Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, 104-0045 Japan.
Cancer Epidemiol Biomarkers Prev. 2011 Mar;20(3):419-27. doi: 10.1158/1055-9965.EPI-10-1025. Epub 2011 Jan 14.
Although several epidemiologic studies have found that isoflavone intake assessed by questionnaire is associated with a decreased risk of lung cancer, no prospective study has investigated this association using blood concentrations of isoflavones.
We conducted a nested case-control study within a population-based prospective cohort study. A total of 24,127 women aged 40 to 69 years who returned the baseline questionnaire and provided blood samples were observed from 1990 through 2006. During a median follow-up period of 13.5 years, 126 newly diagnosed lung cancer cases were identified. For each case, we selected two controls matched for age, area, smoking status, and condition of blood draw. A conditional logistic regression model was used to estimate the odds ratios (ORs) and 95% CIs of lung cancer in relation to plasma concentrations of genistein, daidzein, glycitein, equol, and total isoflavones.
After exclusion of 20 lung cancer cases diagnosed in the first 3 years after blood collection, an inverse association was found between plasma genistein concentration and lung cancer risk. The multivariate-adjusted OR (95% CI) of lung cancer in the highest quintile of plasma genistein concentration as compared with that in the lowest quintile was 0.31 (0.12, 0.86; P for trend=0.085). Other isoflavones and total isoflavones were not associated with a significant decrease in the risk of lung cancer.
Plasma genistein concentration was inversely associated with lung cancer risk in Japanese women.
Our data support the previously observed association between isoflavone intake and lung cancer risk.
尽管几项流行病学研究发现，通过问卷调查评估的异黄酮摄入量与肺癌风险降低有关，但没有前瞻性研究使用异黄酮的血液浓度来研究这种相关性。
我们在一项基于人群的前瞻性队列研究中进行了一项巢式病例对照研究。共有 24127 名年龄在 40 至 69 岁之间的女性参加了研究，她们在 1990 年至 2006 年期间返回了基线问卷并提供了血液样本。在中位随访 13.5 年期间，发现了 126 例新诊断的肺癌病例。对于每个病例，我们选择了两个与年龄、地区、吸烟状况和采血条件相匹配的对照。使用条件逻辑回归模型来估计血浆中染料木黄酮、大豆苷元、大豆苷、黄豆黄素和总异黄酮浓度与肺癌之间的比值比（OR）和 95%置信区间（CI）。
在排除了血液采集后 3 年内诊断的 20 例肺癌病例后，发现血浆染料木黄酮浓度与肺癌风险呈负相关。与最低五分位数相比，血浆染料木黄酮浓度最高五分位数的肺癌多变量调整后 OR（95%CI）为 0.31（0.12，0.86；趋势 P 值=0.085）。其他异黄酮和总异黄酮与肺癌风险的显著降低无关。
在日本女性中，血浆染料木黄酮浓度与肺癌风险呈负相关。
我们的数据支持之前观察到的异黄酮摄入量与肺癌风险之间的关联。
