Mahabir Somdat, Schendel Kalli, Dong Yong Quan, Barrera Stephanie L, Spitz Margaret R, Forman Michele R
Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Int J Cancer. 2008 Sep 1;123(5):1173-80. doi: 10.1002/ijc.23649.
Studies of vitamin E and cancer have focused on the alpha-tocopherol form of the vitamin. However, other forms of vitamin E, in particular gamma-tocopherol may have unique mechanistic characteristics relevant to lung cancer prevention. In an ongoing study of 1,088 incident lung cancer cases and 1,414 healthy matched controls, we studied the associations between 4 tocopherols (alpha-, beta-, gamma-, and delta-tocopherol) in the diet and lung cancer risk. Using multiple logistic regression analysis, the adjusted odds ratios (OR) and 95% confidence intervals (CI) of lung cancer for increasing quartiles of dietary alpha-tocopherol intake were 1.0, 0.63 (0.50-0.79), 0.58 (0.44-0.76) and 0.39 (0.28-0.53), respectively (p-trend < 0.0001). For dietary intake of beta-tocopherol, the OR and 95% CI for all subjects were: 1.0, 0.79 (0.63-0.98), 0.59 (0.45-0.78) and 0.56 (0.42-0.74), respectively (p-trend < 0.0001). Similar results for dietary gamma-tocopherol intake were observed: 1.0, 0.84 (0.67-1.06), 0.76 (0.59-0.97) and 0.56 (0.42-0.75), respectively (p- trend = 0.0002). No significant association between delta-tocopherol intake and lung cancer risk was detected. When the 4 tocopherols were summed as total tocopherol intake, a monotonic risk reduction was also observed. When we entered the other tocopherols in our model, only the association with dietary alpha-tocopherol intake remained significant; i.e., increasing intake of dietary alpha-tocopherol accounted for 34-53% reductions in lung cancer risk. To the best of our knowledge, this is the first report of the independent associations of the 4 forms of dietary tocopherol (alpha-, beta-, gamma- and delta-tocohperol) on lung cancer risk. Given the limitations with case-control studies, these findings need to be confirmed in further investigations.
关于维生素E与癌症的研究主要集中在维生素的α-生育酚形式上。然而，维生素E的其他形式，特别是γ-生育酚，可能具有与肺癌预防相关的独特作用机制。在一项正在进行的针对1088例新发肺癌病例和1414名健康匹配对照的研究中，我们研究了饮食中4种生育酚（α-、β-、γ-和δ-生育酚）与肺癌风险之间的关联。采用多因素logistic回归分析，饮食中α-生育酚摄入量增加的四分位数对应的肺癌调整比值比（OR）和95%置信区间（CI）分别为1.0、0.63（0.50 - 0.79）、0.58（0.44 - 0.76）和0.39（0.28 - 0.53）（P趋势<0.0001）。对于饮食中β-生育酚的摄入量，所有受试者的OR和95%CI分别为：1.0、0.79（0.63 - 0.98）、0.59（0.45 - 0.78）和0.56（0.42 - 0.74）（P趋势<0.0001）。饮食中γ-生育酚摄入量也观察到类似结果：分别为1.0、0.84（0.67 - 1.06）、0.76（0.59 - 0.97）和0.56（0.42 - 0.75）（P趋势 = 0.0002）。未检测到δ-生育酚摄入量与肺癌风险之间存在显著关联。当将4种生育酚作为总生育酚摄入量相加时，也观察到风险单调降低。当我们在模型中纳入其他生育酚时，仅饮食中α-生育酚摄入量的关联仍然显著；即饮食中α-生育酚摄入量增加可使肺癌风险降低34% - 53%。据我们所知，这是关于饮食中4种生育酚（α-、β-、γ-和δ-生育酚）与肺癌风险独立关联的首次报告。鉴于病例对照研究的局限性，这些发现需要在进一步研究中得到证实。
