VanEenwyk J, Davis F G, Colman N
Department of Epidemiology and Biostatistics, School of Public Health, University of Illinois, Chicago 60612.
Cancer Epidemiol Biomarkers Prev. 1992 Jan-Feb;1(2):119-24.
A case-control study was designed to assess the relationship between cervical intraepithelial neoplasia (CIN) and folate in serum, red blood cells, and diet. The association between CIN and dietary vitamin C was also investigated. Cases were selected from women with biopsy-confirmed CIN. Controls were age-, race-, and clinic-matched women with normal cervical (Pap) smears. Study participants completed self-administered food frequency (n = 100 matched pairs) and health (n = 102 matched pairs) questionnaires. Fasting venous blood samples were collected for serum (n = 98 matched pairs) and red cell (n = 68 matched pairs) folate assays. Conditional logistic regression models were used to estimate crude odds ratios and odds ratios adjusted for smoking, income, number of sexual partners, frequency of cervical smear, use of spermicidal contraceptive agents, history of genital warts, and Quetelet index. Dietary intake variables were adjusted for total energy intake prior to logistic regression. A protective effect of red cell folate was evident with adjusted odds ratios (95% confidence intervals) of 0.1 (0.0-0.4), 0.6 (0.2-2.0), and 0.5 (0.2-1.9) for those in quartiles 4 (highest), 3, and 2 compared to quartile 1 (lowest). Supporting evidence for the protective effect of folate was provided by inverse associations between CIN and folate in both serum and diet. An inverse association was also found between CIN and dietary vitamin C with adjusted odds ratios (95% confidence intervals) of 0.2 (0.0-0.7), 0.6 (0.2-1.6), and 0.6 (0.2-1.8) for those in quartiles 4, 3, and 2, respectively, compared to quartile 1. These findings support dietary recommendations, such as those of the American Cancer Society, the National Cancer Institute, and the U.S. Dietary Guidelines, which allow for adequate intake of folate and vitamin C, both of which are found in good quantity in fruits and vegetables. Increased consumption of legumes and whole grains is also in accord with current dietary recommendations, and both of these types of foods are good sources of folates.
一项病例对照研究旨在评估宫颈上皮内瘤变（CIN）与血清、红细胞及饮食中的叶酸之间的关系。同时也研究了CIN与饮食中维生素C之间的关联。病例选自活检确诊为CIN的女性。对照为年龄、种族和诊所匹配的宫颈（巴氏）涂片正常的女性。研究参与者完成了自我填写的食物频率问卷（n = 100对匹配）和健康问卷（n = 102对匹配）。采集空腹静脉血样用于血清（n = 98对匹配）和红细胞（n = 68对匹配）叶酸检测。使用条件逻辑回归模型来估计粗比值比以及针对吸烟、收入、性伴侣数量、宫颈涂片频率、使用杀精避孕剂、尖锐湿疣病史和体重指数进行调整后的比值比。在进行逻辑回归之前，对饮食摄入变量进行了总能量摄入的调整。与四分位数1（最低）相比，四分位数4（最高）、3和2的红细胞叶酸具有明显的保护作用，调整后的比值比（95%置信区间）分别为0.1（0.0 - 0.4）、0.6（0.2 - 2.0）和0.5（0.2 - 1.9）。血清和饮食中CIN与叶酸之间的负相关为叶酸的保护作用提供了支持性证据。CIN与饮食中维生素C之间也发现了负相关，与四分位数1相比，四分位数4、3和2的调整后比值比（95%置信区间）分别为0.2（0.0 - 0.7）、0.6（0.2 - 1.6）和0.6（0.2 - 1.8）。这些发现支持了饮食建议，如美国癌症协会、美国国立癌症研究所和美国膳食指南的建议，这些建议允许充足摄入叶酸和维生素C，这两种营养素在水果和蔬菜中含量丰富。增加豆类和全谷物的摄入量也符合当前的饮食建议，这两类食物都是叶酸的良好来源。
