Sy Alexander M, Bautista Josef Edrik Keith
Department of Medicine, Metropolitan Hospital Center, New York Medical College, New York, NY, USA,
J Gastrointest Cancer. 2013 Dec;44(4):481-5. doi: 10.1007/s12029-013-9533-3.
Vitamin D has been postulated to play a role in colonic carcinogenesis by modulation of apoptosis and inhibition of angiogenesis. However, data supporting this theory are conflicting, and most studies include only Asians and Caucasians. This retrospective study aims to determine whether there is a correlation between an increased total vitamin D level and a lower incidence of carcinomatous polyps in a multi-race but predominantly Hispanic population in East Harlem, New York City.
A case-control study was conducted involving all patients who underwent colonoscopy at Metropolitan Hospital Center in 2011 and who also had serum total vitamin D levels taken within 1 month before or after the date of colonoscopy. Total vitamin D levels and the presence of carcinomatous polyps were the main variables studied. Colonic polyp-positive (CP+) samples were designated as the case group, while colonic polyp-negative (CP-) samples were assigned to the control group. Logistic regression analysis was used to estimate odds ratio at a 95% confidence interval. Adjusted variables were chosen a priori and included age, sex, race, smoking and alcohol history, body mass index, and folate and aspirin use.
We identified 1,640 patients who underwent colonoscopy from January 1 to December 31, 2011. Of these, 136 also had a vitamin D serum level drawn within 1 month before or after the colonoscopy. Forty-three were CP+ and assigned to the cases group, and 93 were CP- and assigned to the control group. Thirty-five percent of the sample had total serum vitamin D levels of <20 ng/ml, and 65% had total serum vitamin D levels 20-29 ng/ml. Using <20 ng/ml as a cutoff point, the association of vitamin D with CP+ was statistically nonsignificant. In a multivariate model using vitamin D levels of <20 and <30, the association with CP+ appeared stronger, though, here too, the associations were not statistically not significant. A post hoc analysis was done excluding vitamin D levels of 20-29. In this analysis, the association between vitamin D levels and colonic polyps grew stronger with increased cutoff levels with vitamin D level of <20, suggesting a threshold effect.
Vitamin D levels, using two established cutoffs, are not significantly associated with increased odds of membership in the CP+ group. However, our data suggest a possible threshold effect of vitamin D at <30 ng/ml associated with increasing odds of being CP+.
维生素D被认为可通过调节细胞凋亡和抑制血管生成在结肠癌发生过程中发挥作用。然而，支持该理论的数据存在矛盾，并且大多数研究仅纳入了亚洲人和高加索人。这项回顾性研究旨在确定在纽约市东哈莱姆区以西班牙裔为主的多种族人群中，总维生素D水平升高与癌性息肉发病率降低之间是否存在关联。
进行了一项病例对照研究，纳入了2011年在大都会医院中心接受结肠镜检查且在结肠镜检查日期前后1个月内检测了血清总维生素D水平的所有患者。总维生素D水平和癌性息肉的存在是主要研究变量。结肠息肉阳性（CP+）样本被指定为病例组，而结肠息肉阴性（CP-）样本被分配到对照组。采用逻辑回归分析在95%置信区间估计比值比。预先选择调整变量，包括年龄、性别、种族、吸烟和饮酒史、体重指数以及叶酸和阿司匹林的使用情况。
我们确定了2011年1月1日至12月31日期间接受结肠镜检查的1640例患者。其中，136例在结肠镜检查前后1个月内还检测了维生素D血清水平。43例为CP+并被分配到病例组，93例为CP-并被分配到对照组。35%的样本血清总维生素D水平<20 ng/ml，65%的样本血清总维生素D水平为20 - 29 ng/ml。以<20 ng/ml为截断点，维生素D与CP+的关联在统计学上无显著意义。在使用<20和<30的维生素D水平的多变量模型中，与CP+的关联似乎更强，不过在此处，这些关联在统计学上也无显著意义。进行了一项排除20 - 29维生素D水平的事后分析。在此分析中，随着截断水平升高，维生素D水平与结肠息肉之间的关联增强，维生素D水平<20时提示存在阈值效应。
采用两个既定的截断点时，维生素D水平与CP+组成员增加的几率无显著关联。然而，我们的数据提示维生素D在<30 ng/ml时可能存在阈值效应，与CP+几率增加相关。
