Japanese Journal of Clinical Oncology Advance Access published online on April 7, 2009
Japanese Journal of Clinical Oncology, doi:10.1093/jjco/hyp028
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© The Author (2009). Published by Oxford University Press. All rights reserved
Flavonoids Intake and Risk of Lung Cancer: A Meta-analysis
1 National Shanghai Center for New Drug Safety Evaluation and Research, Shanghai Institute of Pharmaceutical Industry, Shanghai
2 Department of Pharmacology, Nanjing Medical University
3 Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu Province, China
For reprints and all correspondence: Na-Ping Tang or Jing Ma, National Shanghai Center for New Drug Safety Evaluation and Research, Shanghai Institute of Pharmaceutical Industry, 199 Guoshoujing Road, Zhangjiang Hi-Tech Park, Pudong, Shanghai 201203, China. E-mail: naping.tang{at}gmail.com (N.-P.T.) or jma{at}ncdser.com (J.M.)
Received November 15, 2008; accepted March 12, 2009
Objective: A number of studies have evaluated the association between flavonoids intake and lung cancer risk. However, results were inconsistent. To clarify the role of flavonoids in lung cancer, we conducted a meta-analysis on this topic.
Methods: Two authors independently searched PubMed and EMBASE for studies regarding the association of flavonoids intake with lung cancer risk. Summary relative risks (RRs) with their corresponding 95% confidence intervals (CIs) were calculated by using random-effects model.
Results: Eight prospective studies and four case–control studies involving 5073 lung cancer cases and 237 981 non-cases were included in this meta-analysis. The combined results indicated a statistically significant association between highest flavonoids intake and reduced risk of developing lung cancer (RR = 0.76, 95% CI = 0.63–0.92). Furthermore, an increase in flavonoids intake of 20 mg/day was associated with a 10% decreased risk of developing lung cancer (RR = 0.90, 95% CI = 0.83–0.97). In stratified analyses, the highest flavonoids intake was significantly associated with decreased lung cancer risk in prospective studies, studies conducted in Finnish population, studies without adjustment for fruits and vegetables or vitamins, males, smokers and studies using dietary history interview for flavonoids intake estimation. Most subclasses of flavonoids were inversely associated with lung cancer except for hesperetin.
Conclusions: Our data indicate that high or an increased intake of flavonoids is associated with reduced risk of lung cancer in some population but not in other population.
Key Words: flavonoids • lung cancer • meta-analysis