生素 C 摄入量与乳腺癌风险之间的关系。此外，还在三个队列中分析了来自补充剂和饮食的总维生素 C 摄入量。
未观察到乳腺癌风险与维生素 C 摄入量之间存在关联，分析饮食维生素 C 摄入量（每 60 毫克/天的比值比 (OR)=0.98，95%置信区间 (CI): 0.88-1.09，P (趋势)=0.7）、饮食维生素 C 密度（每 60 毫克/天的比值比 (OR)=0.97，95%置信区间 (CI): 0.87-1.07，P (趋势)=0.5）或总维生素 C 摄入量（每 60 毫克/天的比值比 (OR)=1.01，95%置信区间 (CI): 0.99-1.03，P (趋势)=0.3）。此外，对于绝经后妇女也没有明显的关联（每 60 毫克/天的比值比 (OR)=1.02，95%置信区间 (CI): 0.99-1.05，P (趋势)=0.3）。
这项对英国女性的汇总分析发现，从详细的日记记录中唯一得出的饮食或总维生素 C 摄入量与乳腺癌发病率之间没有显著关联的证据。
