適量應(yīng)用維生素D可減少患結(jié)直腸癌的風(fēng)險(xiǎn),，這是上海交通大學(xué)附屬第六人民醫(yī)院外科馬延磊博士在導(dǎo)師秦環(huán)龍教授的指導(dǎo)下開(kāi)展專(zhuān)項(xiàng)研究所得出的結(jié)論。多年來(lái),，他們課題組經(jīng)過(guò)前瞻性研究的系統(tǒng)綜述,，發(fā)現(xiàn)了維生素D 與結(jié)直腸癌風(fēng)險(xiǎn)間的聯(lián)系,，該項(xiàng)最新研究成果在最近一期的《臨床腫瘤學(xué)期刊》（JCO）上正式發(fā)表，引起國(guó)際同行的注目,。JCO雜志是美國(guó)臨床腫瘤學(xué)會(huì)（ASCO）的官方刊物,，在國(guó)際腫瘤學(xué)界享有盛譽(yù)，2010年影響因子為18.790,。
大腸癌是全球發(fā)病率和致死率較高的惡性腫瘤之一,，在我國(guó)，近年來(lái)隨著人民生活水平的不斷提高,，飲食習(xí)慣和飲食結(jié)構(gòu)的改變以及人口老齡化,，中國(guó)結(jié)直腸癌的發(fā)病率和死亡率均保持上升趨勢(shì)，因此,，大腸癌的預(yù)防尤為關(guān)鍵,。研究者通過(guò)系統(tǒng)綜述的18個(gè)前瞻性臨床研究，共包含了1, 000, 000例參與者,。研究者分別分析了維生素D的攝入水平,、維生素D的血液轉(zhuǎn)化物25-hydroxy 維生素D [25(OH)D] 血液表達(dá)水平與大腸癌發(fā)病風(fēng)險(xiǎn)的相互關(guān)系。結(jié)果發(fā)現(xiàn)：維生素D攝取量較多或者血液中活性維生素D-[25(OH)D] 表達(dá)水平較高的人群,，患大腸癌的概率比較低。維生素D攝取量較低的人群較維生素D攝取量較高的人群,，大腸癌的發(fā)病率增加了67% [0.67 (95% CI,， 0.54-0.80)]。血液中25(OH)D表達(dá)水平較低的人群較血液中25(OH)D表達(dá)較高的人群,，患大腸癌的風(fēng)險(xiǎn)增加了33% [0.88 (95% CI,， 0.80-0.96)]。同時(shí),，據(jù)Dose-Response線性分析發(fā)現(xiàn)：血清中25(OH)D表達(dá)水平每增加10ng/mL,，大腸癌的相對(duì)發(fā)病風(fēng)險(xiǎn)將降低74% [0.74 (95% CI， 0.63-0.89)],。
近十年的流行病學(xué)調(diào)查研究表明,，絕大多數(shù)成年人和許多兒童攝入維生素D的水平及循環(huán)血液中維生素D轉(zhuǎn)化物25(OH)D表達(dá)水平存在嚴(yán)重不足。因此,，通過(guò)此項(xiàng)研究分析,，對(duì)于維生素D在預(yù)防大腸癌的發(fā)病風(fēng)險(xiǎn)中的重要作用將提供充足的證據(jù),。目前，上海交通大學(xué)附屬六院的研究者正在利用從美國(guó)Jackson Laboratory公司引進(jìn)的APCmin突變的自發(fā)性腸道成瘤小鼠,，進(jìn)一步分析維生素D在腸道腫瘤發(fā)生發(fā)展中的分子機(jī)制,，初步的研究結(jié)果已經(jīng)表明：維生素D可以使腸道腫瘤的數(shù)量減少和體積減小，潛在的分子機(jī)制可能由于維生素D缺乏時(shí)DNA合成受抑制,，致使腸上皮細(xì)胞一種保護(hù)性蛋白β-兒茶素在細(xì)胞中的構(gòu)建被破壞,，但具體的分子機(jī)制尚在研究階段。（生物谷 Bioon.com）
doi:10.1200/JCO.2011.35.7566
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Association Between Vitamin D and Risk of Colorectal Cancer: A Systematic Review of Prospective Studies
Yanlei Ma, Peng Zhang, Feng Wang, Jianjun Yang, Zhihua Liu and Huanlong Qin⇓
Purpose To conduct a systematic review of prospective studies assessing the association of vitamin D intake or blood levels of 25-hydroxyvitamin D [25(OH)D] with the risk of colorectal cancer using meta-analysis. Methods Relevant studies were identified by a search of MEDLINE and EMBASE databases before October 2010 with no restrictions. We included prospective studies that reported relative risk (RR) estimates with 95% CIs for the association between vitamin D intake or blood 25(OH)D levels and the risk of colorectal, colon, or rectal cancer. Approximately 1,000,000 participants from several countries were included in this analysis. Results Nine studies on vitamin D intake and nine studies on blood 25(OH)D levels were included in the meta-analysis. The pooled RRs of colorectal cancer for the highest versus lowest categories of vitamin D intake and blood 25(OH)D levels were 0.88 (95% CI, 0.80 to 0.96) and 0.67 (95% CI, 0.54 to 0.80), respectively. There was no heterogeneity among studies of vitamin D intake (P = .19) or among studies of blood 25(OH)D levels (P = .96). A 10 ng/mL increment in blood 25(OH)D level conferred an RR of 0.74 (95% CI, 0.63 to 0.89). Conclusion Vitamin D intake and blood 25(OH)D levels were inversely associated with the risk of colorectal cancer in this meta-analysis.
