Plasma Isoflavones and the Risk of Lung Cancer in Women: A Nested Case-Control Study in Japan

Cancer Epidemiol Biomarkers Prev. 2011 Mar;20(3):419-27. doi: 10.1158/1055-9965.EPI-10-1025. Epub 2011 Jan 14.


Background: 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.

Methods: 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.

Results: 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.

Conclusion: Plasma genistein concentration was inversely associated with lung cancer risk in Japanese women.

Impact: Our data support the previously observed association between isoflavone intake and lung cancer risk.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Cohort Studies
  • Female
  • Genistein / blood
  • Humans
  • Isoflavones / blood*
  • Japan / epidemiology
  • Lung Neoplasms / blood*
  • Middle Aged
  • Prospective Studies
  • Risk Factors


  • Isoflavones
  • Genistein